Turbine engine with compliant axial retainer

Abstract

A gas turbine engine includes a fan section, a compressor section, a combustion section, and a turbine section, the fan section, the compressor section, the combustion section, and the turbine section being in a serial flow arrangement and defining an engine centerline extending between a forward direction and an aft direction. The disc includes a slot for mounting the composite airfoil to the disc. An axial retainer is coupled to the disc and secures the composite airfoil to the disc. During operation of the gas turbine engine, a compliant portion positioned at the composite airfoil abuts the composite airfoil to secure the composite airfoil to the disk.

Description

Technical Field

[0001] The present disclosure relates generally to components of turbine engines and, more particularly, to a retainer for securing an airfoil to a disk. Background Art

[0002] A turbine engine typically includes an engine core having a compressor section, a combustor section, and a turbine section in a serial flow arrangement. The fan section may be disposed upstream of the compressor section. The compressor section compresses air that is directed to the combustor section, where the air is mixed with fuel and then the mixture is ignited in the combustor section to generate hot combustion gases. The combustion gases are directed to the turbine section, which extracts energy from the combustion gases for powering the compressor section and for generating useful work to propel an aircraft in flight or to power a load such as a generator.

[0003] Composite materials generally include a fiber-reinforced matrix and exhibit a high strength-to-weight ratio. Due to the high strength-to-weight ratio and formability into relatively complex shapes, composite materials are used in various applications, such as turbine engines or aircraft. For example, the composite material may be mounted on a fuselage and / or wing, rudder, manifold, airfoil, or other component of an aircraft or turbine engine, or define a portion thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0005] Figure 1 is a schematic cross-sectional view of a turbine engine according to an exemplary aspect of the present disclosure.

[0006] Figure 2 is suitable according to aspects of the present disclosure Figure 1 Schematic perspective view of a composite airfoil assembly and disk used within a turbine engine.

[0007] Figure 3 A composite airfoil having an axial retainer for securing the composite airfoil to a rotating disk according to an exemplary aspect of the present disclosure Figure 1 Schematic cross-sectional view of a portion of a turbine engine.

[0008] Figure 4 According to an exemplary aspect of the present disclosure Figure 3 A three-dimensional view of the axial retainer.

[0009] Figure 5 According to an exemplary aspect of the present disclosure Figure 4 The axial retainer is subject to Figure 3Schematic cross-sectional diagram of the forces acting on a composite airfoil.

[0010] Figure 6 is a schematic cross-sectional view of another exemplary axial retainer including a grid material according to an exemplary aspect of the present disclosure.

[0011] Figure 7 is a schematic cross-sectional view of another exemplary axial retainer including an expanded material according to an exemplary aspect of the present disclosure.

[0012] Figure 8 is a schematic cross-sectional view of another exemplary axial retainer including a perforated material according to an exemplary aspect of the present disclosure.

[0013] Fig. 9 is a schematic cross-sectional view of another exemplary axial retainer including a porous material according to exemplary aspects of the present disclosure.

[0014] Fig.10 is a schematic cross-sectional view of another exemplary axial retainer including a spring according to an exemplary aspect of the present disclosure.

[0015] Fig.11 is a schematic cross-sectional view of another exemplary axial retainer including an inlay structure according to an exemplary aspect of the present disclosure.

[0016] Fig.12 is a schematic cross-sectional view of another exemplary axial retainer including a capsule according to an exemplary aspect of the present disclosure.

[0017] Fig.13 is a schematic cross-sectional view of an alternative axial retainer including a reinforcement according to an exemplary aspect of the present disclosure.

[0018] Fig.14 is a flow chart illustrating a method of retaining a composite airfoil coupled to a disk using an axial retainer according to an exemplary aspect of the present disclosure. DETAILED DESCRIPTION

[0019] Aspects disclosed herein relate to an axial retainer for securing an airfoil to a disk. The airfoil may be slidably secured to the disk. The axial retainer secures the axial position of the airfoil relative to the disk to ensure that the airfoil does not fall off the disk. The airfoil may be a fan blade, a compressor blade, or a turbine blade. Although the present disclosure is provided as an airfoil axially secured to a disk, it should be understood that the present disclosure may be applied to non-airfoil attachments to a disk, such as utilizing a shroud or a combustor liner. Furthermore, although described in terms of a turbine engine for an aircraft, it should be understood that the present disclosure is applicable to any other suitable environment, including terrestrial and non-terrestrial applications, or environments utilizing a turbine engine requiring axial retention.

[0020] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter references to refer to features in the drawings. Like or similar reference numbers in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0021] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0022] As used herein, the terms “first” and “second” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0023] As used herein, the term "upstream" refers to the direction opposite to the direction of fluid flow, while the term "downstream" refers to the direction in the same direction as the direction of fluid flow. The terms "front" or "ahead" may mean in front of something, and "rear" or "rearward" may mean behind something, and may relate to the direction of flow of fluid through the engine. For example, when used in relation to fluid flow, front / front may mean upstream, and rear / rearward may mean downstream.

[0024] The term "fluid" may be gas or liquid, or multiple phases.

[0025] Furthermore, as used herein, the term "radial" or "radially" refers to directions away from a common center. For example, in the overall context of a turbine engine, radial refers to directions along a ray extending between a central longitudinal axis of the engine and an outer periphery of the engine.

[0026] All directional references (e.g., radial, axial, front, upstream, downstream, forward, backward, etc.) as may be used herein are used only for identification purposes to help the reader understand the present disclosure and do not create limitations, particularly limitations on the position, orientation, or use of the disclosed aspects described herein. Connection references (e.g., attachment, connection, connection) will be interpreted broadly and may include intermediate structural elements between sets of elements and relative movement between elements, unless otherwise indicated. Therefore, a connection reference does not necessarily mean that the two elements are directly connected and fixed relative to each other. The exemplary drawings are only for the purpose of illustration, and the dimensions, positions, orders, and relative sizes reflected in the attached drawings may vary.

[0027] Unless the context clearly dictates otherwise, the singular forms "a," "an," and "the" include plural references. Also, as used herein, the term "set" or a "set of" elements may be any number of elements, including only one.

[0028] As used herein, the term "stiffness" may be used to define the degree to which a structure resists deformation in response to a force. Stiffness may be defined as the ratio of the force to the displacement of an object under the action of a force. Stiffness may include resistance to deformation in response to forces applied from various directions, so that in non-limiting examples, stiffness may refer to axial stiffness, tensile stiffness, compressive stiffness, torsional stiffness, or shear stiffness.

[0029] As used herein, the term "elasticity" may be used to define the modulus of elasticity under tension or compression, and may relate to the elasticity of a particular material or structure made of such a material, such as an engine component as described herein. Elasticity may represent stress per unit area relative to local strain or its proportional deformation, or may be expressed as a bulk modulus, such as the ratio of force to deformation.

[0030] As used herein, the term "strength" may be used to qualify a value of a material or element, such as the maximum load or force that a material or element can withstand before the material deforms or fails. For example, "strength" may include tensile strength, compressive strength, shear strength, or torsional strength. Strength may be expressed or qualified, at least in part, as ultimate strength, plasticity, brittleness, yield strength, flexural strength, hardness, toughness, or resistance, such as electrical resistance, impact resistance, wear resistance, or corrosion resistance.

[0031] As used herein, the terms "compliance," "compliant," or "compliant" may be used to define a material or element that can deform, bend, move, or displace in response to a load or force. Such compliance may be related to the elasticity of the body upon which the force acts. For example, compliance may be inversely proportional to stiffness.

[0032] As used herein, the term "resistance" or "resistance force" may be used to define a force applied against a force acting on a particular element or object, a force resisting a force acting on a particular element or object, or a vector sum of forces in a direction opposite to a force acting on a particular element or object. For example, in additional non-limiting examples, "resistance" or "resistance force" may be a normal force applied by a particular element or object, or may be a friction force, a contact force, a drag force, or a viscous force, and may be defined by the stiffness, elasticity, or strength of a particular element or object.

[0033] As used herein, the term "composite" refers to a component having two or more materials. A composite can be a combination of at least two or more metals, non-metals, or a combination of metal and non-metal elements or materials. Examples of composite materials can be, but are not limited to, polymer matrix composites (PMC), ceramic matrix composites (CMC), metal matrix composites (MMC), carbon fibers, polymer resins, thermoplastic resins, bismaleimide (BMI) materials, polyimide materials, epoxy resins, glass fibers, and silicon matrix materials.

[0034] As used herein, a "composite" component refers to a structure or component that includes any suitable composite material. A composite component, such as a composite airfoil, may include several layers or several layups of composite materials. The stiffness, material, and dimensions of the layers or layups may vary to achieve a desired composite component or composite portion of a component having a predetermined weight, size, stiffness, and strength.

[0035] One or more layers of adhesive may be used to form or join the composite parts. The adhesive may include resins and phenolics, where the adhesive may be cured at elevated temperatures or other hardening techniques.

[0036] As used herein, PMC refers to a class of materials. As an example, PMC materials are partially defined by prepregs, which are reinforcing materials pre-impregnated with polymer matrix materials (e.g., thermoplastic resins). Non-limiting examples of processes for producing thermoplastic prepregs include: hot melt prepregs, in which fiber reinforcements are pulled through a molten bath of resin; and powder prepregs, in which resin is deposited on the fiber reinforcements, as a non-limiting example, electrostatically deposited on the fiber reinforcements, and then adhered to the fibers, as a non-limiting example, in an oven or with the help of heated rollers. Prepregs can be in the form of unidirectional tapes or woven fabrics, which are then stacked on top of each other to form the desired number of stacked layers of a part.

[0037] Multilayer prepreg is stacked to the appropriate thickness and orientation of composite parts, and then resin is cured and solidified to provide fiber reinforced composite parts. The resin for PMC matrix material can be generally classified as thermosetting resin or thermoplastic resin. Thermoplastic resin is generally classified as a polymer that can be repeatedly softened and flowed when heated and can be hardened due to physical changes rather than chemical changes when fully cooled. The famous example category of thermoplastic resin includes nylon, thermoplastic polyester, polyaryletherketone and polycarbonate resin. The specific example of high-performance thermoplastic resin for aerospace applications has been envisioned to include polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyaryletherketone (PAEK) and polyphenylene sulfide (PPS). On the contrary, once fully cured into a hard rigid solid, thermosetting resin will not experience significant softening when heated, but thermally decomposes when fully heated. The famous example of thermosetting resin includes epoxy resin, bismaleimide (BMI) and polyimide resin.

[0038] Instead of using prepreg, in another non-limiting example, by using thermoplastic polymers, woven fabrics can be utilized. Woven fabrics may include, but are not limited to, dry carbon fibers woven together with thermoplastic polymer fibers or filaments. Non-prepreg weaving architectures can be made in a similar manner. With this approach, the fiber volume of a part can be customized by specifying the relative concentrations of thermoplastic fibers and reinforcing fibers that have been woven or woven together. In addition, different types of reinforcing fibers can be woven or woven together at different concentrations to customize the properties of a part. For example, glass fibers, carbon fibers, and thermoplastic fibers can be woven together at different concentrations to customize the properties of a part. Carbon fibers provide the strength of the system, glass fibers can be incorporated to enhance impact properties, which is a design feature of a part located near the engine inlet, and thermoplastic fibers provide bonding for the reinforcing fibers.

[0039] In yet another non-limiting example, resin transfer molding (RTM) can be used to form at least a portion of a composite component. Typically, RTM includes applying a dry fiber or matrix material to a mold or cavity. The dry fiber or matrix material may include prepreg, braided material, woven material, or any combination thereof.

[0040] The resin may be pumped or otherwise provided to the mold or cavity to impregnate the dry fibers or matrix material. The combination of the impregnated fibers or matrix material and the resin is then cured and removed from the mold. When removed from the mold, the composite part may be handled after curing.

[0041] It is contemplated that RTM may be a vacuum assisted process. That is, the air in the cavity or mold may be removed and replaced with resin prior to heating or curing. It is further contemplated that placement of the dry fiber or matrix material may be manual or automated.

[0042] The dry fiber or matrix material may be shaped to form the composite part or to guide the resin. Optionally, additional layers or reinforcements of a material different from the dry fiber or matrix material may also be included or added prior to heating or curing.

[0043] As used herein, CMC refers to a class of materials having reinforcing fibers in a ceramic matrix. Typically, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of reinforcing fibers may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates (such as mullite), or mixtures thereof), or mixtures thereof.

[0044] Some examples of ceramic matrix materials may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, or mixtures thereof), or mixtures thereof. Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite) may also be included in the ceramic matrix.

[0045] In general, specific CMCs can be referred to as their fiber type / matrix type combination. For example, C / SiC is carbon fiber reinforced silicon carbide, SiC / SiC is silicon carbide fiber reinforced silicon carbide, SiC / SiN is silicon carbide fiber reinforced silicon nitride, SiC / SiC-SiN is silicon carbide fiber-reinforced silicon carbide / silicon nitride matrix mixture, etc. In other examples, CMCs can be composed of a matrix and reinforcing fibers comprising oxide-based materials such as aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, and mixtures thereof. Aluminosilicates can include crystalline materials such as mullite (3Al2O3·2SiO2), as well as glassy aluminosilicates.

[0046] In certain non-limiting examples, the reinforcing fibers may be bundled, coated, or both before being included in the ceramic matrix. For example, the fiber bundles may be formed into reinforcing tapes, such as unidirectional reinforcing tapes. Multiple tapes may be stacked together to form a preform component. The fiber bundles may be impregnated with a slurry composition before or after forming the preform. The preform may then be subjected to heat treatment and subsequent chemical treatment to obtain a component formed of a CMC material having a desired chemical composition. For example, the preform may undergo curing or burnout to produce a high coke residue in the preform, and then melt infiltrated with silicon, or undergo curing or pyrolysis to produce a silicon carbide matrix in the preform, and then chemical vapor infiltration with silicon carbide. Additional steps may be taken to improve the densification of the preform, by injecting the preform with a liquid resin or polymer before or after chemical vapor infiltration, and then performing a heat treatment step to fill the voids with silicon carbide. CMC materials as used herein may be formed using any known or later developed method including, but not limited to, melt infiltration, chemical vapor infiltration, polymer infiltration pyrolysis (PIP), or any combination thereof.

[0047] Such materials, along with certain monolithic ceramics (i.e., ceramic materials without reinforcement materials), are particularly useful for higher temperature applications. In addition, these ceramic materials are lightweight compared to superalloys, yet still provide strength and durability to components made therefrom. As a result, such materials are currently being considered for use in many gas turbine components used in the higher temperature sections of gas turbine engines (such as airfoils (e.g., turbines and buckets), combustors, shrouds, and other components) that would benefit from the lighter weight and higher temperature capabilities that these materials can provide.

[0048] The term "metal" as used herein refers to a material including metals such as, but not limited to, titanium, iron, aluminum, stainless steel, and nickel alloys. A metal material or alloy may be a combination of at least two or more elements or materials, at least one of which is a metal. A "non-metal" material as used herein refers to a material that does not include a metal, or a material that is formed as a mixture of a metal and a non-metal material.

[0049] The inventors practiced in the manner described above (i.e., designing a retention system as an axial retainer for securing an airfoil to a disk; and designing an axial retainer to have improved compliance to extreme loads when using a composite airfoil or axial retention for a compliant component). Conventional retention systems may utilize materials that compress under axial loads. However, after compressing, these retention systems are unable to return to their original shape or position, and particularly fail to provide compliant retention over time.

[0050] Figure 1is a schematic cross-sectional view of a turbine engine 10 for an aircraft. The turbine engine 10 has a generally longitudinally extending axis or engine centerline 12 extending from a forward direction 14 to an aft direction 16. The turbine engine 10 includes, in downstream serial flow relationship: a fan section 18 including a fan 20; a compressor section 22 including a supercharger or low pressure (LP) compressor 24 and a high pressure (HP) compressor 26; a combustion section 28 including a combustor 30; a turbine section 32 including an HP turbine 34 and an LP turbine 36; and an exhaust section 38.

[0051] The fan section 18 includes a fan case 40 surrounding the fan 20. The fan 20 includes a plurality of fan blades 42 radially arranged around the engine centerline 12. The HP compressor 26, the combustor 30, and the HP turbine 34 form an engine core 44 of the turbine engine 10, which generates combustion gases. The engine core 44 is surrounded by a core case 46, which may be coupled to the fan case 40.

[0052] An HP shaft or spool 48 disposed coaxially about the engine centerline 12 of the turbine engine 10 drivingly connects the HP turbine 34 to the HP compressor 26. An LP shaft or spool 50 disposed coaxially about the engine centerline 12 of the turbine engine 10 within the larger diameter annular HP spool 48 drivingly connects the LP turbine 36 to the LP compressor 24 and the fan 20. The HP spool 48 and the LP spool 50 are rotatable about the engine centerline 12 and are coupled to a plurality of rotatable elements that may collectively define a rotor 51.

[0053] The LP compressor 24 and the HP compressor 26 each include a plurality of compressor stages 52, 54, wherein a set of compressor blades 56, 58 rotate relative to a corresponding set of static compressor vanes 60, 62 to compress or pressurize a fluid flow through the stage. In a single compressor stage 52, 54, the plurality of compressor blades 56, 58 may be arranged in a ring and may extend radially outward from a blade platform to a blade tip relative to the engine centerline 12, with the corresponding static compressor vanes 60, 62 positioned upstream and adjacent to the rotating compressor blades 56, 58. Notably, Figure 1 The numbers of blades, buckets, and compressor stages shown in FIG. 5 are selected for illustration purposes only, and other numbers are possible.

[0054] Compressor blades 56, 58 for a stage of the LP compressor 24 or HP compressor 26 may be mounted to (or integrated into) a disk 61 mounted to a corresponding one of the HP and LP spools 48, 50. Static compressor vanes 60, 62 for a stage of the compressor may be mounted to the core housing 46 in a circumferential arrangement.

[0055] The HP turbine 34 and the LP turbine 36 each include a plurality of turbine stages 64, 66, wherein a set of turbine blades 68, 70 rotate relative to a corresponding set of static turbine vanes 72, 74 (also referred to as nozzles) to extract energy from a fluid flow passing through the stage. In a single turbine stage 64, 66, the plurality of turbine blades 68, 70 may be arranged in a ring and may extend radially outward relative to the engine centerline 12, while the corresponding static turbine vanes 72, 74 are positioned upstream and adjacent to the rotating turbine blades 68, 70. Notably, Figure 1 The number of blades, buckets, and turbine stages shown in FIG. 5 are selected for illustrative purposes only, and other numbers are possible.

[0056] Turbine blades 68, 70 for a stage of the HP turbine 34 or LP turbine 36 may be mounted to a disk 71 mounted to a corresponding one of the HP and LP spools 48, 50. Static turbine buckets 72, 74 for a stage of the LP compressor 24 or HP compressor 26 may be mounted to the core housing 46 in a circumferential arrangement.

[0057] Complementing the rotor portion, the stationary portion of the turbine engine 10, such as the static compressor or turbine buckets 60, 62, 72, 74 in the compressor section 22 and the turbine section 32, are also individually or collectively referred to as stators 63. Thus, the stator 63 may refer to the combination of non-rotating elements throughout the turbine engine 10.

[0058] In operation, the airflow exiting the fan section 18 is split so that a portion of the airflow is directed into the LP compressor 24, which then supplies the pressurized airflow 76 to the HP compressor 26, which further pressurizes the air. The pressurized airflow 76 from the HP compressor 26 is mixed with the fuel in the combustor 30 and ignited, thereby generating combustion gases. The HP turbine 34 extracts some work from these gases, which drives the HP compressor 26. The combustion gases are exhausted into the LP turbine 36, which extracts additional work to drive the LP compressor 24, and the exhaust gas is ultimately exhausted from the turbine engine 10 via the exhaust section 38. The drive of the LP turbine 36 drives the LP spool 50 to rotate the fan 20 and the LP compressor 24.

[0059] A portion of the pressurized air flow 76 may be extracted from the compressor section 22 as bleed air 77. The bleed air 77 may be extracted from the pressurized air flow 76 and provided to engine components for cooling. The temperature of the pressurized air flow 76 entering the combustor 30 is significantly increased to above the bleed air temperature. The bleed air 77 may be used to reduce the temperature of core components downstream of the combustor 30.

[0060] The remaining portion of the pressurized airflow 76 bypasses the LP compressor 24 and the engine core 44 as a bypass airflow 78 and exits the turbine engine 10 through a stationary vane row at the fan exhaust side 84, and more specifically, exits the turbine engine 10 through an exit guide vane assembly 80 (including a plurality of airfoil guide vanes 82) at the fan exhaust side 84. More specifically, a circumferential row of radially extending airfoil guide vanes 82 are used adjacent the fan section 18 to exert some directional control on the airflow 78.

[0061] Some of the air supplied by the fan 20 may bypass the engine core 44 and be used to cool portions of the turbine engine 10, particularly the hot portions, and / or to cool or power other aspects of the aircraft. In the case of a turbine engine, the hot portions of the engine are typically downstream of the combustor 30, particularly the turbine section 32, with the HP turbine 34 being the hottest portion as it is located directly downstream of the combustion section 28. Other sources of cooling fluid may be, but are not limited to, fluid discharged from the LP compressor 24 or the HP compressor 26.

[0062] Figure 2 Is suitable for Figure 1 1 is a schematic perspective view of a composite airfoil 100 and a disk 102 for use within a turbine engine 10 of FIG. Composite airfoil 100 may define a body 104. Disk 102 is suitable for use as disks 61, 71 ( Figure 1 ) or any other disk, such as but not limited to turbine engine 10 ( Figure 1 ) of fan section 18 ( Figure 1 )、Compressor section 22( Figure 1 ) or turbine section 32 ( Figure 1 ) within the disk. The composite airfoil 100 may be rotating or non-rotating, such that the composite airfoil 100 may include static compressor blades 60, 62 ( Figure 1 ), the set of compressor blades 56, 58 ( Figure 1 ), static turbine blades 72, 74 ( Figure 1 ), the group of turbine blades 68, 70 ( Figure 1 ) or a plurality of fan blades 42 ( Figure 1 ). As a non-limiting example, the composite airfoil 100 may be a composite fan blade.

[0063] The disk 102 may rotate or be stationary about an axis of rotation 106. The axis of rotation 106 may be aligned with the engine centerline 12 ( Figure 1 ) coincident, parallel, or offset. The disk 102 includes a plurality of slots 108 extending axially through a radially outer surface 112 of the disk 102. The plurality of slots 108 are circumferentially spaced about the disk 102 relative to the axis of rotation 106 and allow the composite airfoil 100 to be slidably secured to the disk 102.

[0064] The composite airfoil 100 and its body 104 extend between a leading edge 114 and a trailing edge 116 to define a chord-wise direction, and between a root 118 and a tip 120 to define a span-wise direction. The composite airfoil 100 includes a pressure side 122 and a suction side 124.

[0065] The composite airfoil 100 is coupled to the disk 102 by inserting at least a portion of the composite airfoil 100 into a corresponding slot in the plurality of slots 108. The composite airfoil 100 is held in place by frictional contact with the slot 108, or may be coupled to the slot 108 via any suitable coupling method, such as, but not limited to, welding, bonding, fastening, etc. Although only a single composite airfoil 100 is shown, it should be understood that there may be any number of one or more composite airfoils 100 coupled to the disk 102. As a non-limiting example, there may be a number of composite airfoils 100 corresponding to the total number of slots in the plurality of slots 108.

[0066] For ease of reference, a set of relative reference directions and coordinate systems may be applied to the composite airfoil 100 and the disk 102. The axial direction (Ad) may extend from front to back and is shown as extending at least partially into the page. The axial direction (Ad) may be arranged parallel to the rotation axis 106, which may also be arranged parallel to the engine centerline 12 ( Figure 1 The radial direction (Rd) extends perpendicular to the axial direction (Ad), and the radial direction (Rd) may extend perpendicular to the engine centerline 12. The circumferential direction (Cd) may be defined as being perpendicular to the radial direction (Rd), and the circumferential direction (Cd) may be defined as being along a curvature of a circle about the axial direction (Ad), may be defined as a ray extending locally from the radial direction (Rd), and / or may be defined as being relative to the engine centerline 12 ( Figure 1 ) or the axis of rotation 106 along the turbine engine 10 ( Figure 1 )’s circumference.

[0067] Figure 3 is a schematic cross-sectional view of a portion of turbine section 32 and illustrates composite airfoil 100 coupled to disk 102 via axial retainers 130 that secure composite airfoil 100 to disk 102. Figure 3 As shown, the circumferential direction (Cd) may be defined as being perpendicular to the radial direction (Rd), represented by an “X” extending into and out of the page, and may be defined as being circumferential relative to the axis of rotation 106 .

[0068] For example, the composite airfoil 100 may be more compliant than a metal airfoil and may include higher compliance in the surrounding retention system (e.g., the disk 102 and the axial retainer 130). During engine operation, the axial retainer 130 allows compliant movement of the composite airfoil 100 in the axial direction Ad. The axial retainer 130 reduces the resistance experienced by the composite airfoil 100 from the axial retainer 30 during engine load, which can reduce stress on the composite airfoil 100, thereby reducing cyclic fatigue and extending component life. The reduction in resistance is achieved by the compliance of the axial retainer 130, which deforms at least partially in response to the load force applied against the axial retainer, and then at least partially recovers to its original shape after the engine load is reduced or stopped.

[0069] During engine operation, the composite airfoil 100 is subject to engine forces and load forces, which may include forces tending to move or bend the composite airfoil 100 in the forward direction 14 or the aft direction 16, or in a direction that would disengage or decouple the composite airfoil 100 from the disk 102. Depending on the particular engine implementation, the axial retainer 130 may be positioned forward or aft of the composite airfoil 100 and retain the composite airfoil 100 within the slot 108 under such engine forces.

[0070] Figure 4 1 shows a perspective view of an axial retainer 130 including a body 132 coupled to a compliant portion 134. The body 132 includes a receiver 136 adapted to receive a fastener (not shown) such as a bolt or threaded fastener to secure the axial retainer 130 to the disk 102 ( Figure 3 ). Although only one receiver 136 is shown, any number or suitable type of attachment or mounting systems are contemplated for securing the axial retainer 130 to the disk 102. The body 132 may be metallic, such as made of one or more metals such as nickel, tungsten, or titanium in a non-limiting example, or a composite metal including a composite material of more than one metallic material. The body 132 may define a first bulk modulus defined by the material comprising the body 132. In a non-limiting example, the bulk modulus may be equal to or greater than the bulk modulus of the disk 102.

[0071] The compliant portion 134 may be a compliant or elastic element that may be compressed or otherwise deformed in response to a load force (such as force 138 described herein) against the axial retainer 130, and then fully or at least partially recover to its original shape after the load force ceases. For example, after the load force ceases, it is contemplated that the compliant portion 134 recovers completely to its non-deformed shape, or in alternative non-limiting examples, such as when an excess force unexpected from operational expectations acts thereon, the compliant portion may recover to at least 90% of the non-deformed shape or at least 80% of the non-deformed shape. In a non-limiting example, the compliant portion 134 may be non-metallic, or a mixture of metallic and non-metallic materials. In another non-limiting example, the compliant portion 134 defines a second bulk modulus defined by the material or structure of the compliant portion 134. In a non-limiting example, the second bulk modulus may be less than the first bulk modulus of the body 132. Suitable materials that may be used for the compliant portion 134 include, but are not limited to, rubber, polyurethane, urethane, or foam. Additionally or alternatively, the compliant portion 134 may define a lower yield strength than the body 132. In a non-limiting example, the yield strength may be 50% of that of the body 132.

[0072] refer to Figure 5 During engine operation, a force 138 may be applied from the adjacent composite airfoil 100 to the axial retainer 130. The axial retainer 130 secures the position of the composite airfoil 100 to prevent the composite airfoil 100 from being displaced from the disk 102 ( Figure 3 ) is separated. The compliant portion 134 can be deformed from the non-deformed shape 140 to the deformed shape 142. The deformed shape 142 is represented via dashed lines relative to the non-deformed shape 140. The compliant portion 134 is deformed from the non-deformed shape 140 to the deformed shape 142 in response to the force 138. After the force 138 ceases, the compliant portion 134 can fully or at least partially return to its non-deformed shape 140.

[0073] During engine operation, engine forces may move or push the composite airfoil 100 toward the axial retainer 130, thereby defining a force 138 acting on the axial retainer 130. The compliant portion 134 of the axial retainer 130 deforms in response to the force 138, thereby providing compliance to the composite airfoil 100. The compliance of the composite airfoil 100 may reduce stress and strain on the composite airfoil 100 to improve durability and compliance when operating under high engine load conditions. The axial retainer 130 provides this compliance through the compliant portion 134, thereby allowing deformation in response to the force 138 and returning to its original position after the force 138 ceases.

[0074] In addition, the axial retainer 130 with the compliant portion 134 allows the composite airfoil 100 to contact the axial retainer 30 with reduced resistance. This reduced resistance is provided by the compliance of the compliant portion 134, which generates reduced resistance compared to an axial retainer without a compliant portion. The compliant portion 134 also allows the compliance to be customized according to the system in which the compliant portion 134 is incorporated, wherein the material or geometry used for the compliant portion 134 can be varied to customize the compliance characteristics according to a specific system or expected load conditions (such as the load conditions of a turbine blade).

[0075] refer to Figure 6 , a schematic cross-sectional view of another exemplary axial retainer 150 includes a body 152 and a compliant portion 154. The compliant portion 154 may be a grid material 156, shown as having a grid structure. Alternative grid structures in non-limiting examples include an inclined structure, a square structure, a hexagonal structure, a triangular structure, a rectangular structure, a triclinic structure, a monoclinic structure, an orthogonal structure, a quadrilateral structure, a cubic structure, a triangular structure, or a combination thereof. The grid material 156 for the compliant portion 154 may define one or more open areas, gaps, or spaces 158 that allow compression when subjected to a force 160 and then at least partially recover to an original shape after the force 160 ceases. The space 158 may be empty, open-cell, or may be filled with a substance, such as including engine gases that are allowed to pass through the space 158 during engine operation. In another non-limiting example, the space 158 may be permanently filled, such as with a pressurized gas. Alternatively or additionally, it is contemplated that spaces 158 may be filled with a compliant material that may be used to control deformation of compliant portion 154. Such compliant material may be different than the compliant material of compliant portion 154, although similar materials of different densities or having other different properties are contemplated. In conjunction with the material used as grid material 156 or disposed within spaces 158, the geometry of grid material 156 and its spaces 158 (or the material disposed therein) allows compliant portion 154 to deform when subjected to force 160 and then return to its original shape after force 160 ceases. In a non-limiting example, grid material 156 or material filling spaces 158 may expand in a direction orthogonal to the direction of compression. Suitable materials for compliant portion 154 or filling spaces 158 may include, but are not limited to, rubber, polyurethane, or other polymers.

[0076] The specific grid geometry and material used may be used to define material density, elasticity, stiffness, strength, or other material properties, which allows for adjustment of the compliance of compliant portion 154 to expected loads. For example, the thickness of the various walls of grid material 156 and the size or volume of space 158 therebetween may at least partially define the compliance, which may be used to define the amount of compression allowed by compliant portion 154. Similarly, space 158 may provide overall weight reduction, which may benefit overall engine efficiency when filled with gas or filled with a compliant material of less mass or density than the compliant material used for grid material 156.

[0077] Figure 7 A schematic cross-sectional view of another axial retainer 200 including a body 202 and a compliant portion 204 is shown. The compliant portion 204 may include an expansion material 206. In one example, the expansion material 206 may be a material defined by a negative Poisson's ratio. The expansion material 206 may be a material that contracts in a contraction direction 208 that is orthogonal to the compression direction of the force 210. Due to the contraction under compression, the material density of the compliant portion 204 increases under compression. Therefore, as the force 210 is increasingly applied to the compliant portion 204, the density of the compliant portion 204 increases, resulting in an increase in compliance response with increasing compression. That is, the resistance applied in response to the force 210 increases as the force 210 increases. The resulting response to the force 210 is non-linear, providing an increased compliance or an increased compliance rate as the force 210 increases.

[0078] Figure 8 A schematic cross-sectional view of another axial retainer 250 is shown that includes a body 252 and a compliant portion 254. The compliant portion 254 includes at least one opening 256, shown as a set of elongated apertures 258 extending through the compliant portion 254. The set of elongated apertures 258 defining the compliant portion 254 allows the compliant portion 254 to be compressed in response to a force 260 and at least partially return to its original position after the force 260 ceases.

[0079] Although shown as a set of nine elongated orifices 258, it should be understood that any number, arrangement or positioning of at least one opening 256 is contemplated. In addition, although the set of elongated orifices 258 extends in a direction orthogonal to the direction of the force 260, any suitable arrangement of the set of elongated orifices 258 is contemplated, including but not limited to being aligned with, orthogonal to, or angled relative to the direction of the force 260. In addition, although shown as a set of elongated orifices 258, the at least one opening 256 may include any suitable shape or cross-section thereof, including but not limited to circular, oval, elliptical, racetrack, square, rectangular, cubic, linear, curvilinear, unique, or any combination thereof. The specific arrangement and geometry of the at least one opening 256 can be used to define the compliance provided by the compliant portion 254. For example, the location, arrangement or geometry of the at least one opening 256 can be used to locally increase or decrease the compliance response. Such local customization can be used to customize the compliance response of the component or material providing the force 260, such as with the engine centerline 12 ( Figure 1 ) increases with increasing radial distance.

[0080] refer to Fig. 9 , a schematic cross-sectional view shows an axial retainer 300 including a body 302 and a compliant portion 304, the compliant portion 304 being configured as a porous material 306 having a plurality of pores 308. In a non-limiting example, the porous material 306 can be a closed-cell foam or an open-cell porous foam. For example, where the porous material 306 is a closed-cell foam, the closed cells can be filled with a gas, such as carbon dioxide (CO2). For example, such a gas can be maintained at a pressure varying between 2 pounds per square inch absolute and 100 pounds per square inch absolute (2PSIA-100PSIA), with pressures above ground-level atmospheric pressure being contemplated. Such a porous material 306 can be a material that compresses in response to a force 310, and then decompresses after the force 310 ceases, at least partially returning to its original shape.

[0081] refer to Fig.10 , a schematic cross-sectional view shows an axial retainer 350 including a body 352 and a compliant portion 354. The compliant portion 354 can be formed as a set of springs 356. In one non-limiting example, the set of springs 356 can be formed as a set of Belleville washers 358, which can be arranged in an aligned, nested or parallel arrangement 360, an offset or series arrangement 362, or an arrangement 364 that is a combination thereof. In another non-limiting example, the set of springs 356 can include a set of wave springs 366. The set of springs 356 allows the compliant portion 354 to be compressed in response to a force 368, and then decompress after the force 368 ceases, at least partially returning to its original shape and position.

[0082] Additional non-limiting examples of the set of springs 356 may include, but are not limited to, spring fingers, leaf springs, coil springs, lock washers, or split ring washers that may be arranged in a nested arrangement or an offset arrangement, or a combination thereof. In another non-limiting example, the springs may be formed as a spring array (such as a cylindrical array), while any suitable element that provides a spring force may be utilized.

[0083] Additionally, while the set of springs 356 is arranged to compress in one direction in response to force 368 (such as aligned with force 368), it is contemplated that the springs may be arranged to resist force 368 in various directions. For example, force 368 may extend in an axial direction (Ad) as shown, or may be different from the axial direction (Ad), such as extending in a radial direction (Rd) or a circumferential direction (Cd), or in any combination of two or more directions.

[0084] refer to Fig.11 , a schematic cross-sectional view shows an axial retainer 400 including a body 402 and a compliant portion 404. The compliant portion 404 may include a mosaic structure 406. The mosaic structure 406 may be an arrangement of a group of individual geometric units 408 that are interconnected or folded to form the mosaic structure 406. The shapes and geometries of the individual geometric units 408 define an interconnection system to form an interconnected mosaic structure 406. In addition, the specific geometry or materials used for the individual geometric units may define the directionality of compression and the resistance. When subjected to a force 410, the folded, interconnected structure of the mosaic structure 406 allows compression and then can be at least partially restored to its original non-compressed state after the force 410 stops, which can be defined by the geometry and interconnected structure of the mosaic structure 406. That is, no additional force is required to fully or partially restore the mosaic structure 406 to its original non-compressed state.

[0085] refer to Fig.12 , a schematic cross-sectional view shows an axial retainer 450 including a body 452 and a compliant portion 454. The compliant portion 454 may include a capsule 456, which includes a capsule wall 464 contained within an outer wall 458 of the compliant portion 454. The capsule 456 can be made of a flexible or compliant material (such as rubber or a polymer) that can deform but not leak. The capsule 456 defines an interior 460, which can be filled with, for example, a gas or supercritical fluid that can be pressurized. For example, the interior 460 can be filled with pressurized CO2.

[0086] In operation, force 462 is applied to compliant portion 454 and bladder 456 may compress along with outer wall 458, thereby providing compliance in response to force 462. The particular pressure or material used to fill bladder 456 may define the resistive force provided by axial retainer 450.

[0087] refer to Fig.13 , a schematic cross-sectional view shows an axial retainer 500 including a body 502 and a compliant portion 504. The compliant portion 504 includes a compliant material 506 having at least one reinforcement 508. The at least one reinforcement 508 can be metallic and can be made of a material similar to that of the body 502. The at least one reinforcement 508 can extend completely through the compliant portion 504, or can extend partially or be discretely positioned within the compliant portion 504.

[0088] In operation, compliant material 506 may compress in response to force 510. At least one stiffener 508 resists such compression, such as by having a greater stiffness or less compliance relative to compliant material 506, and may limit or otherwise constrain the amount, distance, or directionality of compression of compliant material 506. More specifically, when force 510 deforms compliant material 506, at least one stiffener 508 does not deform, or deforms less than the deformation of compliant material 506. In this manner, the amount of deformation or directionality of deformation may be limited or otherwise defined by the use of at least one stiffener 508.

[0089] Reference now Fig.14 , schematic diagram illustrating a method 600 for retaining a composite airfoil coupled to a disk using an axial retainer. In a non-limiting example, the composite airfoil may be as described herein Figure 2 , Figure 3 and Figure 5 The composite airfoil 100, the disk may be as described herein Figure 1 and Figure 2 The disks 71, 102, and the axial retainer may be Figure 4-13 Axial retainers 130 , 150 , 200 , 250 , 300 , 350 , 400 , 450 , 500 .

[0090] The method 600 may include, at 602, deforming a compliant portion of an axial retainer from a non-deformed shape to a deformed shape, such as Figure 5 The non-deformed shape 140 and the deformed shape 142. For example, as described herein, the compliant portion may be Figure 4-13 The compliant parts 134, 154, 204, 254, 304, 354, 404, 454, 504.

[0091] In one example, deformation of the compliant portion may include deformation of the compliant portion in response to a force such as Figure 4-12The non-deformed shape may include a compliant portion in an uncompressed state, and the deformed shape may include a compliant portion in a compressed state. The compliant portion may be made of a compliant material such as a rubber, polyurethane, or urethane that compresses in response to a force, such as Figure 5 In a non-limiting example, the compliant portion may include Figure 6 The grill material is 156, Figure 7 The expansion material 206, Figure 8 at least one opening 256, Fig. 9 The porous material 306, Fig.10 Springs 356, 366, Fig.11 The mosaic structure 406, Fig.12 of Sac 456, Fig.13 The compliant material 506 or a combination thereof, in a non-limiting example, each of which can be compressed in response to a force.

[0092] At 604, method 600 may include resisting the force with a compliant portion that provides the resistance. While the compliant portion is allowed to compress to deform, the compliant portion may resist such deformation in many ways. Resisting deformation provides customization of compliance to a particular system or implementation. For example, the load forces experienced by a composite airfoil as a rotating fan blade are different from the load forces experienced by a rotating high pressure turbine blade. Therefore, it is within the scope of the present disclosure to customize the compliance of the axial retainer to suit its implementation, which can be achieved by limiting the resistance provided by the compliant portion. For example, specific material properties may be used to limit the resistance because a material with a larger bulk modulus is more resistant to deformation than a material with a relatively smaller bulk modulus. Additionally, structural properties may be used to limit the resistance. For example, the resistance may be changed by changing one or more of the following: Figure 6 The wall of the grid material 156 or Figure 7 The thickness of the expansion material 206; Figure 6 The pressure in the space 158; Figure 8 the size or location of at least one opening 256; Fig. 9 the density of the porous material 306; whether any pores or openings are closed or open; Fig.10 the arrangement or type of springs 356, 366; Fig.11 The geometry of the mosaic structure 406; Fig.12 The size or filling material of the bladder 456 may be used to change the resistance provided by the compliant portion. Fig.13 The arrangement or thickness of at least one reinforcement member 508.

[0093] In such cases, by reducing the turbine engine 10 ( Figure 1 ), after the cyclic rate of the compression force is reduced or the force is stopped, at 606, the method 600 may include restoring the compliant portion from the deformed shape to the non-deformed shape. Material properties, such as material type, structure, or geometry, allow the compliant portion to at least partially or completely return to the non-deformed position. For example, a rubber material will return to its original shape after compression as long as the rubber material is not stretched beyond its elastic limit. Similarly, the shape, geometry, or size of the grid material 156, the expansion material 206, the at least one opening 256, the porous material 306, the bladder 456, and the spring force of the springs 356, 366, the arrangement and design of the inlay structure 406, or the material or pressure within the at least one opening 256, the porous material 306, or the bladder 456, or any other suitable property or feature, may be utilized to restore the compliant portion to the non-deformed shape.

[0094] The benefits associated with using a compliant portion for an axial retainer provide improved compliance for a component that applies forces to the axial retainer. Composite airfoil designs can benefit from a greater amount of compliance than conventional metal airfoils, and the axial retainer can provide at least some compliance that is beneficial to the composite airfoil. The specific material, geometry, pattern, thickness, pressure, or other mechanical features used in the compliant portion can define the deformed shape and amount of deformation in response to a load force and allow the compliant portion to return to a non-deformed shape. This allows continued use of an axial retainer where only the deformed retainer must be replaced after each single use resulting in deformation.

[0095] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined method. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

[0096] Further aspects are provided by the subject matter of the following clauses:

[0097] 1. A gas turbine engine, comprising:

[0098] a fan section, a compressor section, a combustion section, and a turbine section, the fan section, the compressor section, the combustion section, and the turbine section being in a serial flow arrangement and defining an engine centerline extending between a forward direction and an aft direction;

[0099] a disk disposed in one of the fan section, the compressor section, or the turbine section and comprising a slot;

[0100] a composite airfoil coupled to the disk at the slot; and

[0101] An axial retainer is coupled to the disk and secures the composite airfoil within the slot, the axial retainer including a compliant portion positioned adjacent the composite airfoil.

[0102] A gas turbine engine according to any preceding clause, wherein the compliant portion is capable of deforming from a non-deformed shape to a deformed shape in response to a force from the composite airfoil acting on the axial retainer, and wherein the compliant portion at least partially recovers to its non-deformed shape after the force ceases.

[0103] A gas turbine engine as claimed in any preceding clause, wherein said compliant portion fully returns to said non-deformed shape after cessation of said force.

[0104] A gas turbine engine according to any preceding clause, wherein the compliant portion expands in a direction orthogonal to the force.

[0105] A gas turbine engine according to any preceding clause, wherein the compliant portion is made of rubber, polyurethane, urethane or a polymer.

[0106] A gas turbine engine according to any preceding clause, wherein the compliant portion is arranged forwardly of the composite airfoil.

[0107] A gas turbine engine as described in any preceding clause, wherein the axial retainer comprises a body and the compliant portion coupled to the body.

[0108] A gas turbine engine as described in any preceding clause, wherein the body is metallic and defines a first bulk modulus.

[0109] A gas turbine engine as described in any preceding clause, wherein the compliant portion defines a second bulk modulus that is less than the first bulk modulus.

[0110] A gas turbine engine as described in any preceding clause, wherein the body defines a first yield strength and the compliant portion defines a second yield strength that is less than the first yield strength.

[0111] A gas turbine engine having a fan section, a compressor section, a combustion section and a turbine section, the fan section, the compressor section, the combustion section and the turbine section being in a serial flow arrangement and arranged as a rotor and a stator so that the rotor rotates about an engine centerline, the gas turbine engine comprising:

[0112] Composite parts; and

[0113] An axial retainer for fixing the composite component to one of the rotor or the stator, the axial retainer having a non-deformed shape and a deformed shape, wherein the deformed shape is defined in response to a force acting on the axial retainer from the composite component.

[0114] A gas turbine engine according to any preceding clause, wherein the composite component is a composite airfoil.

[0115] A gas turbine engine according to any preceding clause, wherein the axial retainer secures the composite airfoil to the rotor.

[0116] A gas turbine engine according to any preceding clause, wherein the compliant component is made of rubber, polyurethane, urethane or a polymer.

[0117] A gas turbine engine as claimed in any preceding clause, wherein the composite component comprises a body and a compliant portion.

[0118] A gas turbine engine as described in any preceding clause, wherein the body defines a first yield strength and the compliant portion defines a second yield strength that is less than the first yield strength.

[0119] A gas turbine engine according to any preceding clause, further comprising a reinforcement member disposed within the compliant portion.

[0120] A gas turbine engine according to any preceding clause, wherein the reinforcement is made of the same material as the body.

[0121] A gas turbine engine as described in any preceding clause, wherein the compliant portion comprises at least one opening.

[0122] A gas turbine engine according to any preceding clause, wherein said at least one opening is arranged as a set of elongate apertures extending through said compliant portion.

[0123] A gas turbine engine according to any preceding clause, wherein the compliant portion is formed as a grid.

[0124] A gas turbine engine according to any preceding clause, wherein the grid is formed as a grid body.

[0125] A gas turbine engine according to any preceding clause, wherein the grid defines a plurality of spaces.

[0126] A gas turbine engine according to any preceding clause, wherein said plurality of spaces are empty.

[0127] A gas turbine engine as claimed in any preceding clause, wherein the compliant portion comprises an expanded material.

[0128] A gas turbine engine according to any preceding clause, wherein said expanded material contracts in a direction orthogonal to said force.

[0129] A gas turbine engine as claimed in any preceding clause, wherein said expansion material provides a non-linear response in response to said force.

[0130] A gas turbine engine as described in any preceding clause, wherein the compliant portion comprises foam.

[0131] A gas turbine engine as described in any preceding clause, wherein the foam comprises an open cell foam.

[0132] A gas turbine engine as described in any preceding clause, wherein the foam comprises a closed cell foam.

[0133] A gas turbine engine as described in any preceding clause, wherein the closed cell foam comprises a plurality of pores containing a gas.

[0134] A gas turbine engine as described in any preceding clause, wherein the gas is a pressurized gas having a pressure variable between 2 pounds per square inch absolute and 100 pounds per square inch absolute (2PSIA - 100PSIA).

[0135] A gas turbine engine as claimed in any preceding clause, wherein said pressure is greater than atmospheric pressure at ground level.

[0136] A gas turbine engine as claimed in any preceding clause, wherein the compliant portion is arranged as a set of springs.

[0137] A gas turbine engine as claimed in any preceding clause, wherein the set of springs are arranged as one or more of coil springs, leaf springs, spring fingers, wave springs, Belleville washers or split ring washers.

[0138] A gas turbine engine as claimed in any preceding clause, wherein the set of springs are arranged as a spring array.

[0139] A gas turbine engine according to any preceding clause, wherein the array of springs is arranged to compress in a direction aligned with the force.

[0140] A gas turbine engine as claimed in any preceding clause, wherein at least some of the springs in the set of springs are in a nested arrangement.

[0141] A gas turbine engine as claimed in any preceding clause, wherein at least some of the springs in the set of springs are in an offset arrangement.

[0142] A gas turbine engine according to any preceding clause, wherein the compliant portion is formed as a mosaic structure.

[0143] A gas turbine engine as claimed in any preceding clause, wherein the mosaic structure comprises a set of geometric units which are folded upon each other to form the mosaic structure.

[0144] A gas turbine engine as described in any preceding clause, wherein the compliant portion comprises a bladder.

[0145] A gas turbine engine as claimed in any preceding clause, wherein the compliant portion further comprises an outer wall surrounding the bladder.

[0146] A gas turbine engine according to any preceding clause, wherein the bladder is filled with a gas or a supercritical fluid.

[0147] A method for compliantly retaining a composite airfoil coupled to a disk using an axial retainer, the method comprising: deforming the axial retainer from a non-deformed shape to a deformed shape in response to a force; and at least partially returning the compliant portion from the deformed shape to the non-deformed shape after the force ceases.

[0148] A method as described in any preceding clause, wherein the force is provided by the composite airfoil abutting the axial retainer.

[0149] A method as in any preceding clause, wherein deforming the axial retainer further comprises deforming a compliant portion of the axial retainer.

[0150] A method as in any preceding clause, further comprising fully recovering from the deformed shape to the non-deformed shape after the force ceases.

[0151] A method as in any preceding clause, further comprising resisting deformation from the non-deformed shape by a reinforcement disposed within the compliant portion.

[0152] A method as in any preceding clause, wherein the compliant portion comprises an opening, and the deformation of the compliant portion comprises compression of the compliant portion at the opening.

[0153] A method as in any preceding clause, wherein the compliant portion is formed as a grid having a set of spaces, and wherein deformation of the compliant portion comprises compressing the grid into the set of spaces.

[0154] A method as in any preceding clause, wherein the compliant portion is formed as an expanded material.

[0155] A method as in any preceding clause, wherein deformation of the compliant portion comprises compressing the compliant portion in a direction orthogonal to the force.

[0156] A method as in any preceding clause, wherein the compliant portion comprises a closed cell foam having a plurality of cells, the plurality of cells containing a gas that compresses so as to deform from the non-deformed shape to the deformed shape.

[0157] A method according to any preceding clause, wherein the compliant portion is arranged as a set of springs, and wherein the set of springs collectively define a spring force, deform in response to the force, and return to the non-deformed shape after the force ceases.

[0158] A method as in any preceding clause, wherein the set of springs are arranged to compress in a direction aligned with the force.

[0159] A method according to any preceding clause, wherein the compliant portion is formed as a mosaic structure having a set of geometric units folded over one another, and wherein the set of geometric units can further be folded over one another so as to deform from the non-deformed shape in response to the force.

[0160] A method as in any preceding clause, wherein the compliant portion comprises a bladder filled with a gas or a supercritical fluid, and deformation of the compliant portion from the non-deformed shape to the deformed shape comprises compression of the bladder or the gas or the supercritical fluid.

Claims

1. A gas turbine engine, characterized in that: include: a fan section, a compressor section, a combustion section, and a turbine section, the fan section, the compressor section, the combustion section, and the turbine section being in a serial flow arrangement and defining an engine centerline extending between a forward direction and an aft direction; a disk disposed in one of the fan section, the compressor section, or the turbine section and comprising a slot; a composite airfoil coupled to the disk at the slot; and an axial retainer coupled to the disk and securing the composite airfoil within the slot, the axial retainer including a compliant portion positioned adjacent the composite airfoil; Wherein the compliant portion is deformable from a non-deformed shape to a deformed shape in response to a force from the composite airfoil acting on the axial retainer, and wherein the compliant portion at least partially recovers to its non-deformed shape after the force ceases.

2. The gas turbine engine according to claim 1, characterized in that in, The axial retainer includes a metallic body, and wherein the compliant portion is non-metallic.

3. The gas turbine engine according to claim 2, characterized in that in, The compliant portion fully recovers to the non-deformed shape after the force ceases.

4. The gas turbine engine according to claim 1, characterized in that in, The compliant portion expands in a direction orthogonal to the force.

5. The gas turbine engine according to claim 1, characterized in that in, The compliant portion is made of rubber, polyurethane, urethane or a polymer.

6. The gas turbine engine according to claim 1, characterized in that in, The compliant portion is disposed forwardly of the composite airfoil.

7. The gas turbine engine according to claim 1, characterized in that in, The axial retainer includes a body, and the compliant portion is coupled to the body.

8. The gas turbine engine according to claim 7, characterized in that in, The body is metallic and defines a first bulk modulus.

9. The gas turbine engine according to claim 8, characterized in that in, The compliant portion defines a second bulk modulus that is less than the first bulk modulus.

10. The gas turbine engine according to claim 7, characterized in that in, The body defines a first yield strength, and the compliant portion defines a second yield strength that is less than the first yield strength.

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