Lightweight fan housing construction for energy absorption

Abstract

Lightweight fan case constructions for energy absorption are disclosed herein. An apparatus includes a first set of metal bands positioned within a containment case of a turbofan engine, and a second set of metal bands traversing the first set of metal bands, the first set of metal bands and the second set of metal bands surrounding at least a portion of the turbofan engine.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to turbofan engines, and more particularly, to lightweight fan case constructions for energy absorption. BACKGROUND

[0002] Aircrafts sometimes encounter situations that compromise the thrust capabilities of associated propellers, such as when fan blades of a propeller break and / or release from an associated retaining disk (e.g., a fan blade out situation). The thrust capabilities of an aircraft are critical to the functionality of the aircraft and the safety of its passengers. Accordingly, when a fan blade out situation occurs, the aircraft typically utilizes protection to limit damage to the propeller and associated components. SUMMARY

[0003] A lightweight fan case construction for energy absorption is disclosed.

[0004] Certain examples provide an example apparatus comprising a first set of metal bands positioned within a containment case of a turbofan engine, and a second set of metal bands traversing the first set of metal bands, the first set of metal bands and the second set of metal bands surrounding at least a portion of the turbofan engine.

[0005] Certain examples provide an example case apparatus comprising a first portion of a containment case of a turbofan engine, a second portion of the containment case, and a protruding portion of the containment case between the first portion and the second portion, the protruding portion comprising a structural lattice.

[0006] Certain examples provide an apparatus comprising a containment case of a turbofan engine, and a trench filler of the turbofan engine between the turbofan engine and the containment case, the trench filler comprising: a first layer comprising a solid metal; and a second layer comprising at least one of a lattice structure, air, or a fluid, the first layer and the second layer surrounding at least a portion of the turbofan engine, the first layer and the second layer alternating in a radial direction. BRIEF DESCRIPTION OF DRAWINGS

[0007] FIG. 1 illustrates a schematic cross-sectional view of a prior art example of a turbofan engine.

[0008] Figure 2 An example containment case and / or trench filler of a turbofan engine is illustrated.

[0009] Figure 3 An example containment case and / or trench filler of Figure 2 is illustrated.

[0010] Figure 4A An example containment case and / or trench filler of Figure 2Example impact load simulation of an example containment case of and / or 3 and / or an example containment case of the prior art turbofan engine of FIG. 1.

[0011] Figure 5 An example cross-sectional view of an example containment case of a turbofan engine is shown.

[0012] Figure 6 An example cross-sectional view of an example containment case of a turbofan engine is shown. Figure 2 , 3 An example axial cross-sectional view of an example containment case of and / or 5 of a turbofan engine is shown.

[0013] Figure 7A -B shows a portion of an example containment case of a turbofan engine.

[0014] Figure 8A -B shows Figure 7A An example deflector plate of an example containment case of a turbofan engine of -B is shown.

[0015] The drawings are not to scale. Instead, the thickness of the layers or regions in the drawings can be exaggerated for the purpose of clarity. Generally, the same reference numbers will be used throughout the drawings and accompanying written description to refer to the same or like parts. As used herein, a connection reference (e.g., attached, coupled, connected, and joined) can include an intermediate member between the element(s) being connected reference by the connection reference and / or relative movement between those elements, unless otherwise stated. As a result, a connection reference does not necessarily infer that two elements are directly connected and / or have a fixed relationship with each other. As used herein, a statement that any part is “in contact” with another part is defined as meaning that there are no intermediate parts between those two parts.

[0016] Unless specifically stated otherwise, as used herein, descriptors such as “first,” “second,” “third,” etc., do not assign or otherwise imply any meaning, priority, physical order, arrangement in a list, and / or any other ordering, but are merely used as labels and / or arbitrary names to distinguish elements so as to facilitate understanding of the disclosed examples. In some examples, a 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 cases, it is understood that such descriptors are used only to clearly identify those elements that can otherwise share the same name, for example. DETAILED DESCRIPTION

[0017] A turbofan engine includes a containment case having a hard or soft wall that circumferentially surrounds the turbofan. The hard wall containment case includes a thick metal or composite skin, while the soft wall containment case includes a thinner metal or composite wall and / or a large Kevlar TMFibers. Soft-wall containment casings can address some of the issues that exist with hard-wall containment casings. For example, soft-wall containment casings can absorb some of the impact force from a fan blade off (FBO) event. Additionally, soft-wall containment casings generally include a reduced weight as compared to hard-wall containment casings. As a result, soft-wall containment casings require less support material, which reduces the costs associated therewith. Additionally, the reduced weight of the casing and support structure can reduce fuel consumption during turbofan operation. However, soft-wall containment casings lack the structural strength of hard-wall containment casings and require a large empty volume around the casing to allow for deflection and capture of a released blade during an FBO event, thereby removing it from the flow path that can cause further damage to the engine. Additionally, turbofan engines that include multi-stage fan blades generally require a metal hard-wall containment casing to provide the necessary structural support.

[0018] In some examples, hard-wall containment casings include additional structures and / or materials to be able to absorb impacts in the event of an FBO. For example, hard-wall containment casings can include a rigid fan case, such as a Kevlar® TM or composite skin to achieve impact absorption. However, the rigid fan case or composite skin adds additional weight to the hard-wall containment casing, which requires additional structural support and increases fuel burn.

[0019] To address some of the issues that exist with known containment casings, examples disclosed herein provide a lightweight fan casing construction for energy absorption. In some examples, the containment casing, trench filler, and / or structures associated therewith protect a turbofan engine when an FBO event occurs. In such examples, the containment casing, trench filler, and / or structures associated therewith minimize the weight associated with protecting the turbofan engine and, in turn, minimize and / or otherwise reduce fuel burn and / or support structures associated with the turbofan engine.

[0020] In some examples, the containment casing includes a first set of metal bands and a second set of metal bands that traverse the first set of metal bands. In such examples, the first set of metal bands and the second set of metal bands surround at least a portion of the turbofan engine. In some examples, the first set of metal bands and the second set of metal bands are arranged to form an internal truss and / or ribbed structure. In such examples, the first set of bands and the second set of bands are coupled via a joining process (e.g., welding, riveting, bolting, brazing, etc.).

[0021] In some examples, the truss and / or ribbed structure includes at least one layer and / or level of a first set of strips and a second set of strips disposed along a circumference of the containment housing. For example, the truss and / or ribbed structure can be positioned along an inner circumference and / or an outer circumference of the containment housing. In some examples, the size (e.g., width, thickness, length, etc.) and / or geometric architecture (e.g., geometric spacing, angular orientation, etc.) of the first set of strips and the second set of strips within the truss and / or ribbed structure is configured based on the implementation area within the turbofan engine and / or the containment housing. For example, multiple layers of the first set of strips and the second set of strips can be positioned in predetermined areas of the containment housing to increase the impact absorption and / or stiffness of the containment housing. In some examples, the first set of strips and the second set of strips alternate between different layers and / or levels. In some examples, the first set of strips and the second set of strips form a single layer and / or level.

[0022] In some examples, the containment housing includes at least two different metals. For example, the containment housing can include aluminum lithium strips (e.g., first set of strips, second set of strips) sandwiched between aluminum lithium or aluminum sheets that have a higher impact toughness than aluminum with the same density. Thus, the aluminum lithium strips increase the impact toughness and energy absorption of the containment housing while maintaining its weight and / or stiffness. Thus, the containment housing can be used in place of a composite fan case to maintain the weight of a soft wall fan case while providing significant cost reduction and improved protection.

[0023] In some examples, the deflector plate is coupled to an outer surface of the containment housing. In such examples, the deflector plate deflects and / or absorbs the impact of loose fan blades that separate from an associated retaining disk. For example, a first end of the deflector plate can be coupled to the containment housing while a second end of the deflector plate is unattached to deflect objects away from the containment housing. In some examples, for example, the deflector plate is positioned on a predetermined portion of the outer surface to provide protection for components outside of the turbofan engine, such as a gearbox and / or full authority digital engine control (FADEC) and associated components.

[0024] In some examples, the containment housing and / or the trench fill of the containment housing includes a structural lattice, air, and / or fluid positioned between solid layers (e.g., aluminum lithium strips, metal sheets, composite sheets, etc.). In some examples, the structural lattice layers, air layers, or fluid layers alternate between the solid layers to form a multi-layer containment housing. In addition to being used for hard wall or soft wall containment housings and / or trench fills, the multi-layer containment housing can also be implemented in compressor housings, turbine housings, and / or turbocharger housings.

[0025] In some examples, the structural lattice is a gyroid structure produced through additive manufacturing. In such examples, the gyroid structure includes metal (e.g., aluminum, aluminum lithium, titanium, steel, etc.), Kevlar TM or a polymer composite. In comparison to honeycomb structures or solid metals, the gyroid structure provides greater energy absorption capabilities. As a result, when an FBO event occurs, the gyroid structure absorbs more energy from loose fan blades and / or pieces thereof in comparison to honeycomb structures or solid metals, which minimizes damage caused by the FBO event. Moreover, the thickness of the gyroid structure corresponds to its stiffness, and thus, the thickness of the gyroid structure can be configured based on the implementation area to provide appropriate stiffness to individual segments of the containment case and / or the trench filler.

[0026] In some examples, the structural lattice includes a variable volume fraction for customizing stiffness and weight. In some examples, the structural lattice and / or the foam structure is configured based on the implementation area within the containment case and / or the trench filler. For example, segments of the containment case and / or the trench filler that are susceptible to impact during an FBO event, such as portions aligned with fan blades, can include a gyroid structure having a lower volume fraction. As a result, the gyroid structure absorbs pieces from the FBO event and prevents and / or otherwise reduces damage to the turbofan engine. Moreover, other segments of the containment case and / or the trench filler can include a gyroid structure having a higher volume fraction to maintain stiffness of the containment case for structural support.

[0027] In some examples, the containment case includes a front portion, a rear portion, and a protruding portion between the front portion and the rear portion. In some examples, the protruding portion includes a structural lattice to provide energy absorption capabilities to the containment case. For example, the protruding portion can be aligned with fan blades of the turbofan engine to absorb pieces of the fan blades in response to occurrence of an FBO event, which prevents further damage to other areas of the turbofan engine. Moreover, the protruding portion can provide stiffness to the containment case. As a result, the thickness of the front portion and / or the rear portion can be reduced, which offsets and / or otherwise minimizes weight added to the containment case by the protruding portion. Moreover, an inner circumference of the protruding portion can include a layer of abradable material to prevent abrasion of the structural lattice due to friction caused by rotation of the fan blades.

[0028] Referring now to the accompanying drawings, FIG1 is a schematic cross-sectional view of a prior art example of a turbofan engine (e.g., an aircraft engine) 100 that can be combined with various examples disclosed herein. As shown in FIG1, the aircraft engine 100 defines a longitudinal or axial centerline axis 102 extending therethrough for reference. Typically, the turbofan engine 100 may include a core turbine or core turbine engine 104 disposed downstream of a fan section 106.

[0029] The core turbine engine 104 typically includes a generally tubular outer casing 108 defining an annular inlet 110. The casing 108 may be formed of multiple segments. The casing 108 surrounds a compressor section, a combustion section 116, a turbine section, and an exhaust section 122 in a series flow relationship. The compressor section has a supercharger or low-pressure compressor 112 (“LP compressor 112”) and a high-pressure compressor 114 (“HP compressor 114”), and the turbine section has a high-pressure turbine 118 (“HP turbine 118”) and a low-pressure turbine 120 (“LP turbine 120”). A high-pressure shaft or spool 124 (“HP shaft 124”) drivesably connects the HP turbine 118 and the HP compressor 114. A low-pressure shaft or spool 126 (“LP shaft 126”) drivesably connects the LP turbine 120 and the LP compressor 112. The LP shaft 126 may also be connected to a fan shaft or spool 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 130 (i.e., an indirect drive or gear drive configuration).

[0030] As shown in Figure 1, the fan section 106 includes a plurality of fan blades 132 (“fan” 132) coupled to and extending radially outward from the fan shaft 128. An annular housing 134 circumferentially surrounds at least a portion of the fan section 106 and / or the core turbine engine 104. In some examples, the housing 134 is a rigid-walled housing comprising solid metal. In some other examples, the housing 134 is a soft-walled housing comprising a foam honeycomb structure, a composite structure, and / or Kevlar. TM Enclosure. The housing 134 can be supported relative to the core turbine engine 104 by means of the front mounting 136. In addition, the downstream section 138 of the housing can surround the outer portion of the core turbine engine 104 to define a bypass airflow passage 140 therebetween.

[0031] As shown in FIG. 1, air 142 enters an intake or inlet portion 144 of the turbofan engine 100 during operation of the turbofan engine 100. A first portion 146 of the air 142 flows into a bypass flow passage 140, while a second portion 148 of the air 142 flows into an inlet 110 of the LP compressor 112. One or more sequential stages of LP compressor stator vanes 150 and LP compressor rotor blades 152 (e.g., turbine blades) coupled to the LP shaft 126 progressively compress the second portion 148 of the air 142 flowing through the LP compressor 112 to be directed to the HP compressor 114. Next, one or more sequential 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 the compressed air 158 is mixed with fuel and combusted to provide combustion gases 160.

[0032] The combustion gases 160 flow through the HP turbine 118, where one or more sequential 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 therefrom. 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 sequential 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.

[0033] In addition to aircraft, in land-based turbines and / or turbojet engines, the turbofan engine 100 is used for similar purposes and sees similar environments, where the ratio of the first portion 146 of the air 142 to the second portion 148 of the air 142 is less than that of a turbofan. In each turbofan and turbojet 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.

[0034] As depicted therein, the turbofan engine 100 defines an axial direction A, a radial direction R, and a circumferential direction C. Generally, the axial direction A extends generally parallel to the axial centerline axis 102, the radial direction R extends orthogonally outward from the axial centerline axis 102, and the circumferential direction C extends concentrically about the axial centerline axis 102.

[0035] Figure 2 A portion of a turbofan engine (e.g., an aircraft engine, a gas turbine engine, a turbojet engine, etc.) 200 is shown. In Figure 2 particular, the turbofan engine 200 includes a containment housing 202, a trench filler 204, and fan blades 206. In Figure 2 particular, the containment housing 202 and / or the trench filler 204 can be used as a hard or soft walled containment housing (e.g., the containment housing 134), a turbocharger containment housing, and / or a compressor and / or turbine housing (e.g., the outer housing 108) that is located inside the containment housing 202 and the trench filler 204. In some examples, the containment housing 202 and / or the trench filler 204 are produced by additive manufacturing (e.g., three-dimensional (3-D) printing).

[0036] Figure 2 The illustrated example of FIG. 1 includes an enlarged view 208 of the containment housing 202 and / or the trench filler 204. In Figure 2 particular, the containment housing 202 and / or the trench filler 204 include alternating first layers 210 and second layers 212. In Figure 2 particular, the first layers 210 include a solid metal, such as a sheet or plate of aluminum, aluminum lithium, titanium, and / or steel, etc. In some examples, an inner surface of the first layers 210 include an abradable coating to prevent wear caused by friction from rotation of the plurality of fan blades 206.

[0037] In Figure 2 particular, the second layers 212 include a lattice structure (e.g., a gyroid structure), air, and / or a fluid (e.g., a Newtonian fluid or a non-Newtonian fluid). In some examples, the second layers 212 include air and / or a fluid to minimize a weight and / or a cost of the containment housing 202 and / or the trench filler 204. In such examples, a geometry (e.g., a thickness, a number of layers, an orientation, a spacing, etc.) of the first layers 210 can provide a stiffness to the containment housing 202. In some examples, the second layers 212 include a lattice structure to control a stiffness and / or a weight of the containment housing 202 and / or the trench filler 204. In such examples, properties (e.g., a size, a density, a volume fraction, etc.) of the lattice structure can tailor the stiffness and / or the weight based on an implementation area, as further discussed in connection with Figure 3 FIG. 2.

[0038] In Figure 2 particular, the containment housing 202 and / or the trench filler 204 contain the fan blades 206 and / or fragments thereof when an FBO event occurs. In Figure 2In this configuration, the second layer 212 provides energy absorption capacity for the housing 202 and / or the groove filler 204. In some examples, the helical icosahedral structure provides greater energy absorption compared to solid metal plates and / or conventional honeycomb structures. As a result, the housing 202 and / or the groove filler 204 absorb more kinetic energy from the loose fan blades 206 and / or their fragments compared to the housing 134 of FIG. 1, which reduces damage to the turbofan engine 200 in the event of an FBO event.

[0039] Figure 3 It shows Figure 2 Example configuration 300 that accommodates housing 202 and / or groove filler 204. Figure 3 In this configuration, the housing 202 and / or groove filler 204 includes a first section (e.g., also referred to as the front section or front portion) 302, a second section (e.g., also referred to as the fan blade section or middle portion) 304, and a third section (e.g., the rear section, rear portion) 306. Figure 3 In this example, the second segment 304 is located between the first segment 302 and the third segment 306. The example also includes... Figure 2 The fan blades are 206. Figure 3 In the middle, the second section 304 crosses the plane of rotation of the fan blade 206.

[0040] exist Figure 3 In the first segment 302, a first helical icosahedral structure 308 is included; in the second segment 304, a second helical icosahedral structure 310 is included; and in the third segment, a third helical icosahedral structure 312 is included. Figure 3 In this embodiment, the first helical icosahedral structure 308 has a higher volume fraction than the third helical icosahedral structure 312 to handle the different loads encountered by the first and third segments 302, 306. Specifically, the higher volume fraction of the first helical icosahedral structure 308 achieves higher bending stiffness than the third helical icosahedral structure 312 to handle the higher loads encountered by the first segment 302 compared to the third segment 306. In some other examples, the first helical icosahedral structure 308 and the third helical icosahedral structure 312 have the same volume fraction. Figure 3 In the process, the volume fractions of the first helical icosahedral structure 308 and the third helical icosahedral structure 312 are used to customize the stiffness of the housing 202.

[0041] exist Figure 3In particular embodiments, the second gyroid structure 310 includes a lower volume fraction than the first gyroid structure 308 and the third gyroid structure 312. As such, the second section 304 can provide greater energy absorption than the first section 302 and the third section 306 when an FBO event occurs. Accordingly, the energy absorption provided by the second section 304 minimizes or otherwise reduces the kinetic energy of loose fan blades 206 and / or fragments thereof that can damage components of a turbofan engine (e.g., the core turbofan engine 104 of FIG. 1) deflected away from the trench filler 204 and / or containment housing 202 from occurring. In turn, the second section 304 prevents and / or otherwise reduces damage to other components of the turbofan engine 200. Accordingly, the trench filler 204 and / or containment housing 202 can absorb energy through the second section 304 while maintaining structural support through the first section 302 and the third section 306. Thus, the containment housing 202 and / or the trench filler 204 can provide improved energy absorption when an FBO event occurs as compared to some known hardwall containment housings (e.g., the containment housing 134 of FIG. 1).

[0042] Figure 4A -B illustrates a first impact load simulation 400 including an example impact load 402 encountered by the containment housing 202 and / or the trench filler 204 when an FBO event occurs. Figure 4A FIG. 4 illustrates the gyroid structure (e.g., the first gyroid structure 308, the second gyroid structure 310, the third gyroid structure 312) 404 of the containment housing 202 and / or the trench filler 204 of FIG. 1 and / or 3 prior to encountering an impact load (e.g., an FBO event impact load) 402. Figure 2 and / or 3 prior to encountering an impact load (e.g., an FBO event impact load) 402. Figure 4B illustrates the gyroid structure 404 after encountering the impact load 402. In particular embodiments, the gyroid structure 404 is compressed to absorb the impact load 402 and, thus, the kinetic energy from the fan blades (e.g., the fan blades 206) and / or fragments thereof when an FBO event occurs. Figure 4A -B illustrates the gyroid structure 404 after encountering the impact load 402. In particular embodiments, the gyroid structure 404 is compressed to absorb the impact load 402 and, thus, the kinetic energy from the fan blades (e.g., the fan blades 206) and / or fragments thereof when an FBO event occurs.

[0043] In particular embodiments, the gyroid structure 404 of the containment housing 202 and / or the trench filler 204 of FIG. 1 and / or 3 is a gyroid structure that is not a gyroid. Figure 4BIn particular, the compression of the gyroid 404 limits damage to the containment case 202 and / or the trench filler 204 that maintains its structure. In turn, the containment case 202 and / or the trench filler 204 can maintain the rigidity of the turbofan engine 200 to prevent further issues from damage caused by the FBO event. In some examples, a fan blade 206 or a fragment thereof is embedded into the gyroid 404 during the FBO event. Thus, the gyroid 404 minimizes or otherwise reduces the damage encountered by the turbofan engine when the FBO event occurs.

[0044] Figure 4C -D illustrates a second impact load simulation 410. Figure 4C A honeycomb structure 406 of the containment case 134 of the prior art example aircraft engine 100 of FIG. 1 is illustrated prior to encountering the impact load 402. Figure 4D The honeycomb structure 406 is illustrated after encountering the impact load 402. In Figure 4D In particular, the honeycomb structure 406 absorbs more energy from the impact load 402 than the gyroid 404 of FIG. 3-B. As a result, the honeycomb structure 406 is more likely to deflect a loose fan blade (e.g., the plurality of fan blades 132 of FIG. 1) and / or a fragment thereof away from the core turbine engine 104 when the FBO event occurs. Figure 4A The honeycomb structure 406 of FIG. 3-A absorbs more energy from the impact load 402 than the solid metal structure 408 of FIG. 3-C. As a result, the honeycomb structure 406 is more likely to deflect a loose fan blade (e.g., the plurality of fan blades 132 of FIG. 1) and / or a fragment thereof away from the core turbine engine 104 when the FBO event occurs. Figure 4D In particular, the impact load 402 causes the honeycomb structure 406 to significantly rupture and / or deform. As a result, a fan blade (e.g., the plurality of fan blades 132 of FIG. 1) or a fragment thereof can pass through the honeycomb structure 406 and damage components associated with the aircraft engine 100 outside of the outer case 108. Furthermore, fragments of the honeycomb structure 406 can break off due to the impact load 402 and cause further damage to the aircraft engine 100. In some examples, the deformation of the honeycomb structure 406 reduces the rigidity of the containment case 134, which can cause the containment case 134 to rupture in response to encountering the load.

[0045] Figure 4E -F illustrates a third impact load simulation 420. Figure 4E A solid metal structure 408 of the containment case 134 of the prior art example aircraft engine 100 of FIG. 1 is illustrated prior to encountering the impact load 402. Figure 4F The solid metal structure 408 is illustrated after encountering the impact load 402. In Figure 4F In particular, the solid metal structure 408 encounters minimal compression from the impact load 402. As a result, the solid metal structure 408 absorbs less energy from the impact load 402 than the gyroid 404. Thus, the solid metal structure 408 deflects loose fan blades (e.g., the plurality of fan blades 132 of FIG. 1) and / or fragments thereof when the FBO event occurs without significantly absorbing kinetic energy from the impact, which allows the loose fan blades and / or fragments thereof to damage other components of the aircraft engine 100, such as the core turbine engine 104.

[0046] Figure 5 An example cross-sectional view of a containment housing 500 of a turbofan engine is shown. The containment housing 500 can be used as an advantageous replacement of the containment housing 134 of the turbofan engine 100 of FIG. 1. Further, the containment housing 500 can be used as the containment housing 202 of Figure 2 and / or 3. In Figure 5 , the containment housing 500 includes a first portion (e.g., a front portion) 502, a second portion (e.g., a protruding portion, a bubble portion, a middle portion) 504, and a third portion (e.g., a rear portion) 506. In Figure 5 , the protruding portion 504 includes an outer wall 508, an inner wall 510, and a structural lattice 512. In Figure 5 , the containment housing 500 includes a first radius 514 extending from an axis of rotation 516 of a fan blade (e.g., the fan blade 206) to an inner surface (e.g., an inner surface of the inner wall 510) of the containment housing 500. In Figure 5 , the protruding portion 504 includes a second radius 518 extending from a center 520 of the inner wall 510 to the outer wall 508.

[0047] In Figure 5 , the protruding portion 504 circumferentially surrounds fan blades (e.g., the fan blades 132 of FIG. 1, Figure 2 the fan blades 206 of 3) of a turbofan engine. In some examples, one or more of the protruding portions 504 are aligned with one or more fan blades. In Figure 5 , the protruding portion 504 includes a curvature in two geometric planes (e.g., in the circumferential direction C and the axial direction A). In Figure 5 , the inner wall 510 is an abradable layer that prevents wear caused by friction resulting from rotation of the fan blades. In Figure 5 , the outer wall 508 includes a first thickness, and the inner wall 510 includes a second thickness. In some examples, the second thickness is thinner than the first thickness.

[0048] In Figure 5 , the structural lattice 512 is located between the outer wall 508 and the inner wall 510. In some examples, the structural lattice 512 includes a gyroid structure (e.g., the second gyroid structure 310). In Figure 5In some examples, the structural lattice 512 provides energy absorption capability to the containment housing 500. In some examples, when an FBO event occurs, loose fan blades and / or fragments thereof penetrate the inner wall 510 and impact the structural lattice 512. In such examples, the structural lattice 512 can absorb the impact and contain the loose fan blades and / or fragments thereof to protect other components of the turbofan engine. The structural lattice 512 includes a significant density to prevent the loose fan blades and / or portions thereof from exiting the protruding portion 504 and damaging other components of the turbofan engine. In some examples, when a fragment of a loose fan blade penetrates a front region or a rear region (e.g., a shallower portion) of the structural lattice 512 with sufficient kinetic energy to impact the outer wall 508, the curvature of the outer wall 508 deflects the fragment into another portion of the structural lattice 512, which in turn contains the fragment to protect components of the turbofan engine. In some examples, an inner portion of the structural lattice 512 includes a first volume fraction, and an outer portion of the structural lattice 512 includes a second volume fraction that is less than the first volume fraction. In such examples, the inner portion of the structural lattice 512 provides impact absorption capability, containment capability, and additional structural stiffness to the containment housing 500.

[0049] In Figure 5 some examples, the containment housing 500 is a hard-walled containment housing that provides the advantages of a soft-walled containment housing. For example, in Figure 5 some examples, the structural lattice 512 provides energy absorption capability and stiffness to the containment housing 500. Due to the stiffness provided by the structural lattice 512, the thickness of the first portion 502 and the second portion 506 of the containment housing 500 can be reduced relative to the thickness of the containment housing 134 of FIG. 1. In turn, the protruding portion 504 provides protection to the turbofan engine while maintaining a desired weight and / or stiffness of the containment housing 500. In some examples, the protruding portion 504 is integrated into an existing containment housing by a bonding method.

[0050] Figure 6 FIG. 1 illustrates a volume fraction and / or density configuration of a containment housing and / or trench filler 600. The volume fraction and / or density configuration of the containment housing and / or trench filler 600 can be used in Figure 2 and 3 the containment housing 202 and / or the trench filler 204 of FIG. 1, and / or Figure 5 the structural lattice 512 of FIG. 1. In Figure 6 some examples, the containment housing and / or trench filler 600 includes an abradable layer 602, a lattice structure (e.g., the first, second, and / or third gyroid structures 302, 304, 306, the structural lattice 512) 604, and a housing 606. In Figure 6 some examples, the lattice structure 604 includes a first layer (e.g., an inner layer) 608 and a second layer (e.g., an outer layer) 610.

[0051] exist Figure 6 In the middle, the shell 606 surrounds the second layer 610 of the lattice structure 604. Figure 6 In the middle, the second layer 610 surrounds the first layer 608 of the lattice structure 604. Figure 6 In this structure, the wear-resistant layer 602 is located inside the lattice structure 604 to prevent the lattice structure from being worn by the rotation of the fan blades (e.g., fan blade 206).

[0052] exist Figure 6 In this context, the lattice structure 604 provides energy absorption capacity for housing the shell and / or groove filler 600 to minimize and / or otherwise reduce damage from FBO events. Figure 6 In the first layer 608, a first volume fraction and / or density are included. Figure 6 In the second layer 610, a second volume fraction and / or density is included, which is less than the first volume fraction and / or density. Figure 6 In this configuration, the first layer 608 provides initial shock absorption for loose fan blades and / or their debris. In such an example, the second layer 610 provides additional shock absorption to prevent loose fan blades and / or their debris from leaving the housing and / or groove filler 600, and / or causing further damage to components within the housing and / or groove filler 600. Therefore, the lower volume fraction and / or density of the second layer 610 provides energy absorption while minimizing and / or otherwise reducing the weight of the lattice structure, and thus reducing the weight of the housing and / or groove filler 600.

[0053] exist Figure 6 In this process, the lattice structure 604 is produced through additive manufacturing, which allows the properties of the lattice structure 604 (e.g., structure, stiffness, weight, volume fraction, density, etc.) to correspond to the implementation area within the housing and / or groove filler 600. As a result, the lattice structure 604 can be manufactured based on requirements specific to certain areas of the housing and / or groove filler 600 (e.g., creep, fatigue, elongation, etc.).

[0054] Figure 7A A portion of the turbofan engine 700 is shown. Figure 7A In the turbofan engine 700, a housing 702, a groove filler 704, fan blades 706, and a retaining disc 708 are included. Figure 7A In this configuration, the groove filler 704 is attached to the inner surface of the housing 702. In some examples, Figure 2 The groove filler 204 was used as the groove filler 704. Figure 7A In the middle, fan blade 706 is connected to retaining disc 708. Figure 7ADuring the operation of the turbofan engine 700, the rotation of the retaining disk 708 causes the fan blades 706 to rotate.

[0055] exist Figure 7A In the middle, the housing 702 includes truss and / or rib-like structures, such as combined Figure 7B Further discussion follows. In some examples, the truss and / or rib structure of the housing 702 comprises a hybrid construction of at least two different metals, such as lithium aluminum and aluminum. For example, the housing 702 may include lithium aluminum strips located between aluminum walls. In some examples, the housing 702 comprises an integral construction of lithium aluminum strips within lithium aluminum walls. At the same density, lithium aluminum provides higher impact toughness than aluminum. Therefore, the housing 702 can use less lithium aluminum to provide the same containment capacity as an aluminum housing, resulting in a weight reduction in the housing 702. Consequently, the turbofan engine 700 can be supported with less support material and / or structure, leading to significant cost savings. In some examples, the housing 702 may have a similar weight to a soft-walled composite fan housing. In such examples, the housing 702 can replace a soft-walled composite fan housing at a significantly reduced cost while providing improved containment capacity.

[0056] In some examples, when the turbofan engine 700 ingests a foreign object, the object impacts the fan blade 706 and / or the retaining disc 708, causing the fan blade 706 and / or fragments thereof to detach from the retaining disc 708 (e.g., an FBO event occurs). Figure 7A In this process, the rotational speed of the fan blades 706 causes the fan blades 706 and / or fragments thereof to be launched outwards along a trajectory toward the groove filler 704 and the housing 702. Figure 7A In the event of an FBO incident, the high impact toughness of the housing 702 prevents the fan blades 706 and / or fragments thereof from leaving the turbofan engine 700 and damaging external components.

[0057] Figure 7B It shows Figure 7A A top view of the cross-section AA of the housing 702. Figure 7B In this housing 702, a first set of metal strips 710, a second set of metal strips 712, and walls 714 are included. In some examples, the first set of metal strips 710 and the second set of metal strips 712 form the internal structure of the housing 702. Furthermore, a plurality of walls 714 surround the first set of metal strips 710 and the second set of metal strips 712. Figure 7B In this structure, the first group of metal strips 710, the second group of metal strips 712, and multiple walls 714 are connected by a joining method. Figure 7BIn this configuration, the first set of metal strips 710, the second set of metal strips 712, and the wall 714 comprise lithium aluminum. In some examples, certain regions of the housing 702 include the first set of metal strips 710 and the second set of metal strips 712 to provide energy absorption and prevent the fan blades 706 and / or fragments thereof from leaving the housing 702.

[0058] exist Figure 7B In this configuration, a first set of metal strips 710 traverses a second set of metal strips 712. In some examples, the first set of metal strips 710 is positioned on the same plane or level as the second set of metal strips 712. In some examples, the first set of metal strips 710 and the second set of metal strips 712 form alternating layers within the housing 702. In some examples, the first set of metal strips 710 and the second set of metal strips 712 are positioned along the inner and / or outer circumference of the housing 702 for energy absorption and containment during an FBO event. The first set of metal strips 710 and the second set of metal strips 712 may include various lengths, widths, and / or thicknesses based on the implementation area within the housing 702. Figure 7B In this configuration, the structural layout of the first set of metal strips 710 and the second set of metal strips 712 is constructible. For example, the angular orientation of the first set of metal strips 710 relative to the second set of metal strips 712, the spacing between strips 710 and 712, the number of strips 710 and 712, and / or the number of layers formed by strips 710 and 712 can be constructed based on the implementation area within the turbofan engine 700 and / or the housing 702.

[0059] Figure 8A It shows Figure 7A The first embodiment 800 of the deflector plate 802 in the -B turbofan engine 700. In Figure 8A In the middle, the deflection plate 802 includes a first end 804 and a second end 806. Furthermore, Figure 8A Included Figure 7A -B's ridge 808 on the outer surface of the housing 702. Although in this example, the deflection plate 802 is with Figure 7A The housing 702 of the -B type is used together, but the deflector plate 802 can be used with any housing to protect components associated with the turbofan engine. In some examples, the deflector plate 802 provides protection for components outside the soft-walled housing with minimal weight impact.

[0060] exist Figure 8A In this configuration, the first end 804 of the deflection plate 802 is attached to the ridge 808 of the housing 702. For example, the first end 804 can be bolted to the ridge 808. In some examples, the deflection plate 802 is integrally formed with the ridge 808. For example, the deflection plate 802 can be manufactured together with the housing 702 by milling a raised boss. Figure 8AIn this case, the second end 806 of the deflection plate 802 is separated from the housing 702 (e.g., not engaged, not connected, separated, etc.).

[0061] exist Figure 8A In this configuration, the deflector plate 802 is positioned along a portion of the outer surface of the housing 702. In some examples, the deflector plate 802 is aligned with components associated with the turbofan engine 700 (e.g., gearbox and / or FADEC) located outside the housing 702, for example, to provide protection. Figure 8A In this configuration, as the fan blade 706 is released from the retaining disc 708 and propagates through the housing 702, the deflector plate 802 deflects and reduces the velocity of the fan blade 706 and / or its fragments. In some examples, the deflector plate 802 does not completely suppress the trajectory of the fan blade 706 because only the first end 804 is engaged with the housing 702 and the deflector plate 802 is positioned only on a portion of the outer surface of the housing 702. Therefore, the deflector plate 802 deflects the fan blade 706 and / or its fragments away from components associated with the turbofan engine 700 located outside the housing 702, without deflecting the fan blade 706 and / or its fragments back into the turbofan engine 700 to avoid further damage from an FBO event.

[0062] In some examples, the deflector 802 is used with a soft-walled housing, in which case the fan blades 706 and / or fragments thereof will be more likely to encounter the deflector 802 because... Figure 7A Compared to the housing 702 of -B and 8A, the soft-walled housing provides reduced containment capacity. In some examples, the thickness and / or material of the deflector plate 802 is configured to deflect and reduce speed, thereby preventing and / or otherwise minimizing or reducing the impact forces of the fan blade 706 on structures associated with the turbofan engine 700. For example, when the deflector plate 802 is used with the soft-walled housing, the deflector plate 802 may comprise a denser and stronger ductile material than the soft-walled housing, which protects components outside the soft-walled housing, similar to a hard-walled housing, with a lighter weight compared to some hard-walled housings. In some examples, additional structures are integrated with the deflector plate 802 along the outer surface of the housing 702 to contain the fan blade 706 and / or fragments thereof in the event of an FBO event, such as in combination. Figure 8B Further discussion is needed.

[0063] Figure 8B It shows Figure 7A The second embodiment 850 of the deflector plate 802 in the -B turbofan engine 700. Figure 8B In the second embodiment 850, an energy-absorbing layer (e.g., a lattice structure, a honeycomb structure, etc.) 852, a covering layer (e.g., a metal sheet, a composite sheet) 854, and a wrapping layer (e.g., Kevlar)TM wrapping) 856. Figure 8B Further comprising Figure 8A the deflector plate 802 and the ridge 808 of the containment housing 702, and Figure 7A the containment housing 702 of the B and 8A.

[0064] In Figure 8B , the first end 804 of the deflector plate 802 is coupled to the ridge 808 of the containment housing 702. In Figure 8B , the first portion 858 of the energy absorbing layer 852 is located on an outer surface of the containment housing 702 and the second portion 860 of the energy absorbing layer 852 is located on an outer surface of the second end 806 of the deflector plate 802. In Figure 8B , the cover layer 854 is located over the energy absorbing layer 852. In Figure 8B , the cover layer 854 is coupled to the outer surface of the containment housing 702. In Figure 8B , the wrapping layer 856 is located over the cover layer 854 and coupled to the containment housing 702. In Figure 8B , the energy absorbing layer 852, the cover layer 854, and the wrapping layer 856 are disposed on a portion of the containment housing 702 having the deflector plate 802.

[0065] In Figure 8B , the energy absorbing layer 852 includes a thickness capable of absorbing and / or containing the fan blade 706 and / or fragments thereof upon occurrence of an FBO event. In Figure 8B , the cover layer 854 maintains the position of the energy absorbing layer 852. In Figure 8B , the wrapping layer 856 contains the fan blade 706 and / or fragments thereof within the energy absorbing layer 852. For example, upon occurrence of an FBO event, the deflector plate 802 can provide energy absorption and deflect the fan blade 706 and / or fragments thereof into the energy absorbing layer 852. Thus, the energy absorbing layer 852 further absorbs kinetic energy from the fan blade 706 and / or fragments thereof. Additionally, the cover layer 854 maintains the position of the energy absorbing layer 852 as the fan blade 706 and / or fragments thereof travel therethrough. In turn, the wrapping layer 856 deflects the fan blade 706 and / or any fragments thereof that reach the cover layer 854 and / or the wrapping layer 856 back into the energy absorbing layer 852 for additional energy absorption and, in turn, containment. Thus, the deflector plate 802, the energy absorbing layer 852, the cover layer 854, and / or the wrapping layer 856 reduce and / or otherwise minimize damage from FBO events.

[0066] “Comprise” and “contain” (and all forms of these terms) are used herein as open-ended terms. Thus, whenever a claim employs any form of “comprise” or “contain” (e.g., comprises, comprising, include, including, etc.) as a transition term, it is open to the full range of equivalents to that transition term. As used herein, the phrase “at least” is used as an open-ended transition term when, for example, the phrase “at least” is used in the context of a preamble of a claim. As used herein, the term “and / or” when used in the form “A, B, and / or C” means A, B, C individually or any combination or subset of these, for example (1) A only, (2) B only, (3) C only, (4) A with B, (5) A with C, (6) B with C, and (7) A, B, and 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) at least one 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.

[0067] As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude multiple. As used herein, the term “a” or “an” entity refers to one or more 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.

[0068] From the foregoing, it will be appreciated that example methods, apparatus and articles of manufacture have been disclosed that provide for a lightweight fan case construction for energy absorption. More specifically, examples described herein provide for containment casings, trench fillers and / or structures associated therewith that protect a turbofan engine in the event of an FBO event. Moreover, examples disclosed herein minimize the weight impact of the protection provided by the containment casings, trench fillers and / or associated structures to reduce the weight of the turbofan engine, which in turn minimizes fuel burn and / or support structures associated with the turbofan engine.

[0069] Example lightweight fan case constructions for energy absorption are disclosed herein.

[0070] Further examples, and combinations thereof, include the following:

[0071] 1. An apparatus comprising: a first set of metal strips positioned within a containment casing of a turbofan engine; and a second set of metal strips traversing the first set of metal strips, the first set of metal strips and the second set of metal strips surrounding at least a portion of the turbofan engine.

[0072] 2. The apparatus of any preceding clause, wherein the first set of metal strips and the second set of metal strips comprise aluminum lithium.

[0073] 3. The apparatus of any preceding clause, wherein the first set of metal strips and the second set of metal strips are disposed along a circumference within the containment casing.

[0074] 4. The apparatus of any preceding clause, wherein the first set of metal strips is positioned concentrically around the second set of metal strips.

[0075] 5. The apparatus of any preceding clause, further comprising at least a third set of metal strips traversing or surrounding the first set of metal strips and the second set of metal strips.

[0076] 6. The apparatus of any preceding clause, wherein the first set of metal strips and the second set of metal strips are integrated into the containment casing to provide at least one of stiffness or energy absorption.

[0077] 7. The apparatus of any preceding clause, further comprising a deflector plate secured to an outer surface of the containment casing.

[0078] 8. A casing apparatus comprising: a first portion of a containment casing of a turbofan engine; a second portion of the containment casing; and a protruding portion of the containment casing positioned between the first portion and the second portion, the protruding portion comprising a structural lattice.

[0079] 9. The case apparatus of any preceding clause, wherein an inner portion of the structural lattice comprises a first volume fraction and an outer portion of the structural lattice comprises a second volume fraction, the first volume fraction being greater than the second volume fraction.

[0080] 10. The case apparatus of any preceding clause, wherein the protruding portion of the containment case comprises a curvature in two geometric planes.

[0081] 11. The case apparatus of any preceding clause, wherein the protruding portion of the containment case is aligned with fan blades of the turbofan engine.

[0082] 12. The case apparatus of any preceding clause, wherein the structural lattice is arranged between the first portion and the second portion to impart energy absorption and stiffness to the containment case.

[0083] 13. The case apparatus of any preceding clause, wherein the structural lattice is a gyroid structure.

[0084] 14. The case apparatus of any preceding clause, wherein the protruding portion comprises an abradable layer between the structural lattice and an interior of the containment case.

[0085] 15. An apparatus comprising: a containment case of a turbofan engine; and a trench filler of the turbofan engine, the trench filler being located between the turbofan engine and the containment case, the trench filler comprising: a first layer comprising a solid metal; a second layer comprising at least one of a lattice structure, air, or a fluid, the first layer and the second layer surrounding at least a portion of the turbofan engine, the first layer and the second layer alternating in a radial direction.

[0086] 16. The apparatus of any preceding clause, wherein a first section of the trench filler comprises a first volume fraction to provide stiffness to the containment case.

[0087] 17. The apparatus of any preceding clause, wherein a second section of the trench filler comprises a second volume fraction to provide energy absorption, the second volume fraction being less than the first volume fraction.

[0088] 18. The apparatus of any preceding clause, wherein the first section of the trench filler is positioned within at least one of a front portion or a rear portion of the containment housing, and the second section of the trench filler is positioned within a middle portion of the containment housing between the front portion and the rear portion.

[0089] 19. The apparatus of any preceding clause, wherein the first section is positioned radially outward of the second section.

[0090] 20. The apparatus of any preceding clause, wherein the lattice structure is a gyroid icosahedron structure.

[0091] Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture falling within the scope of the claims.

[0092] The following claims are hereby incorporated into this detailed description by reference, each claim as a separate embodiment of this disclosure.

Claims

1. A housing apparatus, characterized by, Comprising: a first set of metal bands located within a containment housing of a turbofan engine; and a second set of metal bands traversing the first set of metal bands such that the first set of metal bands and the second set of metal bands form a truss and / or ribbed structure, the first set of metal bands and the second set of metal bands surrounding at least a portion of the turbofan engine, wherein the first set of metal bands and the second set of metal bands are disposed along a circumference within the containment housing, wherein the first set of metal bands are positioned concentrically around the second set of metal bands.

2. The case device according to claim 1, characterized by wherein, the first set of metal bands and the second set of metal bands comprise aluminum lithium.

3. The case device according to claim 1, characterized by, further comprising at least a third set of metal bands traversing or surrounding the first set of metal bands and the second set of metal bands.

4. The case device according to claim 1, characterized by wherein, the first set of metal bands and the second set of metal bands are integrated into the containment housing to provide at least one of stiffness or energy absorption.

5. The case device according to claim 1, characterized by, further comprising a deflector plate fixed to an outer surface of the containment housing.

6. A housing device, characterized by Comprising: a first portion of a containment housing of a turbofan engine; a second portion of the containment housing; and a protruding portion of the containment housing located between the first portion and the second portion, the protruding portion comprising a structural lattice.

7. The housing apparatus of claim 6, wherein, wherein, an inner portion of the structural lattice comprises a first volume fraction and an outer portion of the structural lattice comprises a second volume fraction, the first volume fraction being greater than the second volume fraction.

8. The case device according to claim 6, characterized by wherein, the protruding portion of the containment housing comprises a curvature in two geometric planes.

9. The case device according to claim 6, characterized by wherein, the protruding portion of the containment housing is aligned with fan blades of the turbofan engine.

10. The case device of claim 6, wherein, wherein, the structural lattice is arranged between the first portion and the second portion to impart energy absorption and stiffness to the containment housing.

11. The case device of claim 6, wherein, wherein, the structural lattice is a gyroid structure.

12. The case device of claim 6, wherein, wherein, the protruding portion comprises an abradable layer located between the structural lattice and an interior of the containment housing.

13. A housing apparatus, characterized by Comprising: a containment housing of a turbofan engine; and a trench filler of the turbofan engine located between the turbofan engine and the containment housing, the trench filler comprising: a first layer comprising a solid metal; and a second layer comprising at least one of a lattice structure, air, or a fluid, the first layer and the second layer surrounding at least a portion of the turbofan engine, the first layer and the second layer alternating in a radial direction.

14. The case device of claim 13, wherein, wherein, a first section of the trench filler comprises a first volume fraction to provide stiffness to the containment housing.

15. The case device of claim 14, wherein, wherein, a second section of the trench filler comprises a second volume fraction to provide energy absorption, the second volume fraction being less than the first volume fraction.

16. The case device of claim 15, wherein, wherein, The first section of the trench filler is positioned within at least one of a front portion or a rear portion of the containment housing, and the second section of the trench filler is positioned within a middle portion of the containment housing between the front portion and the rear portion.

17. The case device of claim 15, wherein, wherein, The first section is positioned outside of the second section in the radial direction.

18. The case device of claim 13, wherein, wherein, The lattice structure is a gyroid structure.

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