Gearbox for a gas turbine engine with shape memory alloy damper

Abstract

A epicyclic gearbox configured to transmit rotational motion between a first rotating component and a second rotating component of a gas turbine engine. The gearbox includes a sun gear at a center, two or more planet gears encircling the sun gear, and a ring gear encircling the plurality of planet gears. The gearbox is configured such that the sun gear is drivingly coupled to the first rotating component such that rotation of the sun gear causes rotation of each planet gear, and such that the ring gear rotates relative to the plurality of planet gears. The gearbox includes one or more shape memory alloy dampers disposed in association with the sun gear, the ring gear, and / or the plurality of planet gears. The shape memory alloy dampers are configured to reduce vibrations transmitted through the epicyclic gearbox to the frame, the first rotating component, and / or the second rotating component.

Description

[0001] Priority Information

[0002] This application claims priority to Indian Patent Application No. 202011053386 filed on December 8, 2020. TECHNICAL FIELD

[0003] The present subject matter relates generally to a gear box of a gas turbine engine, or more specifically, to a gear box of a gas turbine engine having a damper that includes a shape memory alloy material to reduce vibrations transmitted through the gear box. BACKGROUND

[0004] Gas turbine engines generally include a turbine and a rotor assembly. In the case of a turbofan engine, the rotor assembly can be configured as a fan assembly. The turbine generally includes a high pressure, high speed spool and a low pressure, low speed spool. A combustion section receives pressurized air, which is mixed with fuel and combusted within a combustion chamber to produce combustion gases. The combustion gases are first provided to a high pressure turbine of the high pressure spool, driving the high pressure spool, and subsequently provided to a low pressure turbine of the low speed spool, driving the low speed spool. The rotor assembly is generally coupled to the low speed spool.

[0005] The low pressure spool can drive a fan through a power gear box, which allows the fan to rotate at fewer revolutions per unit of time than the rotational speed of the low speed spool, thereby improving efficiency. The power gear box generally includes a sun gear, one or more planet gears, and a ring gear. In a typical epicyclic gear arrangement, the gear box rotatably supports the sun gear, which is centrally disposed relative to the ring gear and the plurality of planet gears, which are disposed about the sun gear and engaged between the sun gear and the ring gear. The low speed spool provides input to the epicyclic gear arrangement through a coupling to the sun gear, while the fan can be coupled to rotate with either the planet gear carrier or the ring gear, depending on whether a star gear box or a planetary gear box is used. Each planet gear meshes with the sun gear and the ring gear. One of the carrier or the ring gear can remain stationary, but both cannot remain stationary. Such gear boxes can be subjected to various vibrations transmitted through the gear box between one or more spools of the gas turbine engine, between a spool of the gas turbine and the gear box, or between the gear box and a static structure of the gas turbine engine.

[0006] Accordingly, it would be useful to have a gear box of a gas turbine engine having one or more features for reducing vibrations transmitted through the gear box between rotating components or between rotating components and static structures. SUMMARY

[0007] Aspects and advantages of the application will be set forth in part in the following description, or can be obvious from the description, or can be learned through practice of the application.

[0008] In one aspect, the present subject matter relates to an epicyclic gearbox configured to be supported by a frame of a gas turbine engine and configured to transmit rotational motion between a first rotating component of the gas turbine engine and a second rotating component of the gas turbine engine. The gearbox includes a sun gear located at a center, the sun gear including a plurality of teeth. The sun gear is configured to be drivingly coupled to the first rotating component of the gas turbine engine. The epicyclic gearbox further includes two or more planet gears that surround the sun gear. Each planet gear includes a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each planet gear. In addition, the gearbox includes a ring gear that surrounds the plurality of planet gears. The ring gear includes a plurality of teeth configured to mesh with the teeth of each planet gear such that the ring gear rotates relative to the planet gears. Further, the gearbox includes one or more shape memory alloy dampers disposed in association with the sun gear, the ring gear, and / or the plurality of planet gears. The shape memory alloy dampers are configured to reduce vibrations transmitted through the epicyclic gearbox to the frame, the first rotating component, and / or the second rotating component of the gas turbine engine.

[0009] In another aspect, the present subject matter relates to a gas turbine engine defining a central axis. The gas turbine engine includes a frame, a turbine section including a turbine, and a fan assembly including a fan. The gas turbine engine additionally includes an epicyclic gearbox supported by the frame and drivingly coupling the turbine of the turbine section to the fan of the fan assembly. The epicyclic gearbox includes a sun gear located at a center, the sun gear including a plurality of teeth. The sun gear is drivingly coupled to the turbine of the turbine section. The epicyclic gearbox further includes two or more planet gears that surround the sun gear. Each planet gear includes a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each planet gear. The epicyclic gearbox further includes a ring gear that surrounds the planet gears. The ring gear includes a plurality of teeth configured to mesh with the teeth of each planet gear such that the ring gear rotates relative to the planet gears. In addition, the epicyclic gearbox includes one or more shape memory alloy dampers disposed in association with the sun gear, the ring gear, and / or the planet gears such that vibrations transmitted through the epicyclic gearbox to the frame, the turbine, and / or the fan of the gas turbine engine are reduced.

[0010] These and other features, aspects, and advantages of the present application will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and serve to explain the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0011] A complete and enabling disclosure of the application, directed to one of ordinary skill in the art, is set forth in the specification in conjunction with the attached drawings, of which:

[0012] Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure.

[0013] Figure 2 is a schematic cross-sectional view of a gas turbine engine according to another exemplary embodiment of the present disclosure.

[0014] Figure 3 is another schematic cross-sectional view of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0015] Figure 4 is a schematic view of a sun and planet gear box of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0016] Figure 5 is a schematic cross-sectional view of a sun and planet gear box for a gas turbine engine according to another exemplary aspect of the present disclosure.

[0017] Figure 6 is a bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0018] Figure 7 is an additional or alternative bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0019] Figure 8 is an additional or alternative bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0020] Figure 9 is an additional or alternative bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0021] Figure 10 is an additional or alternative bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0022] Figure 11 is an additional or alternative bearing damper including SMA material suitable for various gear boxes of a gas turbine engine according to another exemplary aspect of the present disclosure.

[0023] Figure 12is a schematic cross-sectional view of an additional or alternative gear box for a gas turbine engine according to another example aspect of the present disclosure.

[0024] Figure 13 is a schematic cross-sectional view of an additional or alternative gear box for a gas turbine engine according to another example aspect of the present disclosure.

[0025] Figure 14 is a schematic cross-sectional view of an additional or alternative gear box for a gas turbine engine according to another example aspect of the present disclosure.

[0026] Figure 15 is a schematic cross-sectional view of an SMA external damper adapted on a planet carrier of a gear box according to another example aspect of the present disclosure.

[0027] Figure 16 is a diagrammatic schematic of a fluid transfer system of a gas turbine engine according to another example aspect of the present disclosure.

[0028] Figure 17 is a schematic cross-sectional view of a dual adapted SMA dampened fluid conduit for a fluid transfer system of a gas turbine engine according to another example aspect of the present disclosure.

[0029] Figure 18 is a schematic cross-sectional view of an additional or alternative dual adapted SMA dampened fluid conduit for a fluid transfer system of a gas turbine engine according to another example aspect of the present disclosure.

[0030] Figure 19 is a diagrammatic schematic of a SMA clamp of a fluid transfer system of a gas turbine engine according to another example aspect of the present disclosure.

[0031] Reference numbers repeated in the specification and drawings are intended to refer to the same or like components or elements throughout the specification and drawings. DETAILED DESCRIPTION

[0032] Reference will now be made in detail to the presently preferred embodiments of the application, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations

[0033] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0034] As used herein, the terms “first,” “second,” and “third” can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0035] The terms “forward” and “aft” refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, forward refers to a position closer to the engine inlet and aft refers to a position closer to the engine nozzle or exhaust.

[0036] The terms “upstream” and “downstream” refer to the relative direction with respect to the flow of fluid in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows and “downstream” refers to the direction to which the fluid flows.

[0037] The terms “coupled,” “fixed,” “attached to” and like terms, unless stated to the contrary, refer to direct and indirect coupling, fixation, or attachment by one or more intermediate parts or features.

[0038] The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0039] Approximating language as used herein is used to convey that a value can vary from the stated value by an acceptable amount, such as within 1%, 2%, 4%, 10%, 15%, or 20%. As used herein, the term “about” is used to indicate that a value is within a reasonable expected range of the stated value, and thus such a term can be construed to cover a range of values that are close to the stated value. For example, a range of values that is within 10% of a stated value can be covered by the term “about.” As used herein, the term “substantially” is used to indicate that a value is within a range that is close to the stated value, such as within 10% of the stated value.

[0040] Ratios, concentrations, amounts, and other numerical data can be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted in the context of the specifi c application. Therefore, numerical upper and lower limits set forth in these ranges can independently be combined. Specifically, ranges can include the minimum and maximum values of the ranges, and also include any value or sub-range between the minimum and maximum values of the ranges. For example, a range of 1 to 10 can include any value or sub-range between 1 and 10, e.g., 7.1 to 8.3, or 5.75 to 9.98.

[0041] In some embodiments, one or more components of the gas turbine engine described below can be manufactured or formed using any suitable process (e.g., an additive manufacturing process, such as a 3-D printing process). The use of such processes can allow such components to be integrally formed as a single monolithic component, or as any suitable number of sub-components. In particular, additive manufacturing processes can allow such components to be integrally formed and include a variety of features that would not be possible using existing manufacturing methods. For example, the additive manufacturing methods described herein can enable the manufacture of a gear case, components of a gear case, shape memory alloy dampers suitable for use in such gear cases, and / or shape memory alloy dampers suitable for use in a gas turbine engine or within a fluid conduit system of a gas turbine engine. Such components can have unique features, configurations, thicknesses, materials, densities, fluid passages, manifolds, and mounting structures that can not be possible or practical using existing manufacturing methods. Some of these features are described herein.

[0042] As used herein, the term "additive manufacturing" or "additive manufacturing techniques or processes" generally refers to manufacturing processes in which successive layers of material are provided to one another to "build up" a three-dimensional component layer-by-layer. The successive layers are typically fused together to form a monolithic component that can have a variety of integral sub-components. Although additive manufacturing techniques are described herein as being capable of manufacturing complex objects by building up objects point-by-point, layer-by-layer in a generally vertical direction, other manufacturing methods are possible and within the scope of the present subject matter. For example, although the discussion herein relates to the addition of material to form successive layers, those skilled in the art will appreciate that the methods and structures disclosed herein can be practiced with any additive manufacturing technique or manufacturing technique. For example, embodiments of the present application can use a layer-additive process, a layer-removal process, or a hybrid process.

[0043] Referring now to the drawings, Figure 1 A front cross-sectional view of an exemplary embodiment of a gas turbine engine that can incorporate one or more inventive aspects of the present disclosure is shown. In particular, Figure 1 The exemplary gas turbine engine of FIG. 1 is configured as a single spool ducted engine 10 that defines an axial direction A, a radial direction R, and a circumferential direction C (extending around the axial direction A). From Figure 1As can be seen, the engine 10 takes the form of a closed rotor propulsion system and has a rotor assembly 12 (e.g., a fan assembly) that includes an array of airfoils arranged about a central longitudinal axis 14 of the engine 10, and more particularly, an array of rotor blades 16 arranged about the central longitudinal axis 14 of the engine 10. Moreover, as will be explained in greater detail below, the engine 10 additionally includes a non-rotating vane assembly 18 positioned aft of the rotor assembly 12 (i.e., not rotating relative to the central axis 14), the non-rotating vane assembly 18 including an array of airfoils also arranged about the central axis 14, and more particularly, an array of vanes 20 (e.g., outlet guide vanes) arranged about the central axis 14.

[0044] The rotor blades 16 are arranged in generally equally spaced relation about the centerline 14, and each blade has a root 22 and a tip 24 with a span defined therebetween. Similarly, the vanes 20 are also arranged in generally equally spaced relation about the centerline 14, and each vane has a root 26 and a tip 28 with a span defined therebetween. The rotor assembly 12 also includes a hub 43 forward of the plurality of rotor blades 16.

[0045] Additionally, the engine 10 includes a turbomachine 30 having a core (or high speed system) 32 and a low speed system. The core 32 generally includes a high speed compressor 34, a high speed turbine 36, and a high speed shaft 38 extending therebetween and connecting the high speed compressor 34 and the high speed turbine 36. The high speed compressor 34 (or at least the rotating components thereof), the high speed turbine 36 (or at least the rotating components thereof), and the high speed shaft 38 can be collectively referred to as a high speed spool 35 of the engine. Moreover, a combustion section 40 is located between the high speed compressor 34 and the high speed turbine 36. The combustion section 40 can include one or more configurations for receiving a mixture of fuel and air and providing a flow of combustion gases through the high speed turbine 36 to drive the high speed spool 35.

[0046] The low speed system similarly includes a low speed turbine 42, a low speed compressor or booster 44, and a low speed shaft 46 extending between and connecting the low speed compressor 44 and the low speed turbine 42. The low speed compressor 44 (or at least the rotating components thereof), the low speed turbine 42 (or at least the rotating components thereof), and the low speed shaft 46 can be collectively referred to as a low speed spool 45 of the engine.

[0047] Although the engine 10 is depicted with the low speed compressor 44 positioned forward of the high speed compressor 34, in certain embodiments, the compressors 34, 44 can be in a cross- arrangement. Additionally or alternatively, although the engine 10 is depicted with the high speed turbine 36 positioned forward of the low speed turbine 42, in certain embodiments, the turbines 36, 42 can similarly be in a cross- arrangement.

[0048] Still referringFigure 1 Turbomachinery 30 is generally enclosed in shroud 48. Further, it should be appreciated that shroud 48 at least partially defines inlet 50 and exhaust 52, and includes turbomachinery flowpath 54 extending between inlet 50 and exhaust 52. For the illustrated embodiment, inlet 50 is an annular or axisymmetric 360-degree inlet 50 located between rotor blade assembly 12 and stationary or stator vane assembly 18, and provides a path for incoming atmospheric air in a radial direction R into turbomachinery flowpath 54 (and compressor 44, 34, combustion section 40, and turbines 36, 42) on the inside of guide vanes 20. Such a location can be advantageous for a variety of reasons, including management of icing performance and protection of inlet 50 from various objects and materials that can be encountered in operation. However, in other embodiments, inlet 50 can be positioned in any other suitable location (e.g., aft of vane assembly 18), arranged in a non-axisymmetric manner, etc.

[0049] As noted above, engine 10 includes vane assembly 18. Vane assembly 18 extends from shroud 48 and is positioned aft of rotor assembly 12. Vanes 20 of vane assembly 18 can be mounted to a stationary frame or other mounting structure, and do not rotate relative to central axis 14. For reference purposes, Figure 1 The forward direction is also depicted with arrow F, which in turn defines a forward portion and an aft portion of the system. As Figure 1 shown, rotor assembly 12 is positioned forward of turbomachinery 30 in a “puller” configuration, and exhaust 52 is positioned aft of guide vanes 20. It should be appreciated that vanes 20 of vane assembly 18 can be configured to straighten the airflow from rotor assembly 12 (e.g., reduce the amount of swirl in the airflow), to improve the efficiency of engine 10. For example, the size, shape, and configuration of vanes 20 can be set to impart a counter-swirl to the airflow from rotor blades 16, such that the degree of swirl in the airflow is greatly reduced in a downstream direction aft of both rows of airfoils (e.g., blades 16, vanes 20), which can translate into an increased level of induced efficiency.

[0050] Still referring to Figure 1 It can be desirable for rotor blades 16, vanes 20, or both, to incorporate a pitch mechanism, such that the airfoils (e.g., blades 16, vanes 20, etc.) can be rotated independently or in conjunction with one another relative to a pitch rotation axis. Such pitch can be used to vary the thrust and / or swirl effects under various operating conditions, including adjusting the magnitude or direction of thrust generated at rotor blades 16, or to provide a thrust reversal feature (which can be useful in certain operating conditions, such as when the aircraft is landing), or to ideally adjust the noise generated at least partially by rotor blades 16, vanes 20, or the aerodynamic interaction from rotor blades 16 relative to vanes 20. More specifically, for Figure 1In the embodiment depicted, rotor assembly 12 is depicted as having pitch mechanisms 58 for rotating rotor blades 16 about their respective pitch axes 60, and vane assembly 18 is depicted as having pitch mechanisms 62 for rotating vanes 20 about their respective pitch axes 64.

[0051] As shown, rotor assembly 12 is driven by turbine 30, and more particularly, by low speed spool 45. More particularly, Figure 1 Engine 10 in the illustrated embodiment includes a power gear box 56, and rotor assembly 12 is driven by low speed spool 45 of turbine 30 across power gear box 56. Power gear box 56 can include a gear set for reducing the rotational speed of low speed spool 45 relative to low speed turbine 42, such that rotor assembly 12 can rotate at a slower rotational speed than low speed spool 45. In this manner, rotating rotor blades 16 of rotor assembly 12 can rotate about axis 14 and generate thrust to propel engine 10, and thus an aircraft associated therewith, in forward direction F. As Figure 1 Further shown, exemplary engine 10 includes a nacelle 80 at least partially circumferentially surrounding rotor assembly 12 and turbine 30, defining a bypass passage 82 therebetween.

[0052] Still referring to Figure 1 Exemplary engine 10 includes an accessory gear box 66 and an electric machine 68, with turbine 30 driving accessory gear box 66 and electric machine 68. For example, in certain exemplary embodiments, accessory gear box 66 can be coupled to low speed spool 45 (e.g., low speed shaft 46) by a suitable gear train, and electric machine 68 can be coupled to accessory gear box 66. However, in other exemplary embodiments, electric machine 68 can be coupled to low speed spool 45 of turbine 30 independently of accessory gear box 66, and accessory gear box 66 can be coupled to low speed spool 45 or high speed spool 35.

[0053] However, it should be understood that Figure 1 The exemplary single-rotor ducted engine depicted in FIG. 1 is by way of example only, and in other exemplary embodiments, engine 10 can have any other suitable configuration, including for example any other suitable number of shafts or spools, turbines, compressors, etc. Additionally or alternatively, in other exemplary embodiments, any other suitable gas turbine engine can be provided. For example, in other exemplary embodiments, the gas turbine engine can be a non-ducted engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.

[0054] For example, referring now to Figure 2 A front cross-sectional view of another exemplary embodiment of a gas turbine engine that can incorporate one or more inventive aspects of the present disclosure is disclosed. In particular,Figure 2 An exemplary gas turbine engine of the present disclosure is configured as a single rotor, un-ducted engine 10. Figure 2 Exemplary embodiments of the present disclosure can be configured in substantially the same manner as the exemplary engine 10 described above with respect to Figure 1 Exemplary embodiments of the present disclosure can be configured in substantially the same manner as the exemplary engine 10 described above with respect to Figure 2 In the embodiment shown, the engine 10 includes a rotor assembly 12 including an array of airfoils arranged about a central longitudinal axis 14 of the engine 10, and more particularly, an array of rotor blades 16 arranged about the central longitudinal axis 14 of the engine 10. The exemplary engine 10 also includes a non-rotating vane assembly 18 positioned aft of the rotor assembly 12 (i.e., not rotating relative to the central axis 14), the non-rotating vane assembly 18 including an array of airfoils also arranged about the central axis 14, and more particularly, an array of vanes 20 arranged about the central axis 14.

[0055] However, it will be appreciated that for the open rotor propulsion system embodiment shown, the engine 10 includes an un-ducted or open array of rotor blades 16 and an array of vanes. In additional or alternative embodiments, it will be appreciated that at least one of the array of rotor blades 16 or the array of vanes 20 can be ducted, while at least one of the array of vanes 20 or the array of rotor blades 16 is in an open arrangement. Figure 2

[0056] Referring now to Figure 3 , a schematic view of a gas turbine engine 10 according to exemplary embodiments of the present disclosure is depicted. Figure 3 An exemplary gas turbine engine 10 of the present disclosure can be configured in a similar manner as the exemplary engine 10 described above with respect to Figure 1 or Figure 2 Exemplary embodiments of the present disclosure can be configured in substantially the same manner as the exemplary engine 10 described above with respect to

[0057] ​In this manner, the accessory gearbox 66 can transfer rotational power from the low speed spool 45 of the engine 10 to, for example, one or more accessory systems 70 of the engine 10 or an aircraft incorporating the engine 10, which are mechanically coupled to the accessory gearbox 66 and the electric machine 68 (which can rotate with the accessory gearbox 66). The engine 10 also includes a rotor assembly 12 and a power gearbox 56, where the rotor assembly 12 is driven across the power gearbox 56 by the low speed spool 45. More specifically, for the illustrated embodiment, the power gearbox 56 defines a gear ratio for reducing the rotational speed of the rotor assembly 12 relative to the low pressure spool 45. In at least certain example embodiments, the gear ratio can be greater than or equal to about 4: 1 and less than or equal to about 12: 1. For example, in certain example embodiments, the gear ratio can be between greater than or equal to about 7: 1 and less than or equal to about 12: 1. In this case, the power gearbox 56 can be a multi-stage or compound power gearbox (e.g., a planetary gearbox with a compound planetary gear, etc.).

[0058] It should be appreciated that various electrical and other accessory systems of the gas turbine engine 10 are typically powered by the core 32 of the engine 10, or more specifically, by an accessory gearbox driven by the high speed / high pressure system of the engine 10. With such a configuration, the engine core 32 is typically oversized to allow these accessory systems to operate throughout the flight envelope. However, it is worth noting that this configuration can reduce the responsiveness of the engine 10 by virtue of the additional load and inertia on the core 32 of the engine 10. It should be appreciated that by coupling the accessory gearbox 66 and the electric machine 68 to the low speed spool 45 of the engine 10 opposite the high speed spool 35, the gas turbine engine 10 can have a core 32 that is more responsive. Moreover, while this can again result in a less responsive low speed system and rotor assembly 12, the inclusion of the electric machine 68 can make up for the responsiveness.

[0059] Still referring to Figure 3 , it should be appreciated that the electric machine 68 is coupled to the low speed spool 45 of the turbine 30 at a connection point 100. More specifically, for the illustrated embodiment, the accessory gearbox 66 is coupled to the low speed spool 45 at the connection point 100 and the electric machine 68 is coupled to the low speed spool 45 through the accessory gearbox 66. Moreover, for the illustrated embodiment, the turbine 30 includes a gear train 102 coupled to the low speed spool 45 at the connection point 100 and extending to the accessory gearbox 66. In this manner, the accessory gearbox 66 can transfer rotational power from the low speed spool 45 of the engine 10 to, for example, one or more accessory systems 70, which are mechanically coupled to the accessory gearbox 66 and the electric machine 68 (which can rotate with the accessory gearbox 66).

[0060] Moreover, as Figure 3As shown, the example gas turbine engine 10 includes an engine clutch 104 positioned in the torque path of the low speed spool 45 at a location forward of the connection point 100 (where the accessory gear box 66 is coupled to the low speed spool 45 by the gear train 102). Specifically, for the illustrated embodiment, the engine clutch 104 is positioned in the torque path of the low speed spool 45 between the connection point 100 and the rotor assembly 12.

[0061] The engine clutch 104 can be movable between an engaged position, in which torque can be transferred across the engine clutch 104 along the low speed spool 45 to drive the rotor assembly 12 (or vice versa), and a disengaged position, in which torque can not be transferred across the engine clutch 104 along the low speed spool 45 to the rotor assembly 12. In this manner, the engine clutch 104 can facilitate operation of the engine 10 without rotating the rotor assembly 12. This can be beneficial, particularly during certain ground operations, in which it can be desirable to rotate the turbine 30 without generating thrust from the rotor assembly 12.

[0062] In at least certain example aspects, the engine clutch 104 can be a two-stage clutch for transitioning from the disengaged position to the engaged position. It will be appreciated that when the engine clutch 104 is in the disengaged position, the low speed spool 45 can be free to rotate relative to the rotor assembly 12. By contrast, when the engine clutch 104 is in the engaged position, the low speed spool 45 rotates with the rotor assembly 12. It will be further appreciated that this configuration can allow for improved operation of the gas turbine engine 10. For example, this configuration can allow the core 32 of the gas turbine engine 10 to operate during, for example, idle and post-landing operations, without participating in rotating the rotor assembly 12. In this manner, the size of the electric machine 68 can be designed to accept 100% of the rated engine power, such that the gas turbine engine 10 can operate at rated engine power without engaging the rotor assembly 12 (i.e., by moving the engine clutch 104 to the engaged position), and have the electric machine 68 convert substantially all of this power to electrical energy for provision to an aircraft incorporating the gas turbine engine 10 through the electrical bus 120, to one or more energy storage units within or in electrical communication with the bus 120, to assist in starting additional engines, combinations thereof, and the like. Subsequently, when it is desirable to generate thrust with the rotor assembly 12, the engine clutch 104 can be moved from the disengaged position to the transition position, slowly bring the rotor assembly 12 up to speed, and then move the engine clutch 104 to the engaged position, rotationally locking the rotor assembly 12 to the low speed spool 45.

[0063] It should also be understood that, with the above-described configuration, once the engine clutch 104 is engaged, the motor 68 can be used to accelerate the rotor assembly 12 more rapidly during pre-flight operations. More specifically, electricity can be supplied to the motor 68 and converted into rotational power supplied to the low-speed spool 45 via the accessory gearbox 66 to directly aid in accelerating the rotor assembly 12. Although the accessory gearbox 66 is mounted to the low-speed spool 45, this ensures that the low-speed spool 45 has the desired responsiveness.

[0064] It should also be understood that, in this way, motor 68 can be used to start or assist in starting engine 10. (Still referencing...) Figure 3 As illustrated in the embodiment, it should be understood that the depicted exemplary engine 10 also includes an inter-spool clutch 122 positioned between the low-speed / low-pressure system and the high-speed / high-pressure system of the gas turbine engine 10. Specifically, in the illustrated embodiment, the inter-spool clutch 122 is positioned between the low-speed spool 45 and the high-speed spool 35. The inter-spool clutch 122 ensures that the low-speed / low-pressure system does not rotate faster than the high-speed / high-pressure system. The inter-spool clutch 122 can be, for example, a one-way clutch, such as a wedge clutch. In this way, the motor 68 can be used as a starter motor for the gas turbine engine 10. For example, during startup operation, the motor 68 can receive power via the power bus 120 and convert this power into mechanical power transmitted to the low-speed spool 45 via the accessory gearbox 66 and gear train 102, thereby rotating the low-speed spool 45. This rotation engages the inter-spool clutch 122, causing the low-speed spool 45 to rotate the high-speed spool 35 accordingly across the inter-spool clutch 122. Once the gas turbine engine 10 has reached its ignition point, allowing the combustion zone to be ignited and begin producing combustion gases to drive the high-speed system, the high-speed spool 35 can rotate faster than the low-speed spool 45, and the spool clutch 122 can automatically disengage, thus allowing this speed difference. In this way, although connected to the low-speed spool 45, the motor 68 can assist in starting the engine 10 by directly rotating the high-speed spool 35.

[0065] Still referencing Figure 3 In one embodiment, once the aircraft including the gas turbine engine 10 has landed, the engine clutch 104 can disengage (i.e., move to the disengaged position), allowing the rotor assembly 12 to shut down immediately after thrust from the engine 10 is no longer needed. This allows for additional cooling time for the gas turbine engine 10, allows the gas turbine engine 10 to provide full electric power on the ground without operating the rotor assembly 12 (and without generating significant thrust), enabling electric ground taxiing, etc.

[0066] It should be appreciated, however, that in other example embodiments, the engine 10 can have any other suitable configuration. For example, the electric machine 68 can be coupled to the low speed spool 45 at an electric machine connection point independent of the accessory gear case 66, and the accessory gear case 66 can be coupled to the low speed spool 45 at a different low speed spool connection point. For example, the electric machine 68 can be coupled through an electric machine gear train, and the accessory gear case 66 can be coupled through a separate accessory gear case gear train. Still in further embodiments, such an electric machine 68 and / or accessory gear case 66 can not be included. Other configurations are also contemplated.

[0067] Reference will now be made to Figure 4 , a close-up schematic view of a epicyclic gear case assembly (gear case 150) in accordance with example embodiments of the present disclosure is provided. The example gear case 150 more particularly includes an epicyclic gear set 152. However, in other embodiments, the gear case 150 can have any other suitable configuration. Figure 4 Embodiments of the Figure 1 and 2 described above with reference to the power gear case 56. The gear case 150 can be incorporated into the single uncanalized rotor engine 10 described above with reference to Figure 1 and Figure 2 , or alternatively can be incorporated into any other suitable gas turbine engine (e.g., a turboprop engine, a turbofan engine, another suitable uncanalized engine, another suitable canalized engine, etc.). As described above, the rotor assembly 12 of the engine 10 includes rotor blades 16 that are rotatable with the rotor assembly 12. Further, the low speed spool 45 includes a low speed shaft 46 that is rotatable with the low speed turbine 42. Further, the power gear case 56 is mechanically coupled to the rotor assembly 12 and the low speed shaft 46 such that the rotor assembly 12 is rotatable across the power gear case 56 by the low speed shaft 46. However, it should be appreciated that the following description is equally applicable to any other gear case of a suitable gas turbine engine, such as the accessory gear case 66 of the engine 10 described above with reference to Figure 1-3 .

[0068] For this embodiment, the epicyclic gear set 152 includes a ring gear 154, two or more planetary gears 156, and a sun gear 158. The gear case 150 defines a central axis 153, a radial direction R with respect to the central axis 153, and a circumferential direction C extending around the central axis 153. For the illustrated embodiment, the central axis 153 can extend along the central longitudinal axis 14 of the engine 10 such that the radial direction R and the circumferential direction C are aligned with the longitudinal direction L and the lateral direction T of the engine 10, respectively. However, it should be appreciated that the central axis 153 can extend along any other suitable axis of the engine 10, and that the radial direction R and the circumferential direction C can be aligned with any other suitable directions of the engine 10. Figure 1-3The radial direction R and the circumferential direction C are the same for the exemplary engine 10 shown. However, in other embodiments, the central axis 153 can be displaced from the central longitudinal axis 14, e.g., in the accessory gear case 66, such that the gear case 150 defines its own local radial and circumferential directions.

[0069] For the depicted embodiment, the sun gear 158 can be attached to and rotatable with the low speed shaft 46 such that the sun gear 158 can rotate about the central axis 153 of the gear case 150 by the low pressure turbine 42. Further, for the depicted embodiment, the ring gear 154 is fixedly connected to the rotor assembly 12 such that the ring gear 154 rotates with the rotor assembly 12. Figure 4

[0070] Further, for the depicted embodiment, the epicyclic gear set 152 includes a plurality of planet gears 156 engaged between the sun gear 158 and the ring gear 154. Specifically, for the depicted embodiment, the epicyclic gear set 152 includes four planet gears 156 engaged between the sun gear 158 and the ring gear 154. However, in other embodiments, the epicyclic gear set 152 can include any other suitable number of planet gears 156, e.g., three planet gears 156, five planet gears 156, six planet gears 156, etc. Each of the plurality of planet gears 156 can rotate about a respective planet gear axis 160 and can be rotatably attached to a planet carrier 161. For example, in the depicted embodiment, each planet gear 156 can define a central bore 164 configured to receive a corresponding counter shaft 166 of the planet carrier 161. The planet carrier 161 can include a plurality of counter shafts 166 extending in the axial direction A of the gear case 150 and received within the central bores 164 of the corresponding number of planet gears 156 such that each planet gear 156 can rotate about its respective planet gear axis 160.

[0071] Further, for the depicted embodiment, the planet carrier 161 is a fixed planet carrier 161 connected to a ground structure 162 of the engine 10. For example, the planet carrier 161 can be attached to a gear case assembly housing, a stationary frame of the engine 10, the shroud 48, or other suitable mounting structure of the engine 10. Further, each of the exemplary planet gears 156 is a single gear (i.e., the epicyclic gear set 152 is configured as a single stage gear case). However, it should be appreciated that in other embodiments, one or more of the planet gears 156 can instead be configured as a compound gear defining any suitable gear ratio. For example, a compound gear can include two or more gear portions that rotate together on a common gear shaft and mesh with respective mating gears at different axial positions (such that, e.g., the epicyclic gear set 152 defines multiple “stages” as compared to the depicted single stage arrangement).

[0072] ​During operation of the gear case 150 configured as the power gear case 56, the plurality of teeth 159 of the sun gear 158 mesh with the plurality of teeth 157 of the planet gears 156 such that rotation of the sun gear 158 and the low pressure shaft 46 in turn causes each of the plurality of planet gears 156 to rotate about their respective planet gear axes 160. The plurality of teeth 157 of the planet gears 156 also mesh with the plurality of teeth 155 of the ring gear 154 such that rotation of the planet gears 156 about their respective planet gear axes 160 in turn causes the ring gear 154 and the rotor assembly 12 to rotate about the engine axis 14.

[0073] It should be appreciated that the planet gears 156 and the carrier 161 remain stationary in the circumferential direction C of the epicyclic gear set 152 Figure 4 The exemplary gear case configuration of the gear case 150 can be referred to as a star gear case. More specifically, Figure 4 The gear case 150 is configured as a reverse rotation star gear case such that the sun gear 158 and the ring gear 154 rotate in opposite directions relative to the circumferential direction C. However, in other embodiments, one of the ring gear 154 or the sun gear 158 can alternatively remain stationary such that the gear case 150 is alternatively configured as or referred to as a planetary gear case or a differential gear case, respectively. Moreover, in one or more embodiments, the gear case 150 can be configured such that the low pressure shaft 46 and the rotor assembly 12 rotate coaxially or in the same circumferential direction C relative to the longitudinal axis 14 of the engine 10.

[0074] Reference is now made to Figure 5 A schematic cross-sectional view of a gear case of a gas turbine engine in accordance with exemplary embodiments of the present disclosure is provided. The exemplary reverse rotation star gear case 150 can be incorporated in the exemplary engine 10 discussed above with reference to Figure 1-3 or alternatively, in any other suitable gas turbine engine (e.g., a non- ducted rotor engine of a different configuration, a ducted rotor engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.), any other suitable internal combustion engine utilizing a gear case, etc. The gear case 150 will be generally described with respect to the power gear case 56, but the following disclosure can equally apply to any other gear case utilizing any other suitable epicyclic gear case configuration, such as a planetary gear case configuration or a differential gear case configuration, e.g., an accessory gear case.

[0075] Therefore, gearbox 150 may generally include a first attachment structure 168, which is coupled to the sun gear 158 and configured to be coupled to a first rotating component of engine 10. For example, when gearbox 150 is configured as power gearbox 56, the first rotating component may be the low-pressure shaft 46 of the low-pressure shaft 45. Thus, the first attachment structure 168 may be coupled between the sun gear 158 and at least one turbine 36, 42 of engine 10. However, in other embodiments, the sun gear 158 may be directly coupled to a rotating shaft of engine 10, such as the low-pressure shaft 46 or the high-pressure shaft 38. Furthermore, gearbox 150 may generally include a second attachment structure 170, which is coupled to the ring gear 154 and configured to be coupled to a second rotating component of engine 10. For example, when gearbox 150 is configured as power gearbox 56, the second rotating component may be rotor assembly 12. Thus, the second attachment structure 170 may be coupled between the ring gear 154 and the rotating blades 16 of engine 10. However, in other embodiments, the ring gear 154 may be directly coupled to the rotor assembly 12. Alternatively, when incorporated into another engine or other gearbox, the ring gear 154 and / or the sun gear 158 may be configured to be coupled to any other rotating shaft or component of the engine.

[0076] like Figure 5 As shown, the planet carrier 161 can be accessed via the secondary shaft 166 of the planet carrier 161 (in... Figure 5 In the embodiments shown, only one of each of the planetary gears 156 and countershafts 166 is connected to or supports a plurality of planetary gears 156. As shown, the planet carrier 161 can be connected to the grounding structure 162 of the engine 10. For example, the planet carrier 161 can be directly connected to the frame of the engine 10, the cover 48 of the engine 10, the gearbox assembly housing, or other suitable mounting structures of the engine 10. Thus, the planet carrier 161 can be directly or indirectly connected to the frame of the engine 10 such that the planet carrier 161 supports the gearbox 150 relative to the engine 10. However, in other embodiments, the planet carrier 161 can be connected to the attachment structure 170 or directly to the rotor assembly 12 such that the planet carrier 161 rotates together with the rotor assembly 12 about the central axis 153 of the gearbox 150, while the sun gear 158 is connected to the engine frame (planetary gearbox configuration).

[0077] like Figure 5As shown, the gear case can also include one or more bearing assemblies 171, each corresponding to each of the pinion shafts 166 and the pinion shafts 166 and the planet gears 156 of the planetary gear pair. Each bearing assembly 171 is generally configured to allow relative rotation of the corresponding planet gear 156 about the pinion shaft 166 (e.g., about the planet gear axis 160). For example, the bearing assembly 171 can be disposed between a center ring 172 defining the central bore 164 of the corresponding planet gear 156 and an outer surface 174 of the corresponding pinion shaft 166. In the depicted embodiment, the bearing assembly 171 can include a thrust bearing having a plurality of ball bearings or a roller bearing having a plurality of roller element bearings. The example bearing assembly 171 can include an inner race (not shown) directly or indirectly coupled to the outer surface 174 of the corresponding pinion shaft 166. Further, the example bearing assembly 171 can include an outer race (not shown) directly or indirectly coupled to the center ring 172 of the corresponding planet gear 156. The plurality of ball bearings or roller bearings (not shown) can be disposed circumferentially between the inner race and the outer race about the planet gear axis 160 to allow relative rotation of the inner race and the outer race (and thus the pinion shaft 166 and the planet gear 156) about the planet gear axis 160. However, it should be appreciated that in other embodiments, the bearing assembly 171 can instead have any other suitable form or configuration.

[0078] To provide damping between various rotating and static structures associated with the gear case 150, or to reduce vibrations transmitted to or through the gear case 150, one or more shape memory alloy (“SMA”) dampers can be provided in association with one or more of the sun gear 158, the ring gear 154, the planet gears 156, the carrier 161, the first attachment structure 168, or the second attachment structure 170. As used herein, an SMA damper is a damper that includes at least one shape memory alloy material. Thus, the presently disclosed SMA dampers can reduce vibrations transmitted to the gear case 150 and / or can reduce vibrations transmitted through the gear case 150 to or from at least one of the frame of the engine 10, the first rotating component (e.g., the low pressure shaft 46), the second rotating component (e.g., the rotor assembly 12), or the carrier 161.

[0079] In some embodiments, an SMA damper (e.g., one or more or all of the SMA dampers) can include an SMA material as a primary component in an amount greater than 50 wt.% of the SMA damper. In certain embodiments, an SMA damper can be substantially comprised of an SMA material. SMA materials are generally alloys that can recover their original shape after being deformed. For example, SMA materials can define a hysteresis effect, in which a loading path on a stress-strain graph is different than an unloading path on the stress-strain graph. Thus, compared to traditional elastic materials, SMA materials can provide improved hysteresis damping. Moreover, SMA materials can serve as lightweight, solid-state alternatives to traditional actuators. For example, certain SMA materials can be heated to restore a deformed SMA to its pre-deformed shape. SMA materials can also provide varying stiffness in a predetermined manner in response to certain temperature ranges. The stiffness change of a shape memory alloy is due to a temperature-dependent solid-state microstructure phase change that enables the alloy to change from one physical shape to another. The stiffness change of an SMA material can be created by processing and annealing a preform of the alloy at a temperature equal to or above the temperature at which the solid-state microstructure phase change of the shape memory alloy occurs. The temperature at which this phase change occurs is often referred to as the critical temperature or transformation temperature of the alloy. In the manufacture of SMA dampers that are intended to change stiffness during operation of the gearbox 150, the SMA dampers can be formed to have one operating stiffness (e.g., a first stiffness) below the transformation temperature, and another operating stiffness (e.g., a second stiffness) equal to or above the transformation temperature.

[0080] Some shape memory alloys used herein feature temperature-dependent phase changes. These phases include a martensite phase and an austenite phase. The martensite phase generally refers to the lower temperature phase. While the austenite phase generally refers to the higher temperature phase. The martensite phase is generally more deformable, while the austenite phase is generally less deformable. When a shape memory alloy is in the martensite phase and is heated above a certain temperature, the shape memory alloy begins to transform to the austenite phase. The temperature at which this phenomenon begins is referred to as the austenite start temperature (As). The temperature at which this phenomenon ends is referred to as the austenite finish temperature (Af). When a shape memory alloy in the austenite phase is cooled, it begins to transform to the martensite phase. The temperature at which this transformation begins is referred to as the martensite start temperature (Ms). The temperature at which the transformation to the martensite phase ends is referred to as the martensite finish temperature (Mf). As used herein, the term “transformation temperature” without any further qualifier can refer to either the martensite transformation temperature or the austenite transformation temperature. Additionally, “below the transformation temperature” without the qualifier “start temperature” or “finish temperature” generally refers to a temperature below the martensite finish temperature, and “above the transformation temperature” without the qualifier “start temperature” or “finish temperature” generally refers to a temperature above the austenite finish temperature.

[0081] In some embodiments, the SMA damper can define a first stiffness at a first temperature and a second stiffness at a second temperature, where the second temperature is different than the first temperature. Further, in some embodiments, one of the first or second temperatures is below the transformation temperature, and the other can be equal to or above the transformation temperature. Thus, in some embodiments, the first temperature can be below the transformation temperature and the second temperature can be equal to or above the transformation temperature. While in some other embodiments, the first temperature can be equal to or above the transformation temperature and the second temperature can be below the transformation temperature. Further, various SMA dampers described herein can be configured to have different first stiffnesses and different second stiffnesses at the same first and second temperatures.

[0082] Non-limiting examples of SMA that can be suitable for forming various SMA dampers described herein can include nickel-titanium (NiTi) and other nickel-titanium based alloys, such as nickel-titanium-hafnium (NiTiHf) and nickel-titanium-palladium (NiTiPd). However, it should be appreciated that other SMA materials can be equally suitable for the current disclosure. For example, in certain embodiments, the SMA material can include nickel-aluminum based alloys, copper-aluminum-nickel alloys, or alloys containing zinc, zirconium, copper, gold, platinum, and / or iron. The alloy composition can be selected to provide a desired stiffness effect for the application, such as but not limited to damping capability, transformation temperature and strain, strain hysteresis, yield strength (of the martensite and austenite phases), oxidation and hot corrosion resistance, ability to change shape through repeated cycling, ability to exhibit one-way or two-way shape memory effect, and / or many other engineering design criteria. Suitable shape memory alloy compositions that can be employed with embodiments of the present disclosure can include, but are not limited to, NiTi, NiTiHf, NiTiPt, NiTiPd, NiTiCu, NiTiNb, NiTiVd, TiNb, CuAlBe, CuZnAl, and some iron-based alloys. In some embodiments, a NiTi alloy having a transformation temperature between 5°C and 150°C is used. The NiTi alloy can change from austenite to martensite upon cooling.

[0083] Further, the SMA material can also exhibit superelasticity. Superelasticity can generally be characterized by recovery of large strains, possibly with some dissipation. For example, the martensite and austenite phases of the SMA material can respond to mechanical stresses as well as temperature-induced phase changes. For example, the SMA can be loaded in the austenite phase (i.e., above a certain temperature). Thus, when a critical stress is reached, the material can begin to transform to the (twinning) martensite phase. Upon continued loading and assuming isothermal conditions, the (twinning) martensite can begin to detwin, allowing the material to experience plastic deformation. If unloading occurs before plasticity, the martensite typically transforms back to austenite, and the material can recover its original shape by creating hysteresis.

[0084] It should be appreciated that the damping provided by the various SMA dampers can be a combination of the damping provided by the SMA dampers and other structures of the gear case 150. For example, the damping provided by the first attachment structure 168, the second attachment structure 170, the carrier 161, other dampers (such as those associated with the bearing assembly 171 and / or any other components of the gear case 150, and / or those associated with such a gear case) can be a combination of the damping provided by the SMA dampers and any of the above-mentioned elements associated with the gear case 150.

[0085] The various SMA dampers disclosed herein can be in an unstressed state prior to assembly of the SMA dampers within or in association with the gear case 150. Further, the SMA dampers can be in a pre-stressed state after assembly or arrangement of the SMA dampers relative to the gear case 150. For example, the SMA dampers can be in a pre-stressed state in compression after assembly or arrangement relative to the gear case 150.

[0086] In some embodiments, a single SMA damper or some or all of the SMA dampers can be in a pre-strained or pre-stressed condition (e.g., a pre-stressed state). The SMA dampers in a pre-stressed condition can shift the hysteresis cycle of the SMA dampers to a different range of stresses than that of a non-pre-stressed SMA damper (e.g., when the SMA damper is in an unstressed state). Pre-stressing further serves to maximize the damping function of the SMA dampers, such that the material is operating at the maximum stress generated. More specifically, placing the SMA dampers in a pre-stressed position or state can allow the dampers to enter a hysteresis bending state without requiring a relatively large amount of displacement. For example, in certain embodiments, the various SMA dampers disclosed herein can be pre-stressed between 70 GPa and 150 GPa. Further, it should be appreciated that in embodiments including more than one SMA damper, the SMA dampers can be pre-stressed to the same or approximately the same stress or strain. Additionally or alternatively, however, one or more of the SMA dampers can be pre-stressed or pre-strained to a different degree in order to provide an appropriate amount of damping for the position or condition of the particular SMA damper.

[0087] Generally, the exemplary embodiments of the gear case 150, various components of the gear case 150 or various components associated with the gear case 150, and / or the SMA damper described herein can be manufactured or formed using any suitable process. For example, the SMA damper or components thereof can be stamped or formed via laser electrical discharge machining (EDM), milling, etc. However, in accordance with aspects of the present subject matter, the SMA damper can be formed using an additive manufacturing process (e.g., a 3D printing process) or via casting. The use of such processes can allow the SMA damper to be formed integrally, and / or integrally with other components of the gear case 150 or other components associated with the gear case 150, as a single unitary component, or as any suitable number of sub-components. Forming the SMA damper via additive manufacturing can allow such dampers to be formed integrally and to include a variety of features that are not possible when using existing manufacturing methods. For example, the additive manufacturing methods described herein can enable SMA dampers having any suitable size and shape to be manufactured with one or more configurations, some of these novel features being described herein.

[0088] Referring again to Figure 5 the exemplary gear case 150, the gear case 150 can include one or more SMA dampers disposed in association with the carrier 161 such that vibrations transmitted through the gear case 150 are at least partially isolated from the frame of the engine 10. Additionally or alternatively, such SMA dampers can at least partially isolate or reduce vibrations transmitted to the gear case 150 that act on the frame of the engine 10. For example, as shown in Figure 5 , the one or more SMA dampers can be configured as bearing dampers 176 disposed in association with one or more bearing assemblies 171 arranged between the planetary gears 156 and the corresponding pinions 166 of the carrier 161. In several embodiments, as described in greater detail below with reference to Figure 6-11 , the bearing dampers 176 can be arranged between the bearing assemblies 171 and the outer surface 174 of the corresponding pinions 166. While described herein as being arranged between the outer surface 174 of the pinions 166 and the associated bearing assemblies 171, it should be understood that such description applies equally to one or more bearing dampers 176 arranged between the bearing assemblies 171 and the central ring 172 of the associated planetary gears 156, additionally or alternatively.

[0089] Referring now to Figure 6 , one exemplary embodiment of a bearing damper is shown that includes features suitable for use with various gear cases, such as the above-referenced Figure 5The gearbox 150 described is made of SMA material. In the depicted embodiment, a bearing damper 176 is positioned or arranged between the outer surface 174 of the countershaft 166 and the inner ring 178 of the associated bearing assembly 171, the inner ring 178 of which is disposed between the countershaft 166 and the center ring 172 of the associated planetary gear 156. For example, the bearing damper 176 may be generally arranged or placed as described above regarding Figure 5 The center hole 164, or the hole or center opening or cavity of any suitable gear used in a gearbox and rotatably supported by a countershaft or the like and associated with a suitable bearing assembly.

[0090] The depicted bearing damper 176 may include two or more SMA members 180 disposed between the outer surface 174 of the countershaft 166 of the planetary carrier 161 and the inner ring 178 of the associated bearing assembly 171. In one embodiment, the SMA members 180 may extend along or approximately along the radial direction R relative to the corresponding planetary gear axis 160. Additionally or alternatively, one or more SMA members 180 may also extend in the circumferential direction C and / or the axial direction A relative to the planetary gear axis 160, such that the SMA members 180 define an angle relative to the radial direction R. The SMA members 180 may generally be configured as a cylindrical or cylindrical body. However, in additional or alternative embodiments, one or more SMA members 180 may define any suitable cross-sectional shape, such as, but not limited to, box-shaped or rectangular, elliptical, any other polygon or polygonal cross-section defining any number of sides, any other suitable shape, or a combination of one or more of the foregoing. Furthermore, it should be understood that each SMA member 180 corresponding to the bearing damper 176 does not need to have the same cross-sectional shape, and the SMA members 180 between two different bearing dampers 176 may include different cross-sectional shapes or combinations of shapes. Additionally, the SMA members 180 may be fixed by friction fitting or coupled to one or both of the outer surface 174 of the countershaft 166 or the inner ring 178 of the associated bearing assembly 171 via fastening (bolts, nuts, rivets, etc.), bonding, welding, or any other suitable means. In various embodiments, one or more SMA members 180 may be integrally formed with one or both of the outer surface 174 of the countershaft 166 or the inner ring 178 of the associated bearing assembly 171.

[0091] Now for reference Figure 7 According to various aspects of this disclosure, it is shown that gearboxes are suitable for a wide range of gearboxes (e.g., those mentioned above). Figure 5 An exemplary embodiment of an additional or alternative bearing damper made of SMA material for a gearbox 150 described herein. Figure 7 The bearing damper 176 is roughly similar to the one mentioned above. Figure 6A bearing damper configuration is described. For example, the bearing damper 176 can be positioned or disposed between an outer surface 174 of the pinion shaft 166 and an inner race 178 of the associated bearing assembly 171 disposed between the pinion shaft 166 and the central ring 172 of the associated planetary gear 156. However, for Figure 7 For the illustrated embodiment, the bearing damper 176 can additionally include an SMA ring 182 disposed within the central bore 164 between the outer surface 174 of the corresponding pinion shaft 166 and the associated bearing assembly 171 (e.g., between the outer surface 174 and the inner race 178 of the bearing assembly 171). In the depicted embodiment, the SMA ring 182 encircles the pinion shaft 166 and thus extends generally in the circumferential direction C relative to the planetary gear axis 160 such that the SMA ring 182 is disposed within the central bore 164 of the planetary gear 156. Accordingly, the SMA ring 182 can provide improved damping between the corresponding pinion shaft 166 and planetary gear 156 pair.

[0092] Figure 7 The bearing damper 176 can generally include an SMA member 180 configured the same or similarly as the SMA member 180 described above with respect to the depicted embodiment of Figure 6 the planetary gear 150. For example, the depicted bearing damper 176 can include a first SMA member 184 extending radially relative to the planetary gear axis 160 between the outer surface 174 of the pinion shaft 166 and the SMA ring 182. Similarly, the depicted bearing damper 176 can include a second SMA member 186 extending radially relative to the planetary gear axis 160 between the SMA ring 182 and the inner race 178 of the bearing assembly 171. It should be appreciated that one or more of the first and / or second SMA members 184, 186 can be fixed via a friction fit or integrally formed with or coupled to the SMA ring 182 via fastening (bolt, nut, rivet, etc.), bonding, welding, or any other suitable manner. Additionally or alternatively, it should be appreciated that one or more bearing dampers 176 need not include both the first SMA member 184 and the second SMA member 186. For example, the SMA ring 182 can be disposed in contact with one of the outer surface 174 of the pinion shaft 166 or the inner race 178 of the bearing assembly 171. In such embodiments, the SMA ring 182 can be fixed to the respective outer surface 174 or inner race 178 via a friction fit or integrally formed with or coupled to the respective outer surface 174 or inner race 178 via fastening (bolt, nut, rivet, etc.), bonding, welding, or any other suitable manner.

[0093] Reference is now made to Figure 8, various gearboxes (e.g., the gearbox 150 described above with respect to Figure 5 One exemplary embodiment of an additional or alternative bearing damper including SMA material suitable for use in various gearboxes (e.g., the gearbox 150 described above with respect to Figure 8 Figure 6 and 7 may be positioned or arranged between the outer surface 174 of the layshaft 166 and the inner race 178 of the associated bearing assembly 171 disposed between the layshaft 166 and the central ring 172 of the associated planetary gear 156. However, for the embodiment shown, the bearing damper 176 can include a plurality of closed SMA elements 188. Figure 8

[0094] The closed SMA elements 188 described herein generally refer to a damping element defining a shape that is closed in a plane perpendicular to the axial direction A with respect to the planetary gear axis 160. For example, as shown in the exemplary embodiment of Figure 8 , the closed SMA elements 188 can define a box or rectangular shape in a plane defined along the radial direction R and the circumferential direction C. However, in additional or alternative embodiments, one or more of the closed SMA elements 188 can define any suitable cross-sectional shape, such as a circle, an ellipse, any other polygon defining any number of sides, or a cross-section of a polygon, or a combination of one or more of the foregoing. In the depicted embodiment, the closed SMA elements 188 are fixed to the inner race 178 of the bearing assembly 171 and frictionally fit to the outer surface 174 of the layshaft 166. The closed SMA elements 188 can be fixed the same as or similar to the SMA members 180 described above with respect to Figure 6 and 7 In additional or alternative embodiments, one or more of the SMA elements 188 can frictionally fit to the outer surface 174 and the inner race 178. Further, in additional or alternative embodiments, one or more of the closed SMA elements 188 can be fixed to both the outer surface 174 and the inner race 178.

[0095] Referring now to Figure 9 , various gearboxes (e.g., the gearbox 150 described above with respect to Figure 5 One exemplary embodiment of an additional or alternative bearing damper including SMA material suitable for use in various gearboxes (e.g., the gearbox 150 described above with respect to Figure 9 The bearing damper 176 can be generally similar to the bearing damper described above with respect to Figure 6-8 ​​A bearing damper configuration is described. For example, the bearing damper 176 can be positioned or disposed between an outer surface 174 of the pinion shaft 166 and an inner race 178 of an associated bearing assembly 171 disposed between the pinion shaft 166 and a central ring 172 of the associated planetary gear 156. However, for Figure 9 For the illustrated embodiment, the bearing damper 176 can include a plurality of SMA plates 190, such as corrugated SMA plates. For example, as illustrated, Figure 9 The illustrated bearing damper 176 can include a plurality of SMA plates 190 stacked in a radial direction R relative to the planetary gear axis 160 between the outer surface 174 of the corresponding pinion shaft 166 and the inner race 178 of the corresponding bearing assembly 171. Thus, the SMA plates 190 can extend in a circumferential direction C relative to the central bore 164 and the planetary gear axis 160 of the associated planetary gear 156.

[0096] In Figure 9 For the illustrated embodiment, the bearing damper 176 can include two or more groups 192 of SMA plates 190 disposed at a plurality of locations in the space between the outer surface 174 of the pinion shaft 166 and the inner race 178 of the associated bearing assembly 171. Thus, the groups 192 of SMA plates 190 can be circumferentially inscribed within the central bore 164 of the associated planetary gear 156 inward of the outer surface 174 of the corresponding pinion shaft 166. However, in additional or alternative embodiments, one or more of the SMA plates 190 can extend substantially along the outer surface 174 of the pinion shaft 166 and completely around the outer surface 174 of the pinion shaft 166. For example, at least one of the SMA plates 190 (such as all of the SMA plates 190) can extend completely along the circumferential direction C to form a ring. Although generally described as a corrugated plate, in one example, it should be appreciated that the SMA plates 190 can define any suitable shape or cross-sectional shape. For example, in additional or alternative embodiments, at least one of the SMA plates 190 can be configured as a leaf spring. Further, one or more of the SMA plates 190 can be configured to bend radially inward or radially outward relative to the planetary gear axis 160 at respective ends of the SMA plate 190. The SMA plates 190 can be fastened, coupled, or secured within the central bore 164 the same or similarly as the SMA members 180 described above with respect to Figure 6 and 7 the SMA elements 188 described above with respect to Figure 8

[0097] Referring now to Figure 10 one exemplary embodiment of an additional or alternative bearing damper including SMA material suitable for use in various gearboxes, such as the gearbox 150 described above with respect to Figure 5 Figure 10 ​​The bearing damper 176 is roughly similar to the one mentioned above. Figure 6-9 The bearing damper configuration is described above. For example, the bearing damper 176 may be positioned or arranged between the outer surface 174 of the countershaft 166 and the inner ring 178 of the associated bearing assembly 171, the inner ring 178 of which is disposed between the countershaft 166 and the central ring 172 of the associated planetary gear 156. However, for Figure 9 In the illustrated embodiment, the bearing damper 176 may include a plurality of SMA springs 194. For example, as shown, the bearing assembly 171 may include two or more SMA springs 194 disposed between the outer surface 174 of the countershaft 166 of the planetary carrier 161 and the inner ring 178 of the associated bearing assembly 171. In one embodiment, the SMA springs 194 may extend along or approximately along the radial direction R relative to the corresponding planetary gear axis 160. The SMA springs 194 may be related to the above description regarding... Figure 6 and 7 The SMA component 180 described above, regarding Figure 8 The SMA element 188 described above, and / or the above regarding Figure 9 The SMA plate 190 described is fastened, connected or fixed in the center hole 164 in the same or similar manner.

[0098] Now for reference Figure 11 According to various aspects of this disclosure, it is shown that gearboxes are suitable for a wide range of gearboxes (e.g., those mentioned above). Figure 5 An exemplary embodiment of an additional or alternative bearing damper made of SMA material for a gearbox 150 described herein. Figure 11 The bearing damper 176 is roughly similar to the one mentioned above. Figure 6-10 The described bearing damper configuration. For example, the bearing damper 176 may be positioned or arranged between the outer surface 174 of the countershaft 166 and the inner ring 178 of the associated bearing assembly 171, the inner ring 178 of which is disposed between the countershaft 166 and the central ring 172 of the associated planetary gear 156. However, for Figure 10In the illustrated embodiment, the bearing damper 176 can include an SMA mesh ring 196 arranged between the outer surface 174 of the pinion shaft 166 of the planet carrier 161 and the inner race 178 of the associated bearing assembly 171 within the central bore 164. In the depicted embodiment, the SMA mesh ring 196 encircles the pinion shaft 166 and thus extends generally in the circumferential direction C relative to the planetary gear axis 160, such that the SMA mesh ring 196 is arranged within the central bore 164 of the planetary gear 156. It will be appreciated that the SMA mesh ring 196 can be continuous along the circumferential direction C or can be segmented such that the SMA mesh ring 196 includes two or more mesh segments arranged end-to-end with respect to the circumferential direction C in order to encircle the outer surface 174 of the corresponding pinion shaft 166. The SMA mesh ring 196 can be fastened, coupled, or fixed within the central bore 164 identically or similarly to the SMA member 180 described above with respect to Figure 6 and 7 the SMA element 188 described above with respect to Figure 8 the SMA plate 190 described above with respect to Figure 9 and / or the SMA spring 194 described above with respect to Figure 10 Additionally or alternatively, the SMA mesh ring 196 can be integrally formed with one or both of the outer surface 174 of the pinion shaft 166 or the inner race 178.

[0099] Referring now to Figure 12 , exemplary embodiments of an additional or alternative gear case of a gas turbine engine in accordance with aspects of the present disclosure are provided. Figure 12 The gear case 150 can be generally similar to the gear case configurations described above with respect to Figure 4 and 5 For example, the gear case 150 can be configured as a reverse rotating star gear case 150 and can be incorporated into the exemplary engine 10 discussed above with respect to Figure 1-3 or, alternatively, can be incorporated into any other suitable gas turbine engine (e.g., a non-ducted rotor engine of a different configuration, a ducted rotor engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.), or any other suitable internal combustion engine utilizing a gear case, etc. The gear case 150 will be generally described with respect to the power gear case 56, but the following disclosure can equally apply to any other gear case (e.g., the accessory gear case 66) utilizing any other suitable epicyclic gear case configuration (e.g., a planetary gear case configuration or a differential gear case configuration). The gear case 150 can generally include a first attachment structure 168, a sun gear 158, a second attachment structure 170, a ring gear 154, a plurality of planetary gears 156 arranged between the sun gear 158 and the ring gear 154, a planet carrier 161 including a pinion shaft 166, and one or more bearing assemblies 171. However, for the sake of brevity, the following disclosure will be described with respect to the power gear case 56.Figure 12 In the illustrated embodiment, the gear case 150 can include an SMA isolation damper 198 coupled to the planet carrier 161 between the planet carrier 161 and a frame and / or ground structure 162 of the engine 10.

[0100] Such an SMA isolation damper 198 can at least partially isolate the planet carrier 161 and vibrations transmitted through the planet carrier 161 from the frame of the engine 10. Additionally or alternatively, such an SMA isolation damper 198 can at least partially isolate or reduce vibrations transmitted to the gear case 150 that act on the frame of the engine 10. For example, the SMA isolation damper 198 can at least partially isolate or reduce vibrations transmitted to the gear case 150 that are caused by the rotation of the planet carrier 161 and / or the rotation of the sun gear 160. Figure 12 For example embodiments of the gear case 150, the SMA isolation damper 198 is disposed between segments of the planet carrier 161 so as to dampen vibrations transmitted between the frame of the engine 10 and the gear case 150. For example, as illustrated, the SMA isolation damper 198 is depicted as being placed between the countershaft 166 of the planet carrier 161 and the remaining structure of the planet carrier 161. However, in other embodiments, the SMA isolation damper 198 can be disposed between any suitable segment or portion of the planet carrier 161 and / or between the planet carrier 161 and the ground structure 162 or frame of the engine 10.

[0101] The SMA isolation damper 198 can generally be configured as a segment of the planet carrier 161 or another type of damper, such as a shock absorber or similar structure formed of an SMA material as described herein, known to those of ordinary skill in the art. Further, the SMA isolation damper 198 can be secured between segments of the planet carrier 161 or between the planet carrier 161 and the ground structure 162 or frame using one or more of fastening (bolts, nuts, rivets, etc.), adhesion, welding, or any other suitable means. Additionally or alternatively, the SMA isolation damper 198 can be integrally formed with one or more segments of the planet carrier 161, the ground structure 162 of the engine 10, and / or the frame of the engine 10. While described with respect to a planet carrier 161 secured to a ground structure 162 or frame of the engine 10, it should be understood that such an SMA isolation damper 198 is equally applicable to embodiments of the gear case in which the planet carrier 161 is coupled to a rotating component of the engine 10. Further, the gear case 150 can generally include an SMA isolation damper 198 associated with multiple countershafts 166 of the planet carrier 161, such as all of the countershafts 166.

[0102] Referring now to Figure 13 , additional or alternative exemplary embodiments of a gear case of a gas turbine engine in accordance with aspects of the present disclosure are provided. Figure 13 The gear case 150 of the gas turbine engine 10 can generally be similar to the gear case 150 described above with respect to Figure 4 , 5The gear case 150 can be configured as a reverse rotating epicyclic gear case 150 and can incorporate the above-described gear case configurations of Figs. 1-12. For example, the gear case 150 can be configured as a reverse rotating epicyclic gear case 150 and can incorporate the above-described gear case configurations of Figs. 1-12 with respect to the power gear case 56, or alternatively, any other suitable gas turbine engine (e.g., a non-duct-rotor engine of different configuration, a duct-rotor engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.), or any other suitable internal combustion engine utilizing a gear case, etc. The gear case 150 will be generally described with respect to the power gear case 56, but the following disclosure can equally apply to any other gear case (e.g., the accessory gear case 66) utilizing any other suitable epicyclic gear case configuration (e.g., a planetary gear case configuration or a differential gear case configuration). Figure 1-3 The exemplary engine 10 discussed (e.g., as the power gear case 56), or alternatively, can incorporate any other suitable gas turbine engine (e.g., a non-duct-rotor engine of different configuration, a duct-rotor engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.), or any other suitable internal combustion engine utilizing a gear case, etc. The gear case 150 will be generally described with respect to the power gear case 56, but the following disclosure can equally apply to any other gear case (e.g., the accessory gear case 66) utilizing any other suitable epicyclic gear case configuration (e.g., a planetary gear case configuration or a differential gear case configuration).

[0103] The gear case 150 can generally include a first attachment structure 168, the sun gear 158, a second attachment structure 170, the ring gear 154, a plurality of planet gears 156 arranged between the sun gear 158 and the ring gear 154, a planet carrier 161 including a countershaft 166, and one or more bearing assemblies 171. However, for the exemplary embodiment shown, the gear case 150 can include an SMA extension damper 204 disposed in association with one or both of the first attachment structure 168 or the second attachment structure 170 (not shown). Thus, although the following embodiments are described with respect to the second attachment structure 170, it should be understood that such SMA extension dampers 204 can equally apply for use with the first attachment structure 168. Moreover, although described with respect to an attachment structure coupled to a rotating component of the engine 10, it should be understood that such SMA extension dampers 204 can equally apply to an attachment structure configured to be coupled to the ground structure 162 or frame of the engine 10. Figure 13 The gear case 150 can be configured as a reverse rotating epicyclic gear case 150 and can incorporate the above-described gear case configurations of Figs. 1-12. For example, the gear case 150 can be configured as a reverse rotating epicyclic gear case 150 and can incorporate the above-described gear case configurations of Figs. 1-12 with respect to the power gear case 56, or alternatively, any other suitable gas turbine engine (e.g., a non-duct-rotor engine of different configuration, a duct-rotor engine, a turbofan engine, a turboshaft engine, a turboprop engine, a turbojet engine, etc.), or any other suitable internal combustion engine utilizing a gear case, etc. The gear case 150 will be generally described with respect to the power gear case 56, but the following disclosure can equally apply to any other gear case (e.g., the accessory gear case 66) utilizing any other suitable epicyclic gear case configuration (e.g., a planetary gear case configuration or a differential gear case configuration).

[0104] In Figure 13In exemplary embodiments of the second attachment structure 170 includes a first segment 200 coupled to or integrally formed with the sun gear 158. Further, the second attachment structure 170 can include a second segment 202 configured to be coupled to a rotating component of the engine 10, such as the rotor assembly 12 of the engine 10. The first segment 200 and the second segment 202 can be integrally formed together or can be coupled together. Further, at least a portion of the first segment 200 and at least a portion of the second segment 202 of the second attachment structure 170 can extend parallel to or at least partially parallel to one another. Further, such parallel extending portions can be displaced from one another in a direction perpendicular to such parallel extending or partially extending portions. Thus, for example, the depicted second attachment structure 170 can define an approximate U-shaped cross-section defined by the first segment 200 and the second segment 202 of the second attachment structure 170. Such an arrangement can result in a flexible second attachment structure 170 that provides a degree of damping between the ring gear 154 and the rotating structure coupled to the attachment structure 170. However, in additional or alternative embodiments, it should be appreciated that the second attachment structure 170 including the first segment 200 and the second segment 202 can define any suitable arrangement or shape in order to provide a degree of damping to the ring gear 154. However, in certain embodiments of the gear case 150 and / or under certain operating conditions of the gear case 150, the damping provided by such a flexible attachment structure 170 can not be sufficient to reduce vibrations transmitted between the ring gear 154 and the rotating component of the engine 10.

[0105] Thus, as Figure 13 In exemplary embodiments as depicted, the gear case 150 can include an SMA extension damper 204 disposed in association with the second attachment structure 170 in order to provide improved damping between the ring gear 154 and the corresponding rotating component of the engine 10. Thus, various embodiments of the SMA extension damper 204 can further reduce vibrations transmitted between the ring gear 154 of the gear case 150 and the associated rotating component of the engine 10 as compared to the flexible second attachment structure 170 alone. Generally, the SMA extension damper 204 can be coupled between the first segment 200 and the second segment 202 of the second attachment structure 170 in order to increase the damping provided. For example, the SMA extension damper 204 can extend at least partially perpendicular to one or both of the first segment 200 and the second segment 202. As one example, as depicted, the SMA extension damper 204 can extend at least partially perpendicular to the first segment 200 and the second segment 202 of the second attachment structure 170. Thus, the SMA extension damper 204 can extend at least partially perpendicular to the first segment 200 and the second segment 202 of the second attachment structure 170 in order to increase the damping provided between the ring gear 154 and the corresponding rotating component of the engine 10. Figure 13As shown, the SMA extension damper 204 can extend within the U-shape of this second attachment structure 170 between the first segment 200 and the second segment 202. Furthermore, the SMA extension damper 204 can be secured between the segments 200, 202 of the second attachment structure 170 using one or more of the following methods: fastening (bolts, nuts, rivets, etc.), bonding, welding, or any other suitable means. Additionally or alternatively, the SMA extension damper 204 can be integrally formed with one or both segments 200, 202 of the second attachment structure 170.

[0106] Now for reference Figure 14 Exemplary embodiments of an additional or alternative gearbox for a gas turbine engine according to aspects of this disclosure are provided. Figure 14 The gearbox 150 is roughly similar to the one mentioned above. Figure 4 , 5 The gearbox configuration described in 12 and 13. For example, gearbox 150 can be configured as a counter-rotating planetary gearbox 150 and can be incorporated into the above references. Figure 1-3 The exemplary engine 10 discussed (e.g., as power gearbox 56), or alternatively, any other suitable gas turbine engine (e.g., a non-inline rotary engine, inline rotary engine, turbofan engine, turboshaft engine, turboprop engine, turbojet engine, etc., of different configurations), or any other suitable internal combustion engine utilizing a gearbox, etc., may be incorporated. Gearbox 150 will be described generally with respect to power gearbox 56, but the following disclosure is equally applicable to any other gearbox (e.g., accessory gearbox 66) utilizing any other suitable rotary gearbox configuration (e.g., planetary gearbox configuration or differential gearbox configuration).

[0107] Gearbox 150 typically includes a first attachment structure 168, a sun gear 158, a second attachment structure 170, a ring gear 154, a plurality of planetary gears 156 arranged between the sun gear 158 and the ring gear 154, a planet carrier 161 including a countershaft 166, and one or more bearing assemblies 171. However, for Figure 14 In the illustrated embodiment, gearbox 150 may include an SMA external damper 206 associated with planet carrier 161. However, although the following embodiments are described with respect to planet carrier 161, it should be understood that such an SMA external damper 206 is equally applicable to use with the first attachment structure 168 and / or the second attachment structure 170. Furthermore, while the planet carrier 161 is described with respect to a static structure coupled to engine 10, it should be understood that such an SMA external damper 206 can also be applied to planet carrier 161 configured to be coupled to a rotating structure (e.g., rotor assembly 12) of engine 10.

[0108] existFigure 14 In exemplary embodiments of the present subject matter, the SMA external damper 206 can be affixed or coupled to an outer surface of the planet carrier 161 so as to provide improved damping between the planetary gears 156 and the frame and / or ground structure 162 of the engine 10. Thus, various embodiments of the SMA external damper 206 can further reduce vibrations transmitted between the planetary gears 156 of the gear box 150 and the frame of the engine 10 as compared to the planet carrier 161 alone. Generally, the SMA external damper 206 can be positioned on such an outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 so as to increase the damping provided. For example, the SMA external damper 206 can be positioned on a portion of the planet carrier 161 as shown in FIG. 171. However, in alternative embodiments, the SMA external damper 206 can be positioned on the entire outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 of the engine 10. Additionally or alternatively, the SMA external damper 206 can also be applied to the outer surface 174 of one or more counter shafts 166 of the planet carrier 161. Generally, the SMA external damper 206 can include one or more strips, pieces, segments, etc. affixed to the planet carrier 161 using one or more of fastening (bolts, nuts, rivets, etc.), adhesion, welding, or any other suitable means. Additionally or alternatively, the SMA external damper 206 can be integrally formed with the planet carrier 161. In at least one embodiment, a portion or all of the SMA external damper 206 can include a coating spray applied to at least a segment of the outer surface of the planet carrier 161. Further, as described in more detail below with respect to Figure 15 In exemplary embodiments of the present subject matter, the SMA external damper 206 can be affixed or coupled to an outer surface of the planet carrier 161 so as to provide improved damping between the planetary gears 156 and the frame and / or ground structure 162 of the engine 10. Thus, various embodiments of the SMA external damper 206 can further reduce vibrations transmitted between the planetary gears 156 of the gear box 150 and the frame of the engine 10 as compared to the planet carrier 161 alone. Generally, the SMA external damper 206 can be positioned on such an outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 so as to increase the damping provided. For example, the SMA external damper 206 can be positioned on a portion of the planet carrier 161 as shown in FIG. 171. However, in alternative embodiments, the SMA external damper 206 can be positioned on the entire outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 of the engine 10. Additionally or alternatively, the SMA external damper 206 can also be applied to the outer surface 174 of one or more counter shafts 166 of the planet carrier 161. Generally, the SMA external damper 206 can include one or more strips, pieces, segments, etc. affixed to the planet carrier 161 using one or more of fastening (bolts, nuts, rivets, etc.), adhesion, welding, or any other suitable means. Additionally or alternatively, the SMA external damper 206 can be integrally formed with the planet carrier 161. In at least one embodiment, a portion or all of the SMA external damper 206 can include a coating spray applied to at least a segment of the outer surface of the planet carrier 161. Further, as described in more detail below with respect to

[0109] Reference is now made to Figure 15 FIG. 171 illustrates one embodiment of the SMA external damper 206 of the present subject matter being cryogenically fitted to an outer surface of the planet carrier 161 in a cryogenic fitting process 207, in accordance with aspects of the present subject matter. Figure 14 In exemplary embodiments of the present subject matter, the SMA external damper 206 can be affixed or coupled to an outer surface of the planet carrier 161 so as to provide improved damping between the planetary gears 156 and the frame and / or ground structure 162 of the engine 10. Thus, various embodiments of the SMA external damper 206 can further reduce vibrations transmitted between the planetary gears 156 of the gear box 150 and the frame of the engine 10 as compared to the planet carrier 161 alone. Generally, the SMA external damper 206 can be positioned on such an outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 so as to increase the damping provided. For example, the SMA external damper 206 can be positioned on a portion of the planet carrier 161 as shown in FIG. 171. However, in alternative embodiments, the SMA external damper 206 can be positioned on the entire outer surface of the planet carrier 161 between the counter shaft 166 and the ground structure 162 of the engine 10. Additionally or alternatively, the SMA external damper 206 can also be applied to the outer surface 174 of one or more counter shafts 166 of the planet carrier 161. Generally, the SMA external damper 206 can include one or more strips, pieces, segments, etc. affixed to the planet carrier 161 using one or more of fastening (bolts, nuts, rivets, etc.), adhesion, welding, or any other suitable means. Additionally or alternatively, the SMA external damper 206 can be integrally formed with the planet carrier 161. In at least one embodiment, a portion or all of the SMA external damper 206 can include a coating spray applied to at least a segment of the outer surface of the planet carrier 161. Further, as described in more detail below with respect to

[0110] like Figure 15 As illustrated in exemplary process 207, in the first step (208) of the cryogenic adaptation process 207, the planetary carrier 161 may be cooled to reduce its size. In the second step (210), the SMA external damper 206 may be heated to increase its size. In such an embodiment, the SMA external damper 206 may be constructed as a tube or a sheath. However, it should be understood that this cryogenic adaptation process 207 only needs to include one of steps 208 and 210. In the third step (211), the planetary carrier 161 is inserted into the SMA external damper 206. The third step 211 also includes at least one of allowing the planetary carrier 161 to heat up, expand, or allowing the SMA external damper 206 to cool down, or contract. Therefore, the cryogenic adaptation process 207 can provide a more robust frictional fit between the SMA external damper 206 and the planetary carrier 161. Furthermore, it should be understood that this cryogenic adaptation treatment 207 can also apply prestress to the SMA external damper 206 as described herein.

[0111] Embodiments of this disclosure also relate to the use of SMA dampers associated with a fluid transport system provided in association with a gas turbine engine. Reference is now made to... Figure 16 An exemplary fluid transfer system for a gas turbine engine according to an exemplary embodiment of the present disclosure is provided. The exemplary fluid transfer system 300 may be incorporated herein by reference. Figure 1-3 The exemplary engine 10 discussed, or alternatively, may be incorporated into any other suitable gas turbine engine (e.g., non-inline rotary engine, inline rotary engine, turbofan engine, turboshaft engine, turboprop engine, turbojet engine, etc. of different configurations), or any other suitable internal combustion engine utilizing an applicable fluid transport system that can benefit from the vibration damping of the associated engine.

[0112] like Figure 16 As shown, the fluid transport system 300 may include one or more fluid conduits, for example... Figure 16The fluid transport system 300 includes a first fluid conduit 214 and a second fluid conduit 219. However, it should be understood that the fluid transport system 300 may include additional fluid conduits. The fluid conduits described herein generally include pipes configured to transport at least one of fuel, air, or oil between locations of the engine 10 to power the engine 10, cool components of the engine 10, or lubricate components of the engine 10, respectively. Furthermore, the fluid conduits may include segments (e.g., a first segment 216 and a second segment 218 of the first fluid conduit 214). The segments of the fluid conduits may be joined at one or more junctions 220 connecting the segments of the fluid conduits, such that the segments of the fluid conduits are fluidly connected to each other. Additionally, the fluid transport system 300 may include a plurality of clamps 222 configured to attach a corresponding fluid conduit or segment of the fluid conduit to the frame of the engine 10. To provide damping or reduce vibrations transmitted from the frame of the engine 10 to or through the fluid conduits, one or more SMA dampers may be provided associated with one or more fluid conduits and / or segments of the fluid conduits. Therefore, the currently disclosed SMA damper for the fluid transport system 300 can reduce vibrations transmitted from the engine frame to the fluid ducts, can reduce vibrations transmitted through associated fluid ducts, and / or can reduce vibrations transmitted between different fluid ducts or sections of fluid ducts.

[0113] Now for reference Figure 17 An embodiment of a dual-adaptor SMA damped fluid conduit is shown according to aspects of this disclosure. The disclosed dual-adaptor SMA damped fluid conduit 228 can be incorporated into the references above. Figure 16 The exemplary fluid transport system 300 described herein, or alternatively, may be incorporated into any other suitable fluid transport system associated with a suitable gas turbine engine. As shown, the fluid conduit (e.g., the first fluid conduit 214) may typically utilize suitable cryogenic adaptation treatments (e.g., as described above regarding...). Figure 15 The described cryogenic adaptation process 207 is cryogenically adapted to the SMA tube or sheath (SMA tube 224). A single-adaptor SMA damping fluid conduit can be produced by this single cryogenic adaptation process. Furthermore, it may be desirable to provide an external outer tube 226 for the single-adaptor SMA damping fluid conduit to provide additional protection for the internal fluid conduit 214 and the SMA tube 224 surrounding it. Therefore, as... Figure 17 As shown, the resulting single-adaptor SMA damping fluid conduit can be cryogenically adapted to the outer tube 226 using the same or similar cryogenic adaptation treatment to produce a double-adaptor SMA damping fluid conduit 228.

[0114] Now for reference Figure 18 Additional or alternative embodiments of the dual-adapter SMA damped fluid conduit are shown according to aspects of this subject matter. Figure 18The dual-adapter SMA damped fluid conduit 228 can typically be used with the fluid conduit mentioned above. Figure 17 Manufactured using the same or similar low-temperature adaptation treatments. However, Figure 18 The dual-adaptor SMA damping fluid conduit 228 includes multiple SMA inserts 230 instead of Figure 17 SMA tube 224. Although Figure 18 The SMA insert 230 is typically defined in a trapezoidal shape; however, it should be understood that the SMA insert 230 may be defined in any suitable shape or cross-sectional shape. For example, the SMA insert may be constructed to be the same as or similar to any embodiment of the SMA member 180, SMA element 188, SMA plate 190, SMA spring 194 and / or SMA loop 196 or a segment of the SMA loop 196 as described herein.

[0115] Combination Figure 19 Return to reference Figure 16 In additional or alternative embodiments, one or more SMA dampers may be associated with fluid conduits to reduce vibrations transmitted between the engine frame and the fluid conduits. For example, Figure 19 A clamp for a fluid transfer system configured as an SMA clamp is shown. Figure 19 The disclosed SMA fixture 232 can be incorporated into the reference above. Figure 16 The exemplary fluid transport system 300 described herein, or any other suitable fluid transport system associated with a suitable gas turbine engine, may be incorporated. For example, as shown, a clamp 222 (SMA clamp 232) formed of SMA material may be used to connect fluid conduits (e.g., first fluid conduit 214) to the grounding structure 162 and / or frame of the engine 10.

[0116] Now for reference Figure 16 Additionally or alternatively, the fluid transport system 300 may include one or more SMA bridges 234 connected between different fluid conduits (e.g., a first fluid conduit 214 and a second fluid conduit 219) or between segments of the same fluid conduit (e.g., a first segment 216 and a second segment 218 of the first fluid conduit 214). SMA bridges 234 can generally reduce vibrations transmitted through the fluid transport system 300. Figure 16 The SMA bridge 234 can typically be configured as any suitable element or component extending between the respective fluid conduit or segments of the fluid conduit. For example, one or more SMA bridges 234 can be configured to be the same as or similar to any embodiment of the SMA component 180, SMA element 188, SMA spring 194, or SMA extension damper 204 described herein, or any combination thereof.

[0117] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present invention is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0118] Further aspects of the present invention are provided by the subject matter of the following clauses:

[0119] A epicyclic gearbox configured to be supported by a frame of a gas turbine engine and configured to transfer rotational motion between a first rotating component of the gas turbine engine and a second rotating component of the gas turbine engine, the gearbox comprising: a sun gear located at a center, the sun gear comprising a plurality of teeth; a plurality of planet gears encircling the sun gear, each of the planet gears comprising a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each of the plurality of planet gears; a ring gear encircling the plurality of planet gears, the ring gear comprising a plurality of teeth configured to mesh with the teeth of each of the planet gears such that the ring gear rotates relative to the plurality of planet gears; and at least one shape memory alloy damper disposed in association with at least one of the sun gear, the ring gear, or the plurality of planet gears and configured to reduce vibrations transferred by the epicyclic gearbox to at least one of the frame, the first rotating component, or the second rotating component of the gas turbine engine.

[0120] The epicyclic gearbox of any preceding clause, further comprising: a carrier coupled to each of the plurality of planet gears and configured to be coupled to the frame of the gas turbine engine such that the carrier supports the epicyclic gearbox relative to the frame of the gas turbine engine.

[0121] The epicyclic gearbox of any preceding clause, further comprising: a carrier coupled to each of the plurality of planet gears and configured to be drivingly coupled to the first rotating component of the gas turbine engine.

[0122] The epicyclic gearbox of any preceding clause, further comprising: a planet carrier coupled to each of the plurality of planet gears and configured to be drivingly coupled to the second rotating component of the gas turbine engine.

[0123] The epicyclic gearbox of any preceding clause, wherein the sun gear is configured to be drivingly coupled to the first rotating component of the gas turbine engine.

[0124] The epicyclic gearbox of any preceding clause, wherein the ring gear is configured to be drivingly coupled to a second rotating component of the gas turbine engine.

[0125] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is disposed in association with the planet carrier and is configured such that vibrations transmitted through the epicyclic gearbox are at least partially isolated from the frame of the gas turbine engine.

[0126] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is disposed in association with the planet carrier and is configured such that vibrations transmitted through the epicyclic gearbox are at least partially isolated from the second rotating component of the gas turbine engine.

[0127] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is disposed in association with the planet carrier and is configured such that vibrations transmitted through the epicyclic gearbox are at least partially isolated from the first rotating component of the gas turbine engine.

[0128] The epicyclic gearbox of any preceding clause, wherein each of the plurality of planet gears defines a central bore within a central ring, wherein the planet carrier includes a plurality of pinions, each of the plurality of pinions corresponding to a planet gear of the plurality of planet gears, each pinion extending in an axial direction within the central bore of its corresponding planet gear.

[0129] The epicyclic gearbox of any preceding clause, further comprising: a plurality of bearing assemblies, each of the plurality of bearing assemblies associated with a pinion and planet gear pair, each bearing assembly arranged between the central ring of the corresponding planet gear and an outer surface of the corresponding pinion such that the bearing assembly allows relative rotation of the corresponding planet gear about its corresponding pinion.

[0130] The epicyclic gearbox of any preceding clause, further comprising: a plurality of the at least one shape memory alloy damper configured as bearing dampers.

[0131] The epicyclic gearbox of any preceding Clause, wherein each bearing damper is arranged between the bearing assembly and the outer surface of the associated planet shaft and the planet gear pair of the corresponding planet shaft with respect to the central bore.

[0132] The epicyclic gearbox of any preceding Clause, wherein each bearing damper comprises a plurality of shape memory alloy members extending radially between the outer surface of the corresponding planet shaft and the corresponding bearing assembly of the associated planet shaft and planet gear pair with respect to the central bore.

[0133] The epicyclic gearbox of any preceding Clause, wherein each bearing damper comprises a shape memory alloy ring arranged within the central bore between the outer surface of the planet shaft and the corresponding bearing assembly of the associated planet shaft and planet gear pair.

[0134] The epicyclic gearbox of any preceding Clause, wherein the plurality of shape memory alloy members comprises a first set of shape memory alloy members extending radially from the outer surface of the corresponding planet shaft to the shape memory alloy ring with respect to the central bore.

[0135] The epicyclic gearbox of any preceding Clause, wherein the plurality of shape memory alloy members comprises a second set of shape memory alloy members extending radially from the shape memory alloy ring to the corresponding bearing assembly of the associated planet shaft and planet gear pair with respect to the central bore.

[0136] The epicyclic gearbox of any preceding Clause, wherein the bearing damper comprises a plurality of closed shape memory alloy elements.

[0137] The epicyclic gearbox of any preceding Clause, wherein each of the plurality of closed shape memory alloy elements is arranged between the outer surface of the corresponding planet shaft and the corresponding bearing assembly within the central bore of the planet gear of the associated planet shaft and planet gear pair.

[0138] The epicyclic gearbox of any preceding Clause, wherein at least one bearing damper comprises a plurality of shape memory alloy plates.

[0139] The epicyclic gearbox of any preceding Clause, wherein each bearing damper comprises a plurality of shape memory alloy plates.

[0140] The epicyclic gearbox of any preceding Clause, wherein each of the plurality of shape memory alloy plates extends circumferentially with respect to the central bore of the planet gear and is arranged between the outer surface of the corresponding planet shaft and the corresponding bearing assembly of the associated planet shaft and planet gear pair.

[0141] The epicyclic gearbox of any preceding clause, wherein the at least one bearing damper comprises a shape memory alloy mesh ring disposed between the outer surface of the corresponding pinion and the corresponding bearing assembly of the associated pinion and planetary gear pair.

[0142] The epicyclic gearbox of any preceding clause, wherein each bearing damper comprises a shape memory alloy mesh ring disposed between the outer surface of the corresponding pinion and the corresponding bearing assembly of the associated pinion and planetary gear pair.

[0143] The epicyclic gearbox of any preceding clause, wherein the at least one bearing damper comprises a plurality of shape memory alloy coil springs extending radially relative to the central bore between the outer surface of the corresponding pinion and the corresponding bearing assembly of the associated pinion and planetary gear pair.

[0144] The epicyclic gearbox of any preceding clause, wherein each bearing damper comprises a plurality of shape memory alloy coil springs extending radially relative to the central bore between the outer surface of the corresponding pinion and the corresponding bearing assembly of the associated pinion and planetary gear pair.

[0145] The epicyclic gearbox of any preceding clause, further comprising a shape memory alloy damper of the at least one shape memory alloy damper configured as an isolation damper.

[0146] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the planet carrier and is further configured to be coupled between the planet carrier and the frame of the gas turbine engine.

[0147] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the planet carrier and is further configured to be coupled between the planet carrier and the second rotating component of the gas turbine engine.

[0148] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the planet carrier and is further configured to be coupled between the planet carrier and the first rotating component of the gas turbine engine.

[0149] The epicyclic gearbox of any preceding clause, further comprising a first attachment structure coupled to the sun gear and further configured to be coupled to the first rotating component of the gas turbine engine.

[0150] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the first attachment structure and is further configured to be coupled between the first attachment structure and the first rotating component of the gas turbine engine.

[0151] The epicyclic gearbox of any preceding clause, wherein the sun gear is configured to be coupled to the frame of the gas turbine engine such that the sun gear supports the epicyclic gearbox relative to the frame of the gas turbine engine.

[0152] The epicyclic gearbox of any preceding clause, further comprising a first attachment structure coupled to the sun gear and further configured to be coupled to the frame of the gas turbine engine.

[0153] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the first attachment structure and is further configured to be coupled between the first attachment structure and the frame of the gas turbine engine.

[0154] The epicyclic gearbox of any preceding clause, further comprising a first attachment structure coupled to the sun gear and further configured to be coupled to the second rotating component of the gas turbine engine.

[0155] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the first attachment structure and is further configured to be coupled between the first attachment structure and the second rotating component of the gas turbine engine.

[0156] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled between the first attachment structure and the sun gear.

[0157] The epicyclic gearbox of any preceding clause, further comprising a second attachment structure coupled to the ring gear and further configured to be coupled to the second rotating component of the gas turbine engine.

[0158] The epicyclic gearbox of any preceding clause, wherein the isolation damper is coupled to the second attachment structure and is further configured to be coupled between the second attachment structure and the second rotating component of the gas turbine engine.

[0159] The epicyclic gearbox of any preceding clause, wherein the ring gear is configured to be coupled to the frame of the gas turbine engine such that the ring gear supports the epicyclic gearbox relative to the frame of the gas turbine engine.

[0160] The epicyclic gearbox according to any preceding paragraph, further comprising a second attachment structure coupled to the ring gear and further configured to be coupled to the frame of the gas turbine engine.

[0161] The epicyclic gearbox according to any preceding paragraph, wherein the isolation damper is coupled to the second attachment structure and further configured to be coupled between the second attachment structure and the frame of the gas turbine engine.

[0162] The epicyclic gearbox according to any preceding paragraph, further comprising a second attachment structure coupled to the ring gear and further configured to be coupled to the first rotating component of the gas turbine engine.

[0163] The epicyclic gearbox according to any preceding paragraph, wherein the isolation damper is coupled to the second attachment structure and further configured to be coupled between the second attachment structure and the first rotating component of the gas turbine engine.

[0164] The epicyclic gearbox according to any preceding paragraph, wherein the isolation damper is coupled between a second attachment structure and the ring gear.

[0165] The epicyclic gearbox according to any preceding paragraph, wherein the at least one shape memory alloy damper is arranged on an outer surface of the planet carrier such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the plurality of planet gears and the frame of the gas turbine engine.

[0166] The epicyclic gearbox according to any preceding paragraph, wherein the at least one shape memory alloy damper is arranged on an outer surface of the planet carrier such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the plurality of planet carriers and the first rotating component of the gas turbine engine.

[0167] The epicyclic gearbox according to any preceding paragraph, wherein the at least one shape memory alloy damper is arranged on an outer surface of the planet carrier such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the plurality of planet gears and the second rotating component of the gas turbine engine.

[0168] The epicyclic gearbox according to any preceding paragraph, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the planet carrier.

[0169] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the first attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the sun gear and the first rotating component of the gas turbine engine.

[0170] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the first attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the sun gear and the second rotating component of the gas turbine engine.

[0171] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the first attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the sun gear and the frame of the gas turbine engine.

[0172] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the first attachment structure.

[0173] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the second attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the ring gear and the second rotating component of the gas turbine engine.

[0174] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the second attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the ring gear and the first rotating component of the gas turbine engine.

[0175] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is arranged on an outer surface of the second attachment structure such that the at least one shape memory alloy damper is configured to reduce vibrations transmitted between the ring gear and the frame of the gas turbine engine.

[0176] The epicyclic gearbox of any preceding clause, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the second attachment structure.

[0177] The epicyclic gearbox of any preceding clause, wherein the second attachment structure comprises a first segment and a second segment.

[0178] The epicyclic gearbox of any preceding Clause, wherein the at least one shape memory alloy damper is coupled between the first segment and the second segment of the second attachment structure.

[0179] The epicyclic gearbox of any preceding Clause, wherein the first segment is parallel to the second segment such that the second attachment structure defines a U-shape.

[0180] The epicyclic gearbox of any preceding Clause, wherein the first attachment structure comprises a first segment and a second segment.

[0181] The epicyclic gearbox of any preceding Clause, wherein the at least one shape memory alloy damper is coupled between the first segment and the second segment of the first attachment structure.

[0182] The epicyclic gearbox of any preceding Clause, wherein the first segment is parallel to the second segment such that the first attachment structure defines a U-shape.

[0183] The epicyclic gearbox of any preceding Clause, wherein the first rotating component comprises at least one of a turbine or a component of a turbine section.

[0184] The epicyclic gearbox of any preceding Clause, wherein the second rotating component comprises at least one of a fan or a component of a fan assembly.

[0185] The epicyclic gearbox of any preceding Clause, wherein the second rotating component comprises at least one of a high pressure shaft, a high pressure turbine, a high pressure compressor, or a component of a high pressure rotor.

[0186] The epicyclic gearbox of any preceding Clause, wherein the first rotating component comprises at least one of a low pressure shaft, a low pressure turbine, a low pressure compressor, or a component of a low pressure rotor.

[0187] A fluid transfer system for use within a gas turbine engine, the fluid transfer system comprising: at least one fluid conduit comprising a tube configured to transfer at least one of fuel, air, or oil from a first location of the gas turbine engine to a second location of the gas turbine engine; and at least one shape memory alloy damper disposed in association with the at least one fluid conduit, the at least one shape memory alloy damper configured to reduce vibrations acting on the at least one fluid conduit.

[0188] The fluid transfer system of any preceding Clause, wherein the at least one shape memory alloy damper is disposed on an outer surface of the tube of the at least one fluid conduit.

[0189] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the tube.

[0190] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper comprises at least one of a sheet or a tube.

[0191] The fluid transfer system of any preceding clause, further comprising an outer tube surrounding the tube of the at least one fluid conduit, the shape memory alloy damper disposed on the outer surface of the tube.

[0192] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper comprises at least one of a sheet or a tube disposed between the outer surface of the tube and the outer tube.

[0193] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper comprises a plurality of shape memory alloy inserts disposed between the outer surface of the tube and the outer tube.

[0194] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper is cryogenically fitted between the outer surface of the tube and the outer tube.

[0195] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper comprises a shape memory alloy clamp configured to couple the tube of the at least one fluid conduit to a frame of the gas turbine engine.

[0196] The fluid transfer system of any preceding clause, wherein the at least one fluid conduit comprises a first fluid conduit or a first tube segment and a second fluid conduit or a second tube segment.

[0197] The fluid transfer system of any preceding clause, wherein the at least one shape memory alloy damper comprises a bridge coupled between the first fluid conduit or the first tube segment and the second fluid conduit or the second tube segment.

[0198] A gas turbine engine defining an axial direction, the gas turbine engine comprising: a frame; a turbine section comprising a turbine; and a fan assembly comprising a fan.

[0199] The gas turbine engine of any preceding paragraph, wherein the gas turbine engine further comprises a epicyclic gearbox supported by the frame and coupling the turbine of the turbine section to the fan of the fan assembly, the epicyclic gearbox comprising: a sun gear centrally located, the sun gear comprising a plurality of teeth, the sun gear drivingly coupled to the turbine of the turbine section; a plurality of planet gears surrounding the sun gear, each of the plurality of planet gears comprising a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each of the plurality of planet gears; a ring gear surrounding the plurality of planet gears, the ring gear comprising a plurality of teeth configured to mesh with the teeth of each of the planet gears such that the ring gear rotates relative to the plurality of planet gears; and at least one shape memory alloy damper disposed in association with at least one of the sun gear, the ring gear, or the plurality of planet gears such that vibrations transmitted through the epicyclic gearbox to at least one of the frame, the turbine, or the fan of the gas turbine engine are reduced.

[0200] The gas turbine engine of any preceding paragraph, wherein the epicyclic gearbox further comprises: a carrier coupled to each of the plurality of planet gears.

[0201] The gas turbine engine of any preceding paragraph, wherein the carrier is coupled to the frame of the gas turbine engine such that the carrier supports the epicyclic gearbox relative to the frame of the gas turbine engine.

[0202] The gas turbine engine of any preceding paragraph, wherein the ring gear is drivingly coupled to the fan of the fan assembly.

[0203] The gas turbine engine of any preceding paragraph, wherein the carrier is drivingly coupled to the fan of the fan assembly.

[0204] The gas turbine engine of any preceding paragraph, wherein the ring gear is coupled to the frame of the gas turbine engine such that the ring gear supports the epicyclic gearbox relative to the frame of the gas turbine engine.

[0205] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed in association with the carrier such that vibrations transmitted through the epicyclic gearbox are at least partially isolated from the frame of the gas turbine engine.

[0206] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam is disposed in association with the planet carrier such that vibrations transmitted through the epicyclic gear case are at least partially isolated from the fan of the gas turbine engine.

[0207] The gas turbine engine of any preceding paragraph, wherein each of the plurality of planet gears defines a central bore within a central ring, wherein the planet carrier includes a plurality of pinions, each of the plurality of pinions corresponding to a planet gear of the plurality of planet gears, each pinion extending in an axial direction within the central bore of its corresponding planet gear.

[0208] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear case further includes a plurality of bearing assemblies, each of the plurality of bearing assemblies associated with a pinion and planet gear pair, each bearing assembly arranged between the central ring of the corresponding planet gear and an outer surface of the corresponding pinion such that the bearing assembly allows relative rotation of the corresponding planet gear about its corresponding pinion.

[0209] The gas turbine engine of any preceding paragraph, wherein a plurality of the at least one shape memory alloy dam are configured as bearing dampers, each bearing dam arranged between the bearing assembly and the outer surface of the pinion of the associated pinion and planet gear pair.

[0210] The gas turbine engine of any preceding paragraph, wherein each bearing dam is arranged between the bearing assembly and the outer surface of the pinion of the associated pinion and planet gear pair.

[0211] The gas turbine engine of any preceding paragraph, wherein each bearing dam includes a plurality of shape memory alloy members extending radially relative to the central bore between the outer surface of the corresponding pinion and the corresponding bearing assembly of the associated pinion and planet gear pair.

[0212] The gas turbine engine of any preceding paragraph, wherein each bearing dam includes a shape memory alloy ring arranged within a central bore between the outer surface of the pinion and the corresponding bearing assembly of the associated pinion and planet gear pair.

[0213] The gas turbine engine of any preceding paragraph, wherein the plurality of shape memory alloy members includes a first set of shape memory alloy members extending radially relative to the central bore from the outer surface of the corresponding pinion to the shape memory alloy ring.

[0214] The gas turbine engine of any preceding paragraph, wherein the plurality of shape memory alloy members includes a second set of shape memory alloy members extending radially from the shape memory alloy ring relative to the central bore to a corresponding bearing assembly of an associated pinion and planet gear pair.

[0215] The gas turbine engine of any preceding paragraph, wherein the bearing damper includes a plurality of closed shape memory alloy elements.

[0216] The gas turbine engine of any preceding paragraph, wherein each of the plurality of closed shape memory alloy elements is disposed between the outer surface of a corresponding pinion and a corresponding bearing assembly of an associated pinion and planet gear pair within the central bore of the planet gear.

[0217] The gas turbine engine of any preceding paragraph, wherein at least one bearing damper includes a plurality of shape memory alloy plates.

[0218] The gas turbine engine of any preceding paragraph, wherein each bearing damper includes a plurality of shape memory alloy plates.

[0219] The gas turbine engine of any preceding paragraph, wherein each of the plurality of shape memory alloy plates extends circumferentially relative to the central bore of the planet gear and is disposed between the outer surface of a corresponding pinion and a corresponding bearing assembly of an associated pinion and planet gear pair.

[0220] The gas turbine engine of any preceding paragraph, wherein the at least one bearing damper includes a shape memory alloy mesh ring disposed between the outer surface of a corresponding pinion and a corresponding bearing assembly of an associated pinion and planet gear pair.

[0221] The gas turbine engine of any preceding paragraph, wherein each bearing damper includes a shape memory alloy mesh ring disposed between the outer surface of a corresponding pinion and a corresponding bearing assembly of an associated pinion and planet gear pair.

[0222] The gas turbine engine of any preceding paragraph, wherein at least one bearing damper includes a plurality of shape memory alloy coil springs extending radially relative to the central bore between the outer surface of a corresponding pinion and a corresponding bearing assembly of an associated pinion and planet gear pair.

[0223] The gas turbine engine of any preceding paragraph, wherein each bearing damper comprises a plurality of shape memory alloy coil springs extending radially between the outer surface of the corresponding pinion and an associated pinion and planet gear pair with respect to the central bore.

[0224] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear box further comprises: a first attachment structure coupled to the sun gear and coupled between the sun gear and the turbine of the turbine section.

[0225] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled between the first attachment structure and the sun gear.

[0226] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear box further comprises: a second attachment structure coupled to the ring gear and coupled between the ring gear and the fan of the gas turbine engine.

[0227] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled to the second attachment structure and coupled between the second attachment structure and the fan of the gas turbine engine.

[0228] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled between the first attachment structure and the sun gear.

[0229] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear box further comprises: a second attachment structure coupled to the ring gear and coupled between the ring gear and the frame of the gas turbine engine.

[0230] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled to the second attachment structure and coupled between the second attachment structure and the frame of the gas turbine engine.

[0231] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear box further comprises: a second attachment structure coupled to the ring gear and coupled between the ring gear and the frame of the gas turbine engine.

[0232] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled to the second attachment structure and coupled between the second attachment structure and the frame of the gas turbine engine.

[0233] The gas turbine engine of any preceding paragraph, wherein the isolation damper is coupled between the second attachment structure and the ring gear.

[0234] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the planet carrier such that the at least one shape memory alloy damper reduces vibrations transmitted between the planet carrier and the frame of the gas turbine engine.

[0235] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the planet carrier such that the at least one shape memory alloy damper reduces vibrations transmitted between the plurality of planet carriers and the fan of the gas turbine engine.

[0236] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the planet carrier.

[0237] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the first attachment structure such that the at least one shape memory alloy damper reduces vibrations transmitted between the sun gear and the turbine of the gas turbine engine.

[0238] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the first attachment structure.

[0239] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the second attachment structure such that the at least one shape memory alloy damper reduces vibrations transmitted between the ring gear and the fan of the gas turbine engine.

[0240] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the second attachment structure such that the at least one shape memory alloy damper reduces vibrations transmitted between the ring gear and the frame of the gas turbine engine.

[0241] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is cryogenically fitted to the outer surface of the second attachment structure.

[0242] The gas turbine engine of any preceding paragraph, wherein the second attachment structure comprises a first segment and a second segment.

[0243] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is coupled between the first segment and the second segment of the second attachment structure.

[0244] The gas turbine engine of any preceding paragraph, wherein the first segment is parallel to the second segment such that the second attachment structure defines a U-shape.

[0245] The gas turbine engine of any preceding paragraph, wherein the first attachment structure comprises a first segment and a second segment.

[0246] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is coupled between the first segment and the second segment of the first attachment structure.

[0247] The gas turbine engine of any preceding paragraph, wherein the first segment is parallel to the second segment such that the first attachment structure defines a U-shape.

[0248] The gas turbine engine of any preceding paragraph, wherein the gas turbine engine further comprises a fluid transfer system comprising: at least one fluid conduit comprising a tube configured to transfer at least one of fuel, air, or oil from a first location of the gas turbine engine to a second location of the gas turbine engine; and at least one shape memory alloy damper disposed in association with the at least one fluid conduit, the at least one shape memory alloy damper configured to reduce vibrations acting on the at least one fluid conduit.

[0249] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is disposed on an outer surface of the tube of the at least one fluid conduit.

[0250] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper is cryogenically fitted onto the outer surface of the tube.

[0251] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy damper comprises at least one of a sheet or a tube.

[0252] The gas turbine engine of any preceding paragraph, wherein the fluid transfer system further comprises: an outer tube surrounding the tube of the at least one fluid conduit, the shape memory alloy damper disposed on the outer surface of the tube.

[0253] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam comprises at least one of a sheet or a tube disposed between the outer surface of the tube and the outer tube.

[0254] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam comprises a plurality of shape memory alloy inserts disposed between the outer surface of the tube and the outer tube.

[0255] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam is low temperature adapted between the outer surface of the tube and the outer tube.

[0256] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam comprises a shape memory alloy clamp coupled between the tube of the at least one fluid conduit and the frame of the gas turbine engine.

[0257] The gas turbine engine of any preceding paragraph, wherein the at least one fluid conduit comprises a first fluid conduit or a first tube segment and a second fluid conduit or a second tube segment.

[0258] The gas turbine engine of any preceding paragraph, wherein the at least one shape memory alloy dam comprises a bridge coupled between the first fluid conduit or the first tube segment and the second fluid conduit or the second tube segment.

[0259] A gas turbine engine defining an axial direction, the gas turbine engine comprising: a frame; a first rotating component; a second rotating component; an epicyclic gearbox supported by the frame and coupling the first rotating component to the second rotating component, the epicyclic gearbox comprising: a sun gear centrally located, the sun gear comprising a plurality of teeth, the sun gear drivingly coupled to the first rotating component; a plurality of planet gears surrounding the sun gear, each of the planet gears comprising a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each of the plurality of planet gears; a ring gear surrounding the plurality of planet gears, the ring gear comprising a plurality of teeth configured to mesh with the teeth of each of the planet gears such that the ring gear rotates relative to the plurality of planet gears; at least one shape memory alloy damper disposed in association with at least one of the sun gear, the ring gear, or the plurality of planet gears such that vibrations transmitted through the epicyclic gearbox to at least one of the frame, the first rotating component, or the second rotating component of the gas turbine engine are reduced; and at least one clutch drivingly coupled between the epicyclic gearbox and at least one of the first rotating component or the second rotating component.

[0260] The gas turbine engine according to the preceding clause, wherein the first rotating component comprises at least one of a turbine or a component of a turbine section.

[0261] The gas turbine engine according to any preceding clause, wherein the second rotating component comprises at least one of a fan or a component of a fan assembly.

[0262] The gas turbine engine according to the preceding clause, wherein the second rotating component comprises at least one of a turbine or a component of a turbine section.

[0263] The gas turbine engine according to any preceding clause, wherein the first rotating component comprises at least one of a fan or a component of a fan assembly.

[0264] The gas turbine engine according to any preceding clause, wherein the second rotating component comprises at least one of a high pressure shaft, a high pressure turbine, a high pressure compressor, or a component of a high pressure rotor.

[0265] The gas turbine engine according to any preceding clause, wherein the first rotating component comprises at least one of a low pressure shaft, a low pressure turbine, a low pressure compressor, or a component of a low pressure rotor.

[0266] The gas turbine engine of any preceding paragraph, wherein the first rotating component comprises at least one of a high pressure shaft, a high pressure turbine, a high pressure compressor, or a high pressure rotor.

[0267] The gas turbine engine of any preceding paragraph, wherein the second rotating component comprises at least one of a low pressure shaft, a low pressure turbine, a low pressure compressor, or a low pressure rotor.

[0268] The gas turbine engine of any preceding paragraph, wherein the ring gear is drivingly coupled to the second rotating component.

[0269] The gas turbine engine of any preceding paragraph, further comprising: a planet carrier coupled between each of the plurality of planet gears and the frame of the gas turbine engine, such that the planet carrier supports the epicyclic gear box relative to the frame of the gas turbine engine.

[0270] The gas turbine engine of any preceding paragraph, further comprising: a planet carrier coupled between each of the plurality of planet gears and the second rotating component of the gas turbine engine.

[0271] The gas turbine engine of any preceding paragraph, wherein the epicyclic gear box is configured as a power gear box.

[0272] The gas turbine engine of any preceding paragraph, further comprising a clutch coupled between at least a portion of the first rotating component and the epicyclic gear box.

[0273] The gas turbine engine of any preceding paragraph, further comprising a clutch coupled between at least a portion of the second rotating component and the epicyclic gear box.

[0274] The gas turbine engine of any preceding paragraph, further comprising an accessory gear box drivingly coupled to the first rotating component.

[0275] The gas turbine engine of any preceding paragraph, wherein the accessory gear box comprises a sun gear, a ring gear, a plurality of planet gears, and at least one shape memory alloy damper disposed in association with at least one of the sun gear, the ring gear, or the plurality of planet gears of the accessory gear box and configured to reduce vibrations transmitted through the accessory gear box.

[0276] The gas turbine engine of any preceding paragraph, further comprising an electric machine, the accessory gear box drivingly coupled between the first rotating component and the electric machine.

[0277] The gas turbine engine of any preceding paragraph, wherein the accessory gear box is drivingly coupled to the first rotating component at a connection point, and wherein the clutch is positioned between the connection point and the epicyclic gear box.

[0278] The gas turbine engine of any preceding paragraph, wherein the gas turbine engine further comprises a third rotating component and an inter-spool clutch coupled between the first rotating component and the third rotating component.

[0279] The gas turbine engine of any preceding paragraph, wherein the inter-spool clutch is positioned along the first rotating component opposite the clutch relative to the connection point associated with the accessory gear box.

[0280] The gas turbine engine of any preceding paragraph, wherein the third rotating component comprises at least one of a high pressure shaft, a high pressure turbine, a high pressure compressor, or a high pressure rotor.

Claims

1. A epicyclic gearbox configured to be supported by a frame of a gas turbine engine and configured to transmit rotational motion between a first rotating component of the gas turbine engine and a second rotating component of the gas turbine engine, characterized in that, The gearbox comprises: a sun gear located at a center, the sun gear comprising a plurality of teeth, the sun gear configured to be drivingly coupled to the first rotating component of the gas turbine engine; a plurality of planet gears surrounding the sun gear, each of the planet gears comprising a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each of the plurality of planet gears, the plurality of planet gears comprising a central bore; a ring gear surrounding the plurality of planet gears, the ring gear comprising a plurality of teeth configured to mesh with the teeth of each of the planet gears such that the ring gear rotates relative to the plurality of planet gears; a planet carrier, wherein each of the plurality of planet gears is rotatably attached to the planet carrier; a countershaft having an outer surface extending at least partially through the central bore of the plurality of planet gears; a bearing assembly having an inner race drivingly coupled to the plurality of planet gears, wherein the inner race circumferentially surrounds at least a portion of the outer surface of the countershaft; and at least one shape memory alloy dam disposed between an outer surface of the countershaft and the inner race of the bearing assembly, wherein the at least one shape memory alloy dam is configured to reduce vibrations transmitted through the epicyclic gearbox to at least one of the frame, the first rotating component, or the second rotating component of the gas turbine engine.

2. The epicyclic gearbox of claim 1, wherein, wherein the at least one shape memory alloy dam comprises a plurality of shape memory alloy members extending radially between the outer surface of the countershaft and the inner race of the bearing assembly relative to the central bore.

3. The epicyclic gearbox of claim 2, wherein, wherein each bearing dam comprises a shape memory alloy ring disposed within the central bore between the outer surface of the countershaft and the inner race of the bearing, and wherein the plurality of shape memory alloy members comprises a first set of shape memory alloy members extending radially from the outer surface of the countershaft to the shape memory alloy ring relative to the central bore of the plurality of planet gears and a second set of shape memory alloy members extending radially from the shape memory alloy ring to the inner race of the bearing assembly relative to the central bore.

4. The epicyclic gearbox of claim 1, wherein, wherein the shape memory alloy dam comprises a plurality of closed shape memory alloy elements disposed between the outer surface of the countershaft and the inner race of the bearing assembly within the central bore of the plurality of planet gears.

5. The epicyclic gearbox of claim 1, wherein, wherein the at least one shape memory alloy dam comprises a plurality of shape memory alloy plates, each shape memory alloy plate extending circumferentially relative to the central bore of the planet gears and disposed between the outer surface of the countershaft and the inner race of the bearing assembly.

6. The epicyclic gearbox of claim 1, wherein, wherein the at least one shape memory alloy damper includes a shape memory alloy mesh ring disposed between the outer surface of the countershaft and the inner race of the bearing assembly.

7. The epicyclic gearbox of claim 1, wherein, wherein the at least one shape memory alloy damper includes a plurality of shape memory alloy coil springs extending radially between the outer surface of the countershaft and the inner race of the bearing assembly relative to the central bore.

8. The epicyclic gearbox of claim 1, wherein, wherein the at least one shape memory alloy damper includes a second shape memory alloy damper configured to couple to an isolated damper of the planetary gear carrier and further configured to couple between the planetary gear carrier and the frame of the gas turbine engine.

9. The epicyclic gearbox of claim 1, wherein: wherein the at least one shape memory alloy damper includes a second shape memory alloy damper disposed on an outer surface of the planetary gear carrier such that the second shape memory alloy damper is configured to reduce vibrations transmitted between the plurality of planetary gears and the frame of the gas turbine engine.

10. The epicyclic gearbox of claim 9, wherein, wherein the second shape memory alloy damper is low temperature adapted to the outer surface of the planetary gear carrier.

11. The epicyclic gearbox of claim 1, wherein, further comprising: an attachment structure coupled to the ring gear and further configured to couple to the second rotating component of the gas turbine engine, the attachment structure including a first segment and a second segment, wherein the at least one shape memory alloy damper includes a second shape memory alloy damper coupled between the first segment and the second segment of the attachment structure.

12. The epicyclic gearbox of claim 11, wherein, wherein the first segment is parallel to the second segment such that the attachment structure defines a U-shape.

13. A gas turbine engine defining an axial direction, characterized by, the gas turbine engine includes: a frame; a turbine section including a turbine; a fan assembly including a fan; and an epicyclic gearbox supported by the frame and drivingly coupling the turbine of the turbine section to the fan of the fan assembly, the epicyclic gearbox including: a sun gear located at a center, the sun gear including a plurality of teeth, the sun gear drivingly coupled to the turbine of the turbine section; a plurality of planetary gears surrounding the sun gear, each of the planetary gears including a plurality of teeth configured to mesh with the teeth of the sun gear such that rotation of the sun gear causes rotation of each of the plurality of planetary gears, the plurality of planetary gears including a central bore; a ring gear surrounding the plurality of planetary gears, the ring gear including a plurality of teeth configured to mesh with the teeth of each of the planetary gears such that the ring gear rotates relative to the plurality of planetary gears; a planetary gear carrier, wherein each of the plurality of planetary gears is rotatably attached to the planetary gear carrier; and a plurality of shape memory alloy dampers coupled between the central bore of the plurality of planetary gears and the frame of the gas turbine engine. a countershaft having an outer surface extending at least partially through the central bore of the plurality of planetary gears, wherein the countershaft is coupled to the frame; a bearing assembly having an inner race drivably coupled to the plurality of planetary gears, wherein the inner race circumferentially surrounds at least a portion of the outer surface of the countershaft; and at least one shape memory alloy damper disposed between an outer surface of the countershaft and the inner race of the bearing assembly such that vibrations transmitted through the epicyclic gearbox to at least one of the frame, the turbine, or the fan of the gas turbine engine are reduced.

14. The gas turbine engine of claim 13, wherein, wherein the at least one shape memory alloy damper includes a second shape memory alloy damper configured as an isolation damper coupled between the planetary carrier and the frame of the gas turbine engine.

15. The gas turbine engine of claim 13, wherein, wherein the at least one shape memory alloy damper includes a second shape memory alloy damper disposed on an outer surface of the planetary carrier such that the second shape memory alloy damper reduces vibrations transmitted between the planetary carrier and the frame of the gas turbine engine.

16. The gas turbine engine of claim 13, wherein, further comprising: an attachment structure coupled between the ring gear and the fan of the fan assembly, the attachment structure including a first segment and a second segment, wherein the at least one shape memory alloy damper includes a second shape memory alloy damper coupled between the first segment and the second segment of the attachment structure.

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