Blade including integrated damping structure and method of forming the same

Abstract

Disclosed herein are vanes including integrated damping structures. A airfoil disposed within a flowpath of a gas turbine engine, the gas turbine engine defining an axial axis, a radial axis, and a circumferential axis, includes an airfoil body including a first face, a second face, and a recess formed in the second face; and an airfoil cap having a first surface, the airfoil cap disposed within the recess, the first surface substantially flush with the second face.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to gas turbines, and more particularly, to a blade including an integrated damping structure and a method of forming the same. BACKGROUND

[0002] Gas turbine engines generally include, in serial flow order, an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air enters the inlet section and flows to the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section, thereby creating combustion gases. The combustion gases flow from the combustion section through a hot gas path defined within the turbine section, and then exit the turbine section via the exhaust section. The gas turbine engine produces thrust that propels a vehicle, such as a passenger aircraft, forward. The thrust from the engine is transferred to a wing mount, such as a pylon, and, in turn, the vehicle exerts an equal and opposite reaction force on the wing through the mount. BRIEF DESCRIPTION OF DRAWINGS

[0003] A complete and enabling disclosure of the application, including the best mode thereof, to one of ordinary skill in the art, is set forth in the specification, which is to be taken in conjunction with the appended drawings, wherein:

[0004] FIG. 1 is a cross-sectional view of a prior art gas turbine engine;

[0005] Figure 2 A front view of a fan blade implemented in accordance with the teachings of the present disclosure is shown;

[0006] Figure 3 A first example cross-sectional structure of a fan blade similar to Figure 2 is shown;

[0007] Figure 4 A second example cross-sectional structure of a fan blade similar to Figure 2 is shown;

[0008] Figure 5 A unit structure that can be used with the fan blade of Figure 2 is shown; and

[0009] Figure 6 is a flowchart illustrating the operation of a method for manufacturing the fan blade of Figure 2 and Figure 4 is shown.

[0010] The drawings are not to scale. Instead, the dimensions of the layers or regions can be exaggerated in the drawings relative to each other for the sake of explanation. Generally, the same reference numbers in the drawings indicate the same or similar elements or parts throughout the several drawings and the accompanying written description. As used in this patent, a statement that any portion (e.g., layer, film, region, area, or plate) is on (e.g., positioned on, located on, disposed on, or formed on) another portion indicates that the portion is in contact with the other portion, or that the portion is above the other portion with one or more intervening portions therebetween. Connection references (e.g., attached, coupled, connected, joined, separated, disconnected, disconnected, separated, etc.) should be construed broadly and can include intermediate members between the elements, as well as relative movement between elements, unless otherwise stated. As used herein, the term “disconnectably coupled” refers to the ability of two portions to be attached, connected, and / or otherwise joined and then separated, disconnected, and / or otherwise non-destructively separated from each other (e.g., by removing one or more fasteners, removing a connecting portion, etc.). Thus, the connection / disconnection references do not necessarily mean that two elements are directly connected and in a fixed relationship with each other. A statement that any portion is “in contact” with another portion means that there are no intervening portions between the two portions.

[0011] In identifying multiple elements or components that can be individually referenced, the descriptors “first,” “second,” “third,” etc. are used herein. Unless otherwise specified or understood from its usage context, such descriptors are not intended to impart any meaning of priority, physical order, or arrangement in a list, or temporal ordering, but are merely used as labels to refer to multiple elements or components, respectively, for ease of understanding the disclosed examples. In some examples, the descriptor “first” can be used to refer to an element in the detailed description, while a different descriptor (e.g., “second” or “third”) can be used in the claims to refer to the same element. In such instances, it will be understood that such descriptors are used merely for ease of referring to multiple elements or components. DETAILED DESCRIPTION

[0012] Operation of gas turbine engines can result in fan blades, airfoils, and / or wheel blades vibrating, fluttering, and otherwise undesirably moving. In some examples, unmitigated vibrations can result in damage to the fan and / or fan blades. The examples disclosed herein use internal features that slide / friction during airfoil operation to overcome the aforementioned deficiencies. In some examples disclosed herein, fan blades include a two-part cap and body configuration that facilitates use of the sliding / friction features. In examples disclosed herein, fan blades include internal features that provide frictional damping (e.g., coulomb damping, etc.) to the fan blades through internal sandwich joints and / or slip joints. The example fan blades disclosed herein include internal features that mitigate weight and improve vibration response of these fan blades as compared to existing fan blades.

[0013] The terms“upstream” and“downstream” refer to the relative direction with respect to the fluid flow in a fluid path. For example,“upstream” refers to the direction from which the fluid flows, and“downstream” refers to the direction to which the fluid flows.

[0014] Various terms are used herein to describe the orientation of features. As used herein, the orientation of features, forces, and moments are described with reference to the yaw, pitch, and roll axes of the vehicle with which the features, forces, and moments are associated. Generally, the figures are annotated with reference to the axial, radial, and circumferential directions of the gas turbine with which the features, forces, and moments are associated. Generally, the figures are annotated with a set of axes including an axial axis A, a radial axis R, and a circumferential axis C. As used herein, the terms“longitudinal” and“axial” are used interchangeably to refer to a direction parallel to the axial axis. As used herein, the term“radial” is used to refer to a direction parallel to the radial axis. As used herein, the term“circumferential” is used to refer to a direction parallel to the circumferential axis.

[0015] In some examples used herein, the term“substantially” is used to describe a relationship between two portions in which the relationship is within three degrees of the stated relationship (e.g., a substantially collinear relationship is within three degrees of collinear, a substantially perpendicular relationship is within three degrees of perpendicular, a substantially parallel relationship is within three degrees of parallel, etc.). As used herein, two or more surfaces are“substantially flush” or“substantially level” when the surface profiles are within a 5% tolerance range. As used herein, the term“linkage” refers to a connection between two components that restricts the relative movement of the two components (e.g., restricts at least one degree of freedom of the components, etc.). “Comprise” and“comprising” (and all forms of these terms) are used herein as open-ended terms. Thus, whenever a claim employs the phrase“comprising” or“comprises” (and all forms of these terms) as an opening or in any other transitional phrase, it is understood that additional elements, terms, etc. can be present in addition to those elements that are recited in the corresponding claim or statement. As used herein, the phrase“at least” is used as an open-ended term in, for example, the preamble of a claim, in the same manner as the terms“comprising” and“including” are open-ended. The term“and / or” when used in, for example, the form“A, B, and / or C” is intended to mean that any of the following are possible: (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, and (7) A with B and with C. As used herein in the context of describing structures, components, items, objects, and / or things, the phrase“at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) any of A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects, and / or things, the phrase“at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. As used herein in the context of describing performance or execution of processes, instructions, actions, activities, and / or steps, the phrase“at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing performance or execution of processes, instructions, actions, activities, and / or steps, the phrase“at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.

[0016] As used herein, singular references (e.g., “a,” “an,” “one,” “the,” etc.) do not exclude the plural. As used herein, the term “a” or “an” entity refers to one or more than one of that entity. The terms “a” (or “an”), “one or more” and “at least one” are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions can be implemented by, e.g., a single unit or processor. Additionally, although individual features can be included in different examples or claims, these can possibly be combined, and the inclusion of such features in different examples or claims does not imply that a combination of features is not feasible and / or advantageous.

[0017] Reference is now made to the drawings, wherein like numerals refer to like elements throughout. FIG. 1 is a schematic cross-sectional view of a prior art turbofan gas turbine engine 100 (“turbofan 100”). As shown in FIG. 1, the turbofan 100 defines a longitudinal or axial centerline axis 102 extending therethrough for reference. Generally, the turbofan 100 can include a core turbine 104 or gas turbine engine disposed downstream of a fan section 106.

[0018] The core turbine 104 generally includes a substantially tubular outer casing 108 (“turbine casing 108”) defining an annular inlet 110. The outer casing 108 can be formed of a single casing or multiple casings. The outer casing 108 encloses, in serial flow relationship, a compressor section having a booster or low pressure compressor 112 (“LP compressor 112”) and a high pressure compressor 114 (“HP compressor 114”), a combustion section 116, a turbine section having a high pressure turbine 118 (“HP turbine 118”) and a low pressure turbine 120 (“LP turbine 120”), and an exhaust section 122. A high pressure shaft or spool 124 (“HP shaft 124”) drives coupling the HP turbine 118 and the HP compressor 114. A low pressure shaft or spool 126 (“LP shaft 126”) drives coupling the LP turbine 120 and the LP compressor 112. The LP shaft 126 can also be coupled to a fan shaft or spool 128 (“fan shaft 128”) of the fan section 106. In some examples, the LP shaft 126 can be directly coupled to the fan shaft 128 (i.e., a direct drive configuration). In alternative configurations, the LP shaft 126 can be coupled to the fan shaft 128 via a reduction gear box 130 (e.g., an indirect drive or geared drive configuration).

[0019] As shown in FIG. 1, the fan section 106 includes a plurality of fan blades 132 coupled to and extending radially outward from a fan shaft 128. An annular fan casing or nacelle 134 circumferentially surrounds at least a portion of the fan section 106 and / or the core turbine 104. The nacelle 134 is supported relative to the core turbine 104 by a plurality of circumferentially spaced outlet guide vanes 136. Further, a downstream section 138 of the nacelle 134 can surround an outer portion of the core turbine 104 to define a bypass airflow passage 140 therebetween.

[0020] As shown in FIG. 1, air 142 enters an inlet portion 144 of the turbofan 100 during operation of the turbofan 100. A first portion 146 of the air 142 flows into the bypass airflow passage 140, while a second portion 148 of the air 142 flows into the inlet 110 of the LP compressor 112. One or more successive stages of LP compressor stator vanes 150 and LP compressor rotor blades 152 coupled to the LP shaft 126 progressively compress the second portion 148 of the air 142 flowing through the LP compressor 112 and are directed to the HP compressor 114. Next, one or more successive stages of HP compressor stator vanes 154 and HP compressor rotor blades 156 coupled to the HP shaft 124 further compress the second portion 148 of the air 142 flowing through the HP compressor 114. This provides compressed air 158 to the combustion section 116, where it is mixed with fuel and combusted to provide combustion gases 160.

[0021] The combustion gases 160 flow through the HP turbine 118, where one or more successive stages of HP turbine stator vanes 162 and HP turbine rotor blades 164 coupled to the HP shaft 124 extract a first portion of kinetic and / or thermal energy from the combustion gases 160. This energy extraction supports operation of the HP compressor 114. The combustion gases 160 then flow through the LP turbine 120, where one or more successive stages of LP turbine stator vanes 166 and LP turbine rotor blades 168 coupled to the LP shaft 126 extract a second portion of thermal and / or kinetic energy therefrom. This energy extraction causes the LP shaft 126 to rotate, thereby supporting operation of the LP compressor 112 and / or rotation of the fan shaft 128. The combustion gases 160 then exit the core turbine 104 through its exhaust section 122.

[0022] With the turbofan 100, the core turbine 104 has similar purposes and sees similar environments in land-based gas turbines, turbojet engines in which the ratio of the first portion 146 of air 142 to the second portion 148 of air 142 is less than the ratio of the turbofan, and ductless fan engines in which the fan section 106 is without the nacelle 134. In each turbofan, turbojet, and ductless engine, a reduction device (e.g., the reduction gear box 130) can be included between any shaft and spool. For example, the reduction gear box 130 can be disposed between the LP shaft 126 and the fan shaft 128 of the fan section 106. FIG. 1 also includes a cowling 170 and biasing gimbal joints 172, 174, 176. The cowling 170 is a covering that can reduce drag and cool the engine. The biasing gimbal joints 172, 174, 176 can, for example, include infrared cameras to detect thermal anomalies in the area under the cowling of the turbofan 100.

[0023] Figure 2 A front view of a fan blade 200 implemented in accordance with the teachings of the present disclosure is shown. The fan blade 200 can be used in conjunction with the fan blades 132 of FIG. 1. In the illustrated example, the fan blade 200 has a span 202, a chord 204, a tip 206, and a root 208. In the illustrated example, the fan blade 200 has a leading edge 210, a trailing edge 211, a first face 212, and a second face 214. In the illustrated example, the fan blade 200 includes an airfoil body 216 and a cap 218. The airfoil body 216 has the first face 212, and the cap 218 has the second face 224. While the examples disclosed herein are described with reference to the fan blade 200, in other examples, the teachings of the present disclosure can be implemented on any airfoil. Figure 2 Figure 2 Figure 2

[0024] The fan blade 200 extends from the root 208 to the tip 206, which defines the span 202. The fan blade 200 can be composed of any suitable material (e.g., titanium, aluminum, steel, nickel alloy, copper alloy, iron alloy, another metal, reinforced plastic, fiberglass, metal composite, carbon polymer, glass polymer, another polymer, etc.) or combination thereof. In some examples, the airfoil body 216 and the cap 218 are composed of the same material. In other examples, the airfoil body 216 and the cap 218 can be composed of different materials. The fan blade 200 can have any suitable shape, size, and / or thickness. The fan blade 200 can be manufactured by additive manufacturing, machining, and / or any other suitable manufacturing method. An example method of manufacturing the fan blade 200 is described below in connection with FIG. 2. Figure 6

[0025] In the illustrated example, the fan blade 200 has a span 202, a chord 204, a tip 206, and a root 208. In the illustrated example, the fan blade 200 has a leading edge 210, a trailing edge 211, a first face 212, and a second face 214. In the illustrated example, the fan blade 200 includes an airfoil body 216 and a cap 218. The airfoil body 216 has the first face 212, and the cap 218 has the second face 224. While the examples disclosed herein are described with reference to the fan blade 200, in other examples, the teachings of the present disclosure can be implemented on any airfoil. Figure 2 ​​​​In the middle, the cap 218 is disposed in the recessed portion 222 (e.g., groove, recess, chamber, planer, hole, recess, slot, etc.) of the airfoil body 216. Figure 2 In the example shown, the surface 220 of the airfoil body 216 and the surface 224 of the cap 218 are flush (e.g., flat, horizontal, etc.) and form the first surface 212 of the airfoil. Figure 2 In this example, the corresponding openings in surface 224 and recessed portion 222 have shapes similar to surface 212. In other examples, the corresponding openings in surface 224 and recessed portion 222 may have any other suitable shapes.

[0026] exist Figure 2 In this configuration, the airfoil body 216 and the cap 218 form multiple interfaces. These interfaces allow portions of the airfoil body 216 to slide against portions of the cap 218 in a manner that suppresses the vibrational response of the fan blade 200 via frictional damping (e.g., friction, slippage, etc.). In other words, the frictional damping provided by the interfaces between the airfoil body 216 and the cap 218 causes excess energy from the vibrations of the fan blade 200 to dissipate. In some examples, the multiple interfaces between the airfoil body 216 and the cap 218 can be configured to prevent critical vibration modes of the fan blade 200. Example configurations of the airfoil body 216 and the cap 218 are described below. Figure 3 and Figure 4 Describe it.

[0027] Figure 3 It shows Figure 2 The first example cross-sectional structure 300 of the fan blade 200. In Figure 3 In the example shown, the cross-sectional structure 300 is formed by the airfoil body 216 and the cap 218. Figure 3 In the example shown, the cap 218 is disposed on the lip 302 of the airfoil body 216. Figure 3 In the example shown, the cross-sectional structure 300 includes a first cavity 306A, a second cavity 306B, a third cavity 306C, a fourth cavity 306D, a fifth cavity 306E, a sixth cavity 306F, and a seventh cavity 306G, etc. Figure 3 In the example shown, the cap 218 includes a first cap rib 308A, a second cap rib 308B, a third cap rib 308C, a fourth cap rib 308D, a fifth cap rib 308E, and a sixth cap rib 308F. Figure 3 In the example shown, the airfoil body 216 includes a first body rib 310A, a second body rib 310B, a third body rib 310C, a fourth body rib 310D, a fifth body rib 310E, and a sixth body rib 310F. Figure 3In the example shown, the first cap rib 308A and the first main body rib 310A form a first interface 312A, the second cap rib 308B and the second main body rib 310B form a second interface 312B, the third cap rib 308C and the third main body rib 310C form a third interface 312C, the fourth cap rib 308D and the fourth main body rib 310D form a fourth interface 312D, the fifth cap rib 308E and the fifth main body rib 310E form a fifth interface 312E, and the sixth cap rib 308F and the sixth main body rib 310F form a sixth interface 312F. Although Figure 3 The example shown includes seven cavities and associated ribs, but other examples implemented in accordance with the teachings of this disclosure may include any suitable number of cavities and ribs.

[0028] In some examples, the cap 218 and the wing-shaped body 216 can be joined together by adhesives, welding, press-fit locking mechanisms, shrink-fit locking mechanisms, etc. For example, adhesive can be applied to the lip 302 to bond the cap 218 when it is positioned in the recess 222. Figure 3 In the illustrated example, the connection between the cap 218 and the airfoil body 216 forms a first surface 212, such that the first surface 212 is substantially horizontal (e.g., substantially flush) and continuous. In some examples, the contact between the cap 218 and the airfoil body 216 (e.g., at the lip 302, interfaces 312A, 312B, 312C, 312D, 312E, 312F, etc.) may include a wear-resistant coating (e.g., a cobalt-molybdenum-chromium coating, a polytetrafluoroethylene coating, etc.).

[0029] exist Figure 3 In the example shown, cavities 306A, 306B, 306C, 306D, 306E, 306F, and 306G are internal structures of the fan blade 200. Compared to an airfoil of the same size and shape without cavities, cavities 306A, 306B, 306C, 306D, 306E, 306F, and 306G reduce the overall weight of the fan blade 200. Figure 3In the illustrated example of FIG. 3, the cavities 306A, 306B, 306C, 306D, 306E, 306F, 306G are not uniform in size and shape. In other examples, the cavities 306A, 306B, 306C, 306D, 306E, 306F, 306G can be uniform in size and shape. In some examples, the cavities 306A, 306B, 306C, 306D, 306E, 306F, 306G, the ribs 308A, 308B, 308C, 308D, 308E, 308F, 310A, 310B, 310C, 310D, 310E, 310F, and / or the interfaces 312A, 312B, 312C, 312D, 312E, 312F can be shaped to reduce the likelihood of the fan blade 200 vibrating in a critical vibration mode.

[0030] The ribs 308A, 308B, 308C, 308D, 308E, 308F are features (e.g., bosses, protrusions, etc.) of the cap 218 that are capable of forming the interfaces 312A, 312B, 312C, 312D, 312E, 312F. The ribs 310A, 310B, 310C, 310D, 310E, 310F are features (e.g., bosses, protrusions, etc.) of the airfoil body 216 that are capable of forming the interfaces 312A, 312B, 312C, 312D, 312E, 312F. In the illustrated example of FIG. 3, the ribs 308A, 308B, 308C, 308D, 308E, 308F are formed by the cap 218 abutting the airfoil body 216, and are butt joints. Figure 3 In the illustrated example of FIG. 3, the interfaces 312A, 312B, 312C, 312D, 312E, 312F are formed by the ribs of the cap 218 abutting the airfoil body 216, and are butt joints. In other examples, the interfaces 312A, 312B, 312C, 312D, 312E, 312F can be formed by other features of the cap 218 and the airfoil body 216 abutting each other, and can be other types of joints. Figure 4 In the illustrated example of FIG. 3, the interfaces 312A, 312B, 312C, 312D, 312E, 312F are oriented in a plane that is substantially parallel to the first face 212. During operation of the fan blade 200, the interfaces 312A, 312B, 312C, 312D, 312E, 312F cause the cap 218 and the airfoil body 216 to slide and / or rub, which frictionally dampens the fan blade 200. In particular, vibration energy of the fan blade 200 is dissipated (e.g., as heat, etc.) by the friction and / or sliding of the interfaces 312A, 312B, 312C, 312D, 312E, 312F.

[0031] Figure 4 A second example cross-sectional structure 401 of a fan blade 400 is shown. In the illustrated example of FIG. 4, the cross-sectional structure 401 is formed by an airfoil body 402 and a cap 404. In the illustrated example of FIG. 4, the cap 404 is disposed on the lip 302 of the airfoil body 402. In the illustrated example of FIG. 4, the cap 404 is disposed on the lip 302 of the airfoil body 402. Figure 4 In the illustrated example of FIG. 4, the interfaces 412A, 412B, 412C, 412D, 412E, 412F are formed by the ribs of the cap 404 abutting the airfoil body 402, and are butt joints. In other examples, the interfaces 412A, 412B, 412C, 412D, 412E, 412F can be formed by other features of the cap 404 and the airfoil body 402 abutting each other, and can be other types of joints. Figure 4 In the illustrated example of FIG. 4, the interfaces 412A, 412B, 412C, 412D, 412E, 412F are oriented in a plane that is substantially parallel to the first face 212. During operation of the fan blade 400, the interfaces 412A, 412B, 412C, 412D, 412E, 412F cause the cap 404 and the airfoil body 402 to slide and / or rub, which frictionally dampens the fan blade 400. In particular, vibration energy of the fan blade 400 is dissipated (e.g., as heat, etc.) by the friction and / or sliding of the interfaces 412A, 412B, 412C, 412D, 412E, 412F. Figure 4In the example shown, the cross-sectional structure 401 includes a first cavity 404A, a second cavity 404B, a third cavity 404C, a fourth cavity 404D, a fifth cavity 404E, a sixth cavity 404F, and a seventh cavity 404G. Figure 4 In the example shown, the cap 404 includes a first cap rib 406A, a second cap rib 406B, a third cap rib 406C, a fourth cap rib 406D, a fifth cap rib 406E, and a sixth cap rib 406F. Figures 2-3 In the example shown, the airfoil body 402 includes a first main body rib 408A, a second main body rib 408B, a third main body rib 408C, a fourth main body rib 408D, a fifth main body rib 408E, and a sixth main body rib 408F. In the example shown, the first cap rib 406A forms a first interface 410A with the first main body rib 408A, the second cap rib 406B forms a second interface 410B with the second main body rib 408B, the third cap rib 406C forms a third interface 410C with the third main body rib 408C, the fourth cap rib 406D forms a fourth interface 410D with the fourth main body rib 408D, the fifth cap rib 406E forms a fifth interface 410E with the fifth main body rib 408E, and the sixth cap rib 406F forms a sixth interface 410F with the sixth main body rib 408F. The fan blade 400, the airfoil body 402, and the cap 404 have... Figures 2-3 200 fan blades Figures 2-3 Airfoil body 216 and Figure 4 The cap 218 has the same characteristics and functions, unless otherwise stated. Although Figure 3 The example shown includes seven cavities and associated ribs, but other examples implemented in accordance with the teachings of this disclosure may include any suitable number of cavities and ribs.

[0032] In some examples, the cap 404 and the wing-shaped body 402 can be joined together by adhesives, welding, press-fit locking mechanisms, shrink-fit locking mechanisms, etc. For example, adhesive can be applied to the lip 302 to bond the cap 404 when it is positioned in the recess 222. Figure 4 In the illustrated example, the connection between the cap 404 and the airfoil body 402 forms a first surface 212, such that the first surface 212 is substantially horizontal (e.g., substantially flush) and continuous. In some examples, the contact between the cap 404 and the airfoil body 402 (e.g., at the lip 302, interfaces 410A, 410B, 410C, 410D, 410E, 410F, etc.) may include a wear-resistant coating (e.g., a cobalt-molybdenum-chromium coating, a polytetrafluoroethylene coating, etc.).

[0033] exist Figure 4In the illustrated example of FIG. 4, cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G are internal structures in fan blade 400 formed by the body of fan blade 400. Cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G reduce the overall weight of fan blade 400 compared to a same size and shape airfoil without cavities. In Figure 4 In the illustrated example of FIG. 4, the cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G are not uniform in size and shape. In other examples, cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G can have a uniform size and shape. In some examples, the shape of cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G, ribs 406A, 408A, 406B, 408B, 406C, 408C, 406D, 408D, 406E, 408E, 406F, and 408F, and / or interfaces 410A, 410B, 410C, 410D, 410E, 410F can be designed to reduce the likelihood of fan blade 400 vibrating in a critical vibration mode.

[0034] Ribs 406A, 406B, 406C, 406D, 406E, 406F are features (e.g., bosses, protrusions, etc.) of cap 404 that are capable of forming interfaces 410A, 410B, 410C, 410D, 410E, 410F. Ribs 408A, 408B, 408C, 408D, 408E, 408F are features (e.g., bosses, protrusions, etc.) of body 402 that are capable of forming interfaces 410A, 410B, 410C, 410D, 410E, 410F. In Figure 3 In the illustrated example of FIG. 4, interfaces 410A, 410B, 410C, 410D, 410E, 410F are formed by the ribs 406A, 406B, 406C, 406D, 406E, 406F of cap 404 and the ribs 408A, 408B, 408C, 408D, 408E, 408F of body 402 abutting, are slip joints. In Figure 5 In the illustrated example of FIG. 4, interfaces 410A, 410B, 410C, 410D, 410E, 410F are oriented in a plane that is substantially perpendicular to first face 212. During operation of fan blade 400, interfaces 410A, 410B, 410C, 410D, 410E, 410F cause cap 404 and body 402 to slide and / or rub, which rubs dampen fan blade 200. In particular, vibration energy of fan blade 200 is dissipated (e.g., as heat, etc.) by the friction and / or sliding of interfaces 410A, 410B, 410C, 410D, 410E, 410F.

[0035] Figures 2-4 A unit structure 500 that can be used with the fan blades 200, 400 of Figure 5 is shown. In the illustrated example of Figure 6 , the unit structure 500 includes an inner structure 502 and an outer structure 504. In some examples, the unit structure 500 can be placed in the cavities 306A, 306B, 306C, 306D, 306E, 306F, 306G of the fan blade 200 and / or the cavities 404A, 404B, 404C, 404D, 404E, 404F, 404G of the fan blade 400. In other examples, the unit structure 500 can be disposed in the center of the fan blade. In some examples, the fan blade and the unit structure 500 can be formed by additive manufacturing (e.g., three-dimensional printing, powder bed fusion, etc.). In some examples, the inner structure 502 and the outer structure 504 can slide and / or rub against each other during operation of the fan blade 200, 400, which frictionally inhibits the fan blade 200, 400.

[0036] Figures 2-4 is a flowchart illustrating operations 600 that can be used to manufacture the fan blades 200, 400 of Figure 2 . While the operations 600 are described primarily with reference to the fan blade 200 of Figure 3 and Figure 3 , the operations 600 can be used to manufacture any other fan blade described herein.

[0037] At block 602, a airfoil body 216 is formed. An example airfoil body 216 includes a recessed portion 222 having a first feature and a lip 302. For example, the first feature can include the body ribs 310A, 310B, 310C, 310D, 310E, 310F of Figure 3 . For example, the airfoil body 216 can be formed by additive manufacturing and / or machining. At block 604, an airfoil cap 218 is formed. The airfoil cap 218 includes a second feature. For example, the first feature can include the ribs 308A, 308B, 308C, 308D, 308E, 308F of ​ .

[0038] At block 606, an airfoil cap 218 is disposed within the recessed portion 222 of the airfoil body 216 to form a complete fan blade 200. In some examples, the airfoil cap 218 can be disposed on the lip 302 such that interfaces 312A, 312B, 312C, 312D, 312E, 312F are formed. The airfoil cap 218 is placed in the airfoil body 216 so the first face 212 is level (e.g., flush, etc.). In some examples, the cap 218 can be retained by one or more adhesives, one or more adhesive press fits, one or more shrink fits, one or more welds, and / or combinations thereof. Additionally or alternatively, the coupling of the cap 218 and the airfoil body 216 can result in any other suitable number of interfaces and / or joints (e.g., slip joints, sandwich joints, etc.). In certain examples, the friction at the interfaces 312A, 312B, 312C, 312D, 312E, 312F can dampen the fan blade 200 during operation of the fan blade 200, which reduces the vibrational response of the fan blade 200. At block 608, the fan blade 200 is coupled within the gas turbine engine 100. For example, the dovetail of the fan blade 200 can be coupled to a corresponding slot of a disk associated with the fan section 106. In other examples, the fan blade 200 can be coupled to the gas turbine engine 100 by any other suitable means.

[0039] Disclosed herein are fan blades having internal damping structures. Compared to existing fan blades, examples disclosed herein reduce the weight of the fan blade and provide superior frictional damping. Examples disclosed herein improve the vibrational response and flutter response of the fan blade and reduce the likelihood of the fan blade vibrating in a critical mode.

[0040] Further aspects of the present disclosure are provided by the subject matter of the following clauses:

[0041] Example 1 includes an airfoil disposed within a flow path of a gas turbine engine, the airfoil comprising an airfoil body having a first face, a second face, and a recessed portion formed in the second face; and an airfoil cap having a first surface, the airfoil cap disposed within the recessed portion, the first surface substantially flush with the second face.

[0042] Example 2 includes the airfoil of example 1, further comprising a joint formed by a first feature of the airfoil cap and a second feature of the recessed portion, the joint functioning as a frictional damper of the airfoil.

[0043] Example 3 includes the airfoil of any preceding clause, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a slip joint formed by an interface between the first rib and the second rib.

[0044] Example 4 includes the airfoil of any preceding paragraph, wherein the interface is oriented in a plane substantially perpendicular to the first face.

[0045] Example 5 includes the airfoil of any preceding paragraph, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a sandwich joint formed by the interface between the first rib and the second rib.

[0046] Example 6 includes the airfoil of any preceding paragraph, wherein the interface is oriented substantially parallel to the first face.

[0047] Example 7 includes the airfoil of any preceding paragraph, wherein the recessed portion of the second face includes a lip, the lip abutting a fourth face of the airfoil cap.

[0048] Example 8 includes a gas turbine engine comprising a fan section and an airfoil disposed within the fan section, the airfoil comprising an airfoil body comprising a first face and a second face comprising a recessed portion; and an airfoil cap comprising a first surface, the airfoil cap disposed within the recessed portion, the first surface substantially flush with the second face.

[0049] Example 9 includes the gas turbine engine of any preceding paragraph, wherein the airfoil further comprises a joint formed by a first feature of the airfoil cap and a second feature of the recessed portion, the joint functioning as a friction damper for the airfoil.

[0050] Example 10 includes the gas turbine engine of any preceding paragraph, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a slip joint formed by the interface between the first rib and the second rib.

[0051] Example 11 includes the gas turbine engine of any preceding paragraph, wherein the interface is oriented in a plane substantially perpendicular to the first face.

[0052] Example 12 includes the gas turbine engine of any preceding paragraph, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a sandwich joint formed by the interface between the first rib and the second rib.

[0053] Example 13 includes the gas turbine engine of any preceding paragraph, wherein the interface is oriented in a plane substantially parallel to the first face.

[0054] Example 14 includes the gas turbine engine of any preceding paragraph, wherein the recessed portion of the second face includes a lip, the lip abutting a fourth face of the airfoil cap.

[0055] Example 15 includes a method comprising forming an airfoil body comprising a first face, a second face, and a recessed portion formed in the second face, forming an airfoil cap comprising a first surface, and disposing the airfoil cap within the recessed portion such that the first surface is substantially flush with the second face to form an airfoil.

[0056] Example 16 includes the method of any preceding paragraph, further comprising disposing the airfoil within a flowpath of a gas turbine engine, the gas turbine engine defining an axial axis, a radial axis, and a circumferential axis.

[0057] Example 17 includes the method of any preceding paragraph, wherein disposing the airfoil cap within the recessed portion comprises forming a joint between a first feature of the airfoil body and a second feature of the airfoil cap, the joint acting as a friction damper for the airfoil.

[0058] Example 18 includes the method of any preceding paragraph, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a slip joint formed by an interface between the first rib and the second rib.

[0059] Example 19 includes the method of any preceding paragraph, wherein the first feature is a first rib, the second feature is a second rib, and the joint is a sandwich joint formed by an interface between the first rib and the second rib.

[0060] Example 20 includes the method of any preceding paragraph, wherein disposing the airfoil cap within the recessed portion comprises abutting a fourth surface of the airfoil cap with a lip of the airfoil body.

[0061] The appended claims are hereby incorporated into this detailed description, wherein each claim stands as a separate embodiment of this disclosure.

Claims

1. An airfoil disposed within a flowpath of a gas turbine engine, characterized in that, The airfoil includes: an airfoil body including: a first face; and a second face including a recessed portion; and an airfoil cap including a first surface, the airfoil cap disposed within the recessed portion, the first surface substantially flush with the second face; a joint formed by an interface between a first integral feature of the airfoil cap and a second integral feature of the recessed portion, the interface oriented in a plane substantially perpendicular to the first face.

2. The airfoil of claim 1, wherein, wherein the joint functions as a friction damper for the airfoil.

3. The airfoil of Claim 2, wherein, wherein the first integral feature is a first rib, the second integral feature is a second rib, and the joint is a slip joint.

4. The airfoil of claim 1, wherein, wherein the recessed portion of the second face includes a lip, the lip abutting a fourth face of the airfoil cap.

5. A gas turbine engine characterized by, including: a fan section; and an airfoil disposed within the fan section, the airfoil including: an airfoil body including: a first face; and a second face including a recessed portion; and an airfoil cap including a first surface, the airfoil cap disposed within the recessed portion, the first surface substantially flush with the second face; a joint formed by an interface between a first integral feature of the airfoil cap and a second integral feature of the recessed portion, the interface oriented in a plane substantially perpendicular to the first face.

6. The gas turbine engine of claim 5, wherein, wherein the joint functions as a friction damper for the airfoil.

7. The gas turbine engine of claim 6, wherein, wherein the first integral feature is a first rib, the second integral feature is a second rib, and the joint is a slip joint.

8. The gas turbine engine of claim 5, wherein, wherein the recessed portion of the second face includes a lip, the lip abutting a fourth face of the airfoil cap.

9. A method characterized by, including: forming an airfoil body including a first face, a second face, and a recessed portion formed in the second face; forming an airfoil cap including a first surface; and disposing the airfoil cap within the recessed portion such that the first surface is substantially flush with the second face to form an airfoil, the disposing of the airfoil cap including forming a joint between a first integral feature of the airfoil body and a second integral feature of the airfoil cap.

10. The method of claim 9, wherein, further including disposing the airfoil within a flowpath of a gas turbine engine, the gas turbine engine defining an axial axis, a radial axis, and a circumferential axis.

11. The method of claim 9, wherein, wherein the joint functions as a friction damper for the airfoil.

12. The method of claim 11, wherein, wherein the first integral feature is a first rib, the second integral feature is a second rib, and the joint is a slip joint.

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