Gas turbine engine with composite airfoil and method of forming

Abstract

A gas turbine engine includes a fan section, a compressor section, a combustor section, and a turbine section in a serial flow arrangement and defines an engine centerline extending from a front portion to an aft portion. A composite airfoil disposed in one of the fan section, the compressor section, or the turbine section may have an equilibrium mass distribution. The woven core defines a first mass distribution. The set of layouts coupled to the woven core collectively define a second mass distribution, where the second mass distribution is closer to the equilibrium mass distribution than the first mass distribution.

Description

Technical Field

[0001] The present disclosure relates generally to components of gas turbine engines and, more particularly, to composite airfoils and methods of forming composite airfoils. Background Art

[0002] A gas turbine engine typically includes an engine core having a compressor section, a combustor section, and a turbine section in a serial flow arrangement. In a bypass turbine engine, the fan section may be located 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 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 producing useful work to propel an aircraft in flight or to power a load such as an electrical generator.

[0003] Many components of gas turbine engines are made from composite materials, which may include a fiber-reinforced matrix and exhibit a high strength-to-weight ratio. Due to the high strength-to-weight ratio and the ability to form relatively complex shapes, composite materials are used in various applications, such as gas turbine engines or aircraft. For example, components made from composite materials may be mounted on or define a portion of a fuselage and / or wings, rudders, manifolds, airfoils, blades, vanes, or other components of an aircraft or gas turbine engine. 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 gas turbine engine according to aspects of the present disclosure.

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

[0007] Figure 3 is a method according to aspects of the present disclosure comprising a set of plies disposed on a woven core Figure 2 Schematic diagram of a composite airfoil assembly.

[0008] Figure 4 is a flow chart illustrating a method of forming a composite airfoil according to aspects of the present disclosure. DETAILED DESCRIPTION

[0009] Aspects disclosed herein relate to preforms or manufacturing cores for engine components, such as airfoils. The core may be a woven core and may include one or more woven layers that form the engine component. The woven core is used to create an engine component for a gas turbine engine. For example, such an engine component may be an airfoil. However, it should be understood that, in non-limiting examples, the present disclosure is applicable to other engine components of a gas turbine engine, such as a combustor liner, a shroud, a nozzle, or a disk. Furthermore, although described in terms of a core for manufacturing an airfoil or an aircraft, it should be understood that the present disclosure is applicable to any other suitable environment, such as terrestrial or non-terrestrial, airborne, land-based or non-land-based applications.

[0010] 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 designations to refer to features in the drawings. Like or similar designations in the drawings and the description have been used to refer to like or similar parts of the disclosure.

[0011] 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. Furthermore, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0012] 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.

[0013] As used herein, the term "upstream" refers to a direction opposite to the direction of fluid flow, while the term "downstream" refers to a direction in the same direction as the direction of fluid flow. The term "front" means in front of something, and "rear" or "rearward" means behind something. For example, when used in relation to fluid flow, front / front may refer to upstream, and rear / rearward may refer to downstream.

[0014] The term "fluid" may be gas or liquid, or multiple phases.

[0015] As used herein, the term "radial" or "radially" refers to directions away from a common center. For example, in the overall context of a gas turbine engine, radial refers to directions along a ray extending between the central longitudinal axis of the engine and the engine periphery.

[0016] All directional references as may be used herein (e.g., radial, axial, coaxial, top, upstream, downstream, front, rear, etc.) are for identification purposes only to help the reader understand the present disclosure and do not create limitations, particularly with respect to the position, orientation, or use of the disclosed aspects described herein. Connection references (e.g., coupling, connecting) are to 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 figures are for illustration purposes only, and the dimensions, positions, orders, and relative sizes reflected in the accompanying figures may vary.

[0017] 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 can refer to any number of elements, including only one.

[0018] As used herein, the terms "weight" or "mass" refer to an intrinsic property of a component or part thereof that relates to the amount of matter present. Weight can be defined by the mass of an object under the influence of gravity on Earth.

[0019] As used herein, the terms "moment weight" or "moment mass" may refer to weight or mass multiplied by the distance from the axis of rotation. The axis of rotation may be defined as rotation about the engine centerline or axis of rotation, or about a point on the engine centerline or axis of rotation. "Moment weight" or "moment mass" may be determined as the mass of a component or portion thereof multiplied by the distance from the engine centerline or axis of rotation to the center of mass of the component.

[0020] As used herein, the term "center of mass" may refer to a point defined by a component that represents the average mass of the component. As used herein, the term "center of rotation" may relate to an axial position or point along an engine centerline or axis of rotation aligned with the center of mass, defined in a direction orthogonal to the engine centerline or axis of rotation (such as in a radial direction about the axis of rotation).

[0021] As used herein, the terms "mass distribution," "first mass distribution," or "second mass distribution" may refer to the spatial distribution of mass or matter within a component or portion thereof. Weight, mass, thickness, local thickness, moment weight, moment mass, center of mass, and center of rotation may be defined based on the "mass distribution," "first mass distribution," or "second mass distribution." "Mass distribution," "first mass distribution," or "second mass distribution" refers to the distribution of mass or matter that collectively defines the weight and mass of a component. The specific arrangement of the mass or matter defines the geometry of the component, which in turn defines the thickness or local thickness. The "mass distribution," "first mass distribution," or "second mass distribution" of mass or matter further defines moment weight or moment mass, wherein the distribution of the mass or matter defines the center of mass, and the moment weight or moment mass of the component can be defined based on the center of mass multiplied by the distance from the engine centerline or axis of rotation. The "mass distribution," "first mass distribution," or "second mass distribution" of mass or matter further defines the center of rotation of the component along the engine centerline or axis of rotation, where the center of rotation is determined based on the center of mass of the component aligned orthogonally to the engine centerline or axis of rotation. As used herein, "balanced mass distribution" may refer to a state of a component or airfoil in which the mass distribution is arranged so that the center of mass of the component is aligned with the equilibrium center of mass and is aligned orthogonally with the equilibrium center of rotation. Similarly, an "unbalanced mass distribution" may be defined by a misalignment or offset between the center of mass and the equilibrium center of mass or the equilibrium center of rotation. Balancing a component may include changing the mass distribution so that the physical center of mass of the component is aligned with the equilibrium center of mass and the equilibrium center of rotation. As used herein, the term "cured mass distribution" may refer to the mass distribution of a component after curing the component.

[0022] 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 include, but are not limited to, polymer matrix composites (PMCs), ceramic matrix composites (CMCs), metal matrix composites (MMCs), carbon fibers, polymer resins, thermoplastic resins, bismaleimide (BMI) materials, polyimide materials, epoxy resins, glass fibers, and silicon matrix materials.

[0023] As used herein, a "composite" component refers to a structure or component comprising any suitable composite material. A composite component, such as a composite airfoil, may comprise several layers or several layups of composite material. The mechanical properties, materials, and dimensions of the layers or layups may be varied to achieve a specific composite component or composite portion of a component having a predetermined weight, size, or mechanical properties.

[0024] One or more layers of adhesive may be used to form or join the composite parts. The adhesive may include resins and phenolics, wherein the adhesive may be cured at elevated temperatures or other hardening techniques.

[0025] As used herein, PMC refers to a class of materials. As an example, PMC materials are defined in part by prepregs, which are reinforcing materials pre-impregnated with a polymer matrix material (e.g., a thermoplastic resin). Non-limiting examples of processes for producing thermoplastic prepregs include: hot melt prepregs, in which a fiber reinforcement is pulled through a molten bath of resin; and powder prepregs, in which resin is deposited onto the fiber reinforcement, as a non-limiting example, electrostatically deposited onto the fiber reinforcement, 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 produce a number of stacked layers forming a part.

[0026] Multilayer prepreg is stacked to the appropriate thickness and orientation of composite component, 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 repeatedly soften and flow when heated and can harden due to physical change rather than chemical change when fully cooled. The famous example category of thermoplastic resin includes nylon, thermoplastic polyester, polyaryletherketone and polycarbonate resin. The specific example of the high performance thermoplastic resin envisioned for aerospace application includes polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyaryletherketone (PAEK) and polyphenylene sulfide (PPS). On the contrary, once fully cured into hard rigid solid, thermosetting resin will not experience significant softening when heated, but will thermally decompose when fully heated. The famous example of thermosetting resin includes epoxy resin, bismaleimide (BMI) and polyimide resin.

[0027] Instead of using prepreg, in another non-limiting example, woven fabrics can be utilized by using thermoplastic polymers. Woven fabrics may include, but are not limited to, dry carbon fibers woven together with thermoplastic polymer fibers or filaments. Non-prepreg braided architectures can be made in a similar manner. In this way, the fiber volume of a part can be customized by specifying the relative concentrations of the thermoplastic fibers and reinforcing fibers that have been woven or braided together. In addition, different types of reinforcing fibers can be woven or woven together at different concentrations to customize the properties of the part. For example, glass fiber, carbon fiber, and thermoplastic fibers can be woven together at different concentrations to customize the properties of the part. Carbon fiber provides the strength of the system and can be incorporated with glass fiber to enhance impact properties, which is a design feature of parts located near the engine inlet, and thermoplastic fibers provide bonding for the reinforcing fibers.

[0028] 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 involves applying a dry fiber or matrix material to a mold or cavity. The dry fiber or matrix material can include a prepreg, a braided material, a woven material, or any combination thereof.

[0029] Resin can be pumped or otherwise supplied to the mold or cavity to impregnate the dry fibers or matrix material. The impregnated fibers or matrix material and resin combination is then cured and removed from the mold. Upon removal from the mold, the composite part can be completed through a post-curing process.

[0030] It is contemplated that RTM can be a vacuum-assisted process. That is, the air in the cavity or mold can be removed and replaced with resin before heating or curing. It is further contemplated that the placement of dry fiber or matrix material can be manual or automated.

[0031] The dry fiber or matrix material can 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 can also be included or added before heating or curing.

[0032] 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.

[0033] 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.

[0034] In general, specific CMCs can be referred to by 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 a silicon carbide fiber-reinforced silicon carbide / silicon nitride matrix mixture, and so on. In other examples, CMCs can be composed of a matrix comprising oxide-based materials such as aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, and mixtures thereof, and reinforcing fibers. Aluminosilicates can include crystalline materials such as mullite (3Al2O3·2SiO2), as well as glassy aluminosilicates.

[0035] In certain non-limiting examples, the reinforcing fibers may be bundled and / or coated prior to inclusion in the ceramic matrix. For example, the fiber bundles may be formed into reinforcement tapes, such as unidirectional reinforcement tapes. Multiple tapes may be stacked together to form a preform component. The fiber bundles may be impregnated with the slurry composition before or after forming the preform. The preform may then be subjected to a heat treatment and subsequent chemical treatment to obtain a component formed from a CMC material having a specific chemical composition. For example, the preform may undergo curing or burnout to produce a high coke residue in the preform and then be melt infiltrated with silicon, or undergo curing or pyrolysis to produce a silicon carbide matrix in the preform and then be chemically vapor infiltrated 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, followed by 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 infusion pyrolysis (PIP), or any combination thereof.

[0036] Such materials, along with certain monolithic ceramics (i.e., ceramic materials without reinforcements), are particularly well-suited for higher temperature applications. Furthermore, these ceramic materials are lightweight compared to superalloys while still providing strength and durability to components made from them. Consequently, 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., turbine blades and buckets), combustors, shrouds, and other components, which would benefit from the lighter weight and higher temperature capabilities that these materials can offer.

[0037] The term "metal" as used herein refers to materials 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.

[0038] As used herein, the term "preform" is a three-dimensional composite material formed from a plurality of fibers or yarns, including warp fibers or yarns and weft fibers or yarns. At least some of the fibers or yarns may be integrated into the preform by weaving, stitching, tufting, or any other suitable manufacturing process. A preform as referred to herein is a fully formed component formed in a separate manufacturing process from a fully formed component.

[0039] The inventors' practice proceeded in the manner described above (i.e., designing a core for manufacturing a component such as an airfoil; designing an airfoil with improved balance and rotational balance; identifying whether the component was manufactured as designed and met component objectives; and modifying the engine component with new geometric characteristics in an iterative process when the engine component did not meet the component objectives). Figure 1 This process is repeated during the design of the PCB (those shown in FIG).

[0040] Figure 1 is a schematic cross-sectional view of a gas turbine engine 10 for an aircraft. The gas turbine engine 10 has a generally longitudinally extending axis or engine centerline 12 extending from a front portion 14 to an aft portion 16, with the front portion 14 and the aft portion 16 defining forward and aft directions, respectively. The gas 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. As shown, the turbine engine 10 is a turbofan engine. However, it should be understood that the turbine engine 10 may be any suitable engine, such as, but not limited to, a turboprop engine, a turboshaft engine, a ducted turbofan engine, a non-ducted engine, or an open rotor turbine engine.

[0041] 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 about the engine centerline 12. The HP compressor 26, the combustor 30, and the HP turbine 34 form an engine core 44 of the gas turbine engine 10, which generates combustion gases. The engine core 44 is surrounded by a core case 46, which can be coupled to the fan case 40.

[0042] An HP shaft or spool 48 is coaxially disposed about the engine centerline 12 of the gas turbine engine 10 and drivingly connects the HP turbine 34 to the HP compressor 26. An LP shaft or spool 50, coaxially disposed about the engine centerline 12 of the gas turbine engine 10 within the larger diameter of the 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.

[0043] 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 passing 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 number of blades, buckets, and compressor stages shown in FIG. 5 are chosen for illustration purposes only, and other numbers are possible.

[0044] Compressor blades 56, 58 for one stage of the compressor may be mounted to (or integrated into) a disk 61 mounted to a respective one of the HP and LP spools 48, 50. Static compressor vanes 60, 62 for one stage of the compressor may be mounted to the core housing 46 in a circumferential arrangement.

[0045] The HP turbine 34 and the LP turbine 36 each include a plurality of turbine stages 64, 66, in which a set of turbine blades 68, 70 rotate relative to a corresponding set of static turbine vanes 72, 74 (also known as nozzles) to extract energy from the 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 is selected for illustration purposes only; other numbers are possible.

[0046] Turbine blades 68, 70 for one stage of the turbine may be mounted to a disk 71 mounted to a respective one of the HP and LP spools 48, 50. Static turbine buckets 72, 74 for one stage of the compressor may be mounted to the core housing 46 in a circumferential arrangement.

[0047] Complementing the rotor portion, the stationary portion of the gas turbine engine 10, such as the stationary blades 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 gas turbine engine 10.

[0048] In operation, the airflow exiting the fan section 18 is split so that a portion of the airflow is directed to the LP compressor 24, which then supplies 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 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 to the LP turbine 36, which extracts additional work to drive the LP compressor 24, and the exhaust gas is exhausted from the gas 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.

[0049] A portion of the pressurized airflow 76 may be extracted from the compressor section 22 as bleed air 77. The bleed air 77 may be extracted from the pressurized airflow 76 and provided to engine components that utilize cooling. The temperature of the pressurized airflow 76 entering the combustor 30 is significantly increased to a temperature above the bleed air temperature. The bleed air 77 may be used to reduce the temperature of core components downstream of the combustor 30.

[0050] The airflow exiting the remainder of the fan section 18 bypasses the LP compressor 24 and the engine core 44 as bypass airflow 78 and exits the gas turbine engine 10 through a stationary blade row at the fan exhaust side 84, and more specifically, exits the gas turbine engine 10 through an outlet 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 is employed adjacent the fan section 18 to exert some directional control on the bypass airflow 78.

[0051] Some of the air supplied by the fan 20 may bypass the engine core 44 and be used to cool portions of the gas turbine engine 10, particularly the hot portion, and / or to cool or power other aspects of the aircraft. In the case of the gas turbine engine 10, the hot portion of the engine is 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.

[0052] Figure 2is an exploded view of an airfoil assembly including an assembly 100 comprising a rotatable disk 102 and a Figure 1 A composite airfoil 104 for use within a turbine engine 10 .

[0053] Composite airfoil 104 includes an airfoil portion 106 and a dovetail portion 108 extending from airfoil portion 106. For illustrative purposes, a transition 128 between dovetail portion 108 and airfoil portion 106 has been shown in phantom. Dovetail portion 108 may define a portion of composite airfoil 104 that flares circumferentially outward from airfoil portion 106.

[0054] Airfoil portion 106 includes an outer wall 110. Outer wall 110 extends between a leading edge 112 and a trailing edge 114 to define a chordwise direction. Airfoil portion 106 extends between a root 116 and a tip 118 to define a spanwise direction. Dovetail portion 108 terminates radially at root 116. Airfoil portion 106 includes a pressure side 120 and a suction side 122.

[0055] The composite airfoil 104 is coupled to the disk 102 by inserting at least a portion of the composite airfoil 104, such as the dovetail portion 108, into a corresponding slot in a plurality of slots 124 extending into an exterior surface 126 of the disk 102. The composite airfoil 104 is held in place by frictional contact with the slots 124 or may be coupled to the slots 124 via any suitable coupling method, such as, but not limited to, welding, bonding, fastening, etc. Although only a single composite airfoil 104 is shown, it should be understood that any number of one or more composite airfoils 104 may be coupled to the disk 102. As a non-limiting example, there may be a number of composite airfoils 104 corresponding to the total number of slots in the plurality of slots 124.

[0056] For ease of reference, a set of relative reference directions and coordinate systems may be applied to the composite airfoil 104 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. In a non-limiting example, the axial direction (Ad) may 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 locally defined as being perpendicular to the radial direction (Rd), and the circumferential direction (Cd) may be defined along a curvature of a circle about the axial direction (Ad), and / or may be defined along the gas turbine engine 10 ( Figure 1 ) is defined relative to the circumference of the engine centerline 12.

[0057] Figure 3 Shown Figure 2Schematic diagram of a composite airfoil 104, composite airfoil 104 includes a woven core 150 and a skin layer 152 positioned outside the woven core 150. A set of plies 154 can be arranged on or outside the woven core 150, as well as inside the skin layer 152. The woven core 150 can be made at least in part of a woven structure. In a non-limiting example, the woven core 150 can be formed as a preform, or the woven core 150 with the set of plies 154 can be formed as a preform. In a non-limiting example, the woven structure of the woven core 150 can include a set of fibers 156, which can include a set of warp fibers 158 and a set of weft fibers 160. The set of warp fibers 158 and the set of weft fibers 160 can be staggered or interwoven to at least partially form the woven core 150. In one non-limiting example, a Jacquard loom or 3D loom may be used to create a complex woven structure, which may include interweaving one or more materials or composite materials to form the woven core 150. In a non-limiting example, such materials or composite materials may include carbon or carbon fibers, glass or fiberglass, nylon, rayon, or other aramid fibers, while other materials such as nickel, titanium, or ceramic composites are contemplated.

[0058] In one non-limiting example, the first weave pattern may be a three-dimensional weave pattern. More specifically, the weave structure may be woven in the axial direction (Ad), the radial direction (Rd), and the circumferential direction (Cd) ( Figure 2 ) of a combination of woven fabrics, wherein the circumferential direction (Cd) extends into and out of the page, such as Figure 3 As shown. In another non-limiting example, the woven core 150 may include a braided weave pattern. For example, the braided weave pattern may include a weave pattern that includes three or more interwoven fibers woven in a repeating pattern. In another non-limiting example, the braided geometry may include a group of fibers or strands sequentially stacked on top of each other to define the braided geometry. It should be understood that the weave pattern can be formed and defined in any three mutually orthogonal planes so as to define a three-dimensional object relative to the planes. For example, the three mutually orthogonal planes may include a first plane defined between the spanwise direction and the chordwise direction, and two additional mutually orthogonal planes, both of which are arranged to be orthogonal to the first plane and to be orthogonal to each other.

[0059] The woven core 150 can be made of an incoming raw material such as carbon or carbon fiber, glass or fiberglass, nylon, rayon or other aramid fibers, nickel, titanium or ceramic composites, and combinations thereof, or other suitable composite materials can be envisioned. The woven core 150 including the first group of fibers 156 (having the group of warp fibers 158 and the group of weft fibers 160) can be made of a raw material. The raw material can have material properties such as mass, weight, stiffness, moment weight, moment mass that can define the center of mass or mass distribution of the woven core 150. Utilizing the material properties of the raw material can be used to determine the application of the group of plies 154, such as the amount or location of the group of plies 154. Such material properties can be used to determine the application of the group of plies 154 to the woven core 150 on a group of manufactured composite airfoils 104 without having to measure or inspect each woven core 150.

[0060] The set of plies 154 may be added to the exterior of the woven core 150 prior to application of the skin layer 152. Each ply in the set of plies 154 may be a single ply, while multiple plies are contemplated. As shown, the set of plies 154 extends partially between the root 116 and the tip 118, while it is contemplated that the set of plies 154 may extend completely between the root 116 and the tip 118, between the leading edge 112 and the trailing edge 114, or between only a portion thereof. Additionally, each individual ply in the set of plies 154 may be different from another ply in the set of plies 154. For example, the spanwise length of the set of plies 154 may vary, with each outer ply in the set of plies 154 becoming progressively shorter, covering a smaller area, chordwise extent, spanwise extent, or a combination thereof of the composite airfoil 104. Additionally, the set of plies 154 may be located on the pressure side 120 or the suction side 122 ( Figure 2 ), or both. Additionally, it is contemplated that the arrangement of the set of plies 154 may be arranged as more than one set of plies, with regions or groups of the multiple sets of plies 154 disposed at different locations or portions of the composite airfoil 104. This arrangement may be symmetrical (such as sharing symmetry in the spanwise, chordwise directions between the pressure side 120 or the suction side 122), or may be asymmetrical, with discrete or localized arrangements of the multiple sets of plies 154.

[0061] The skin layer 152 is positioned outside the woven core 150 and the group of plies 154 and can be disposed on or applied to the woven core 150 and the group of plies 154. In a non-limiting example, the skin layer 152 can be a laminate and can be formed as a plurality of laminates or laminated plies formed together to define the skin layer 152. In additional non-limiting examples, the skin layer 152 can be made of a composite material similar or different from the woven core 150 (such as carbon or carbon fiber, glass or glass fiber, nylon, rayon or other aramid fibers), and in a non-limiting example, can be made of other materials (such as nickel, titanium or ceramic composites). The size and shape of the skin layer 152 can be designed to form the final airfoil shape, such as defining a larger or smaller local geometry, mass or thickness outside the woven core 150 and the group of plies 154. An outer coating (not shown) disposed on the skin layer 152 can form the outer wall, and it is contemplated that one or more additional inner or outer layers may be disposed within or outside the skin layer 152. In one non-limiting example, the outer coating may be a barrier coating, for example to prevent erosion due to impact, and additional properties such as a hydrophobic or ice-phobic coating, a corrosion-resistant or erosion-resistant coating, or a UV-resistant coating are contemplated. Additional finishing layers or materials may be provided, such as an oxidation-resistant or corrosion-resistant coating or paint. An intermediate adhesive layer is further contemplated.

[0062] During manufacture, the woven core 150 has a first mass distribution defining, among other material properties of the woven core 150, mass (grams or pounds (lbs)), moment mass (inch-pounds), thickness (meters), a first center of mass 170, and a first mass distribution that is circumferentially about the engine centerline 12 ( Figure 1) is rotated about a first center of rotation 172. Differences between the raw materials or composite materials used to manufacture the woven core 150 result in manufacturing differences from the balanced mass distribution across multiple production units, such as the first center of mass 170 being offset from the balanced center of mass 174, and the first center of rotation 172 being offset from the balanced center of rotation 176. This offset can be defined in any direction (such as the axial direction (Ad), the radial direction (Rd), or the circumferential direction (Cd), or any combination thereof). In order to ensure proper airfoil balance, it is necessary to account for differences that develop in the woven core 150 during manufacturing, whether as a result of the manufacturing itself or the specific raw materials used. Therefore, in the case where the woven core 150 includes a first center of mass 170 that is offset from the balanced center of mass 174, or in the case where the first center of rotation 172 is offset from the balanced center of rotation 176, it is desirable to complete the manufacturing of the composite airfoil 104 in a manner that balances the composite airfoil 104 by aligning the first center of mass 170 with the balanced center of mass 174, or by aligning the first center of mass 170 with the balanced center of rotation 176, or both. As the number of fan blades decreases and / or the mass of the fan blades increases, the forces generated by the unbalanced mass distribution will increase, thereby increasing the impact of the unbalanced airfoil on the gas turbine engine 10 ( Figure 1 ) requires greater care to ensure proper airfoil balance.

[0063] In addition, the curing of the woven core 150 can change the mass distribution, resulting in the movement of the first mass center 170 during the curing of the woven core 150. The curing of the woven core 150 can define a cured mass distribution having a cured mass center and a cured rotation center. It is within the scope of this disclosure to consider the changes or differences in the mass distribution caused by curing the woven core 150, the group of plies 154, or other parts of the composite airfoil 104. In other words, curing the woven core 150 can result in a cured mass distribution different from the first mass distribution having the first mass center 170 and the first rotation center 172. One or both of the first mass center 170 or the first rotation center 172 can be different from the cured mass center or the cured rotation center, respectively. In this way, the curing of the woven core 150, the group of plies 154, or other parts of the composite airfoil 104 can be used to change the mass distribution to balance the composite airfoil 104, or curing can be considered during the addition of the group of plies 154 so that the cured composite airfoil 104 defines a mass distribution that matches or is more closely aligned with the balanced mass distribution.

[0064] To determine and account for any differences, the manufacturing of the woven core 150 can take into account the specific raw material used in forming the woven core 150, which can dictate the application, location, or amount of the set of plies 154 added to the woven core 150. For example, where a first raw material has a mass or weight defining a first mass distribution, the set of plies 154 can be added to alter the overall mass distribution of the woven core 150, thereby balancing the woven core 150 by aligning the first center of mass 170 with the equilibrium center of mass 174. In this manner, it should be understood that manufacturing using a specific raw material can predict the location, quantity, thickness, material, or other aspects of the set of plies 154 to be applied across a full set of manufactured composite airfoils 104 or other units. This prediction can be applied to a wide range of units, woven cores 150, composite airfoils 104, or other similar materials in a composite material, allowing the set of plies 154 to be applied consistently across multiple units, thereby achieving balance across multiple woven cores 150, without having to measure each woven core 150 before applying the set of plies 154.

[0065] In another non-limiting example, the woven core 150 can be measured to determine the mass distribution, such as considering size, volume, mass, material, moment mass, center of rotation, center of mass, local thickness, or a combination thereof in a non-limiting example. These measurements are used to determine the mass distribution of the woven core 150, thereby determining the first center of mass 170 and the first center of rotation 172. The first center of mass 170 and the first center of rotation 172 can be compared with expected values, such as compared with a balanced mass distribution including a balanced center of mass 174 or a balanced center of rotation 176. Any difference between the measured value and the value defined by the balanced center of mass 174 and the balanced center of rotation 176 indicates that the composite airfoil 104 can be balanced by adding the group of plies 154. Specifically, where the first center of mass 170 is misaligned, spaced apart, or offset from the equilibrium center of mass 174, or where the first rotational center 172 is misaligned, spaced apart, or offset from the equilibrium center of mass 176, the addition of the set of plies 154 or the curing of the composite airfoil 104 can be used to move the first center of mass 170, collectively defined by the woven core 150 and the set of plies 154, to align with the equilibrium center of mass 174, or to move the first rotational center 172 to align with the equilibrium center of rotation 176, thereby balancing the composite airfoil 104. The set of plies 154 defines its own mass distribution as a second mass distribution having a second center of mass 178 corresponding to a second center of rotation 180. Applying the set of plies 154 to the woven core 150 collectively defines a combined mass distribution including a combined center of mass 182 and a combined center of rotation 184, which can correspond to the equilibrium center of mass 174 and the equilibrium center of rotation 176, respectively. Adding this group of plies 154 changes the first mass distribution of the woven core 150 into a combined mass distribution that can correspond to or be aligned with an equilibrium mass distribution. Despite differences between the raw materials, such addition of this group of plies 154 or curing of the woven core 150 and this group of plies 154 allows for a balanced formation of the composite airfoil 104. Additionally, the addition of this group of plies 154 may be subject to structural, dimensional, or weight constraints that may not allow for complete alignment between the combined mass distribution and the equilibrium mass distribution. In such an example, it will be understood that the application of this group of plies 154 can move the combined center of mass or the combined center of rotation closer to the equilibrium center of mass or the equilibrium center of rotation, closer than the first mass distribution, the first center of mass, or the first center of rotation, without being fully aligned.

[0066] Additionally, it is contemplated that adding the set of plies 154 can be accomplished in anticipation of adding the skin layer 152. That is, adding the set of plies 154 can alter the woven core 150 in anticipation of adding the skin layer 152. More specifically, it is contemplated that adding the set of plies 154 can result in an offset or misalignment with the equilibrium center of mass 174 or the equilibrium center of rotation 176, which is expected to align upon adding the skin layer 152, in situations where adding the skin layer 152 can alter the mass distribution in a manner that changes the position of the first center of mass 170 or the first center of rotation 172 away from the equilibrium mass distribution. Adding the skin layer 152 or the set of plies 154 can account for the expected differences left by the set of plies 154 or the expected differences caused by adding the skin layer 152 itself, such that applying the skin layer 152 external to the set of plies 154 alters the first center of mass 170 to align with the equilibrium center of mass 174 or alters the first center of rotation 172 to align with the equilibrium center of rotation 176. The addition of the skin layer 152 can change the mass distribution by changing the size, mass, volume, moment mass, center of mass, center of rotation, or local thickness of the composite airfoil 104. Even in the case where the skin layer 152 is uniformly disposed on the woven core 150 and the set of plies 154, differences in the shape and geometry of the woven core 150 can result in the skin layer 152 being unevenly applied to the composite airfoil 104. Therefore, it is within the scope of the present disclosure to provide the set of plies 154 to account for expected differences in size, volume, mass, moment mass, center of rotation, center of mass, or local thickness resulting from the skin layer 152. In a further non-limiting example, it is contemplated that the set of plies 154 can be applied at least partially exterior to the skin layer 152, with additional exterior or finishing layers disposed exterior to the skin layer 152 and the set of plies 154.

[0067] refer to Figure 4 , forming a composite airfoil (such as composite airfoil 104 ( Figure 3 )), or for a gas turbine engine such as gas turbine engine 10 ( Figure 1 )) or for another composite component other than a turbine, or a non-aircraft component, method 200. The composite airfoil 104 may include a balanced mass distribution that allows for balanced rotation or operation when used within the gas turbine engine 10. The method 200 includes forming a core defining a first mass distribution at 202. In a non-limiting example, the core may be a woven core 150 ( Figure 3 ), and in additional non-limiting examples, the core can be a braided core or a laminated core. The woven core 150 can be made of a raw material or a group of raw materials having one or more material properties that define a first center of mass 170 offset from a center of mass 174 of equilibrium.

[0068] At 204, the method 200 may include curing the woven core 150. During curing of the woven core 150, the thickness or density of the raw material or the group of raw materials may change due to the curing process. Within the scope of the present disclosure, the first mass distribution may change during curing of the woven core 150, such that the first mass distribution is represented as a post-curing first mass distribution, while an uncured first mass distribution may be contemplated.

[0069] At 206, method 200 may include measuring the woven core 150 to determine a first mass distribution of the formed core. In a non-limiting example, the measurements may include weighing the woven core 150, determining the dimensions of the woven core 150, and determining the spatial distribution of mass within the woven core 150. In a non-limiting example, modeling may be used to determine the first mass distribution, such as using non-homogeneous differential analysis. Measuring the woven core 150 may be used to output the first mass distribution. In the event that the application of the set of plies 154 is based on the material properties of the raw material used to form the woven core 150, it is contemplated that the measurements at 206 may be based on the material properties of the raw material rather than measurements of the woven core 150. For example, in the event that the application of the set of plies 154 is based on the material properties of the raw material, the woven core 150 to which the set of plies 154 has been added may be measured to ensure that balance has been achieved or is within an acceptable threshold, and to ensure that the application of the set of plies 154 to the set of multiple units achieves proper balance for the set of multiple units. For multiple manufactured composite airfoils 104 , it may be impractical to measure each individual woven core 150 . Utilizing common variances across multiple units that are specific to a particular raw material allows for balancing multiple units without measuring each individual woven core 150 .

[0070] At 208, method 200 may include comparing the first mass distribution to the equilibrium mass distribution to define an unbalanced mass distribution. The unbalanced mass distribution may be a value or representation of a difference between the formed core and the equilibrium mass distribution. Differences between the raw materials or composite materials may cause the first mass distribution to differ from the equilibrium mass distribution. The unbalanced mass distribution may represent the difference between the first mass distribution and the equilibrium mass distribution.

[0071] At 210, method 200 may include coupling, laminating, or otherwise applying a set of plies to woven core 150, such as set of plies 154 ( Figure 4). The set of plies can be positioned or arranged on the woven core 150, which can collectively define a second mass distribution. Determining the location, thickness, mass, amount, or type of material used for the set of plies can be based on the unbalanced mass distribution determined at 208, or based on the raw material used to form the woven core 150 at 202. Specifically, the set of plies 154 can be applied to change the first mass distribution, which can be based on the unbalanced mass distribution, so that the second mass distribution more closely matches or more closely matches the balanced mass distribution.

[0072] At 212, method 200 may include curing the woven core 150 with the set of plies 154. During curing, the thickness of the material may change due to the curing process. Within the scope of the present disclosure, the second mass distribution may change during curing, and the balanced mass distribution may account for changes during curing of the component.

[0073] At 214, method 200 may include measuring the woven core 150 with this group of plies. In a non-limiting example, measurement may include weighing the woven core 150, determining the size of the woven core 150, and determining the spatial distribution of the mass in the woven core 150. In a non-limiting example, modeling may be used to determine the second mass distribution such as using a non-homogeneous differential analysis. Measuring after applying this group of plies 154 to the woven core 150 may ensure that the second mass distribution matches the equilibrium mass distribution, or that this difference from the equilibrium mass distribution is within an acceptable threshold. In one example, the woven core 150 with this group of plies 154 may be utilized to determine the accurate balance relative to the raw materials used to form the woven core 150, which may be applied to a whole group of manufacturing units. The measurement of the initial unit may determine whether proper balance is achieved, and should be appropriately applied to multiple manufacturing units.

[0074] At 216, the method 200 may include adding a skin layer, such as the skin layer 152 ( Figure 3). In a non-limiting example, adding the skin layer 152 can also include curing the skin layer 152 or finishing the skin layer 152. It should be further understood that the skin layer 152 can be cured, and it is contemplated that the curing of the skin layer 152 can be completed at the same time as the woven core 150 is cured. In such an example, it is contemplated that applying the skin layer at 216 can be completed before curing the core at 204 or 212, so that the curing of the entire composite airfoil 104 or a portion thereof (such as the woven core 150) can be completed at the same time as the curing of the skin layer 152. It should be understood that the curing of one or more portions can be performed simultaneously, and it is within the scope of the method 200 to couple the application of the skin layer 152 and its curing to the curing of other portions of the composite airfoil 104. Additionally, any other finishing features or analysis can be added or performed, such as, in a non-limiting example, adding an exterior coating to the exterior of the skin layer.

[0075] Aspects described herein provide processes or methods for forming components (such as airfoils), and the components themselves formed, that provide improved balance despite differences from the raw materials. This improved balance improves efficiency, as well as extends component life and reduces maintenance. As gas turbine engines seek to reduce the number of blades, the balance of each blade becomes increasingly important. Aspects disclosed herein allow for balancing composite airfoils having a woven core suitable for use with a reduced number of blades. Exploiting differences in the raw materials can reduce manufacturing costs and time, as well as reducing or eliminating measurements of multiple manufacturing units, reducing the time required to ensure manufacturing balance. This increased efficiency and life, combined with reduced maintenance, results in reduced costs. In addition, the aspects described herein provide better control over final airfoil weight, moment weight, and thickness, which results in better control over airfoil balance.

[0076] 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 devices or systems and performing any incorporated methods. 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. If such other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims, such other examples are intended to be within the scope of the claims.

[0077] Further aspects are provided by the subject matter of the following clauses:

[0078] A gas turbine engine comprising: 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; and at least one composite airfoil disposed in one of the fan section, the compressor section, or the turbine section and rotatable about the engine centerline, the at least one composite airfoil having a balanced mass distribution defining a balanced center of mass aligned with a balanced rotational center disposed along the engine centerline, wherein the at least one composite airfoil comprises: a woven core defining a first mass distribution having a first rotational center; a set of plies coupled to the woven core and defining a second mass distribution; and a skin layer disposed externally of the set of plies and the woven core; wherein a combination of the first mass distribution and the second mass distribution collectively define a combined mass distribution that is closer to the balanced rotational center than the first rotational center.

[0079] A gas turbine engine as claimed in any preceding clause, wherein said combined mass distribution defines a combined centre of rotation aligned with said centre of equilibrium rotation.

[0080] A gas turbine engine as claimed in any preceding clause, wherein said woven core is made from a raw material defining said first mass distribution different from said equilibrium mass distribution.

[0081] A gas turbine engine according to any preceding clause, wherein the raw material is one of carbon or carbon fibre, glass or glass fibre, nylon, rayon, aramid fibre, nickel, titanium or a ceramic composite.

[0082] A gas turbine engine as claimed in any preceding clause, wherein said raw material comprises material properties defining said first mass distribution different from said equilibrium mass distribution.

[0083] The gas turbine engine of any preceding clause, wherein the at least one composite airfoil comprises a plurality of composite airfoils, and wherein the raw material defines a common first mass distribution among the plurality of composite airfoils, the common first mass distribution being generally different from the equilibrium mass distribution.

[0084] A gas turbine engine according to any preceding clause, wherein the combined centre of mass is aligned with the centre of balance rotation disposed along the engine centreline.

[0085] A gas turbine engine as in any preceding clause, wherein said combined mass distribution further defines a combined center of rotation aligned with said center of equilibrium rotation.

[0086] A gas turbine engine according to any preceding clause, wherein the combined centre of mass is aligned with the equilibrium centre of mass.

[0087] A gas turbine engine according to any preceding clause, wherein the first mass distribution defines a first center of mass corresponding to a first center of rotation arranged along the engine centerline, wherein the second mass distribution defines a second center of mass corresponding to a second center of rotation defined relative to the engine centerline, and wherein the first center of rotation is spaced apart from the second center of rotation.

[0088] A gas turbine engine as claimed in any preceding clause, wherein the woven core is a cured woven core defining a cured mass distribution having a cured centroid and a cured centre of rotation.

[0089] A gas turbine engine according to any preceding clause, wherein the difference between the cured mass distribution and the first mass distribution is the difference between the first centre of mass and the cured centre of mass, or the difference between the first centre of rotation and the cured centre of rotation.

[0090] The gas turbine engine of any preceding clause, wherein the at least one composite airfoil further comprises a pressure side and a suction side extending between a root and a tip defining a spanwise direction therebetween, and extending between a leading edge and a trailing edge defining a chordwise direction therebetween.

[0091] A gas turbine engine as claimed in any preceding clause, wherein said set of plies extends completely from said root to said tip.

[0092] A gas turbine engine according to any preceding clause, wherein said set of plies is provided on at least one of said pressure side and said suction side.

[0093] A gas turbine engine according to any preceding clause, wherein the set of plies is provided on both the pressure side and the suction side.

[0094] A gas turbine engine according to any preceding clause, wherein the woven core is a braided core.

[0095] A composite airfoil for a gas turbine engine, the composite airfoil defining a balanced mass distribution including a balanced center of mass aligned with a balanced rotational center, the composite airfoil comprising: a woven core defining a first mass distribution having a first rotational center; a set of plies coupled to the woven core and defining a second mass distribution; and a skin layer disposed exteriorly of the set of plies and the woven core; wherein the combination of the first mass distribution and the second mass distribution collectively define a combined mass distribution that is closer to the balanced rotational center than the first rotational center.

[0096] A gas turbine engine as claimed in any preceding clause, wherein said combined mass distribution defines a combined centre of rotation aligned with said centre of equilibrium rotation.

[0097] A gas turbine engine as claimed in any preceding clause, wherein said woven core is made from a raw material defining said first mass distribution different from said equilibrium mass distribution.

[0098] The gas turbine engine of any preceding clause, wherein the combined mass distribution defines a combined center of mass and a combined center of rotation, wherein the combined center of mass is aligned with the equilibrium center of rotation relative to the engine centerline.

[0099] A method of forming a composite airfoil having a balanced mass distribution, the balanced mass distribution defining a balanced center of mass corresponding to a balanced center of rotation disposed along an axis of rotation of a gas turbine engine, the method comprising: forming a woven core defining a first mass distribution; and applying a set of plies to the woven core, the set of plies defining a second mass distribution; wherein the woven core and the set of plies define a combined mass distribution, wherein the combined center of mass defines a combined center of rotation corresponding to the balanced center of rotation along the axis of rotation.

[0100] The method of any preceding clause, wherein forming the woven core further comprises forming the woven core from a raw material defining the first mass distribution.

[0101] A method according to any preceding clause, wherein the raw material is one of carbon or carbon fibre, glass or glass fibre, nylon, rayon, aramid fibre, nickel, titanium or a ceramic composite.

[0102] A method as in any preceding clause, wherein the raw material comprises material properties defining the first mass distribution that is different from the equilibrium mass distribution.

[0103] A method as in any preceding clause, further comprising measuring the woven core to determine the first mass distribution.

[0104] A method as in any preceding clause, further comprising comparing the first mass distribution to the equilibrium mass distribution to define an unbalanced mass distribution.

[0105] A method as in any preceding clause, wherein the second mass distribution is determined based on the unbalanced mass distribution.

[0106] The method of any preceding clause, wherein comparing the first mass distribution to the equilibrium mass distribution further comprises comparing a first center of mass defined by the first mass distribution to an equilibrium center of mass defined by the equilibrium mass distribution.

[0107] The method of any preceding clause, further comprising curing the woven core to define a cured first mass distribution as the first mass distribution.

[0108] The method of any preceding clause, further comprising curing the woven core and the set of plies to define a cured combined mass distribution as the combined mass distribution.

[0109] A method as in any preceding clause, wherein the solidified combined mass distribution defines the combined rotation center to align with the equilibrium rotation center.

[0110] A method of forming a group of composite airfoils, each composite airfoil in the group having a balanced mass distribution, the balanced mass distribution defining a balanced center of mass corresponding to a balanced center of rotation relative to a rotational axis, the method comprising: forming a tissue core from a raw material, wherein each woven core in the tissue core defines a first mass distribution; and applying a group of plies to each woven core in the tissue core, wherein each group of plies defines a second mass distribution; wherein the woven core and the group of plies of each composite airfoil in the group define a combined mass distribution, wherein the combined center of mass defines a combined center of rotation corresponding to the balanced center of rotation along the rotational axis.

[0111] A method as in any preceding clause, wherein said raw material defines a common first mass distribution among said tissue cores, said common first mass distribution being generally different from said equilibrium mass distribution of each composite airfoil in said set of airfoils.

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; as well as at least one composite airfoil disposed in one of the fan section, the compressor section, or the turbine section and rotatable about the engine centerline, the at least one composite airfoil having a balanced mass distribution defining a balanced center of mass aligned with a balanced center of rotation defined relative to the engine centerline, wherein the at least one composite airfoil comprises: a woven core defining a first mass distribution having a first center of rotation; a set of plies coupled to the woven core and defining a second mass distribution; and a skin layer disposed exteriorly of the set of plies and the woven core; The combination of the first mass distribution and the second mass distribution together defines a combined mass distribution that is closer to the equilibrium rotation center than to the first rotation center.

2. The gas turbine engine according to claim 1, wherein: in, The combined mass distribution defines a combined center of rotation aligned with the equilibrium center of rotation.

3. The gas turbine engine according to claim 1, wherein: in, The woven core is made of a raw material defining a first mass distribution that is different from the equilibrium mass distribution.

4. The gas turbine engine according to claim 3, characterized in that in, The raw material includes material properties defining the first mass distribution that is different from the equilibrium mass distribution.

5. The gas turbine engine according to claim 3, wherein: in, The at least one composite airfoil includes a plurality of composite airfoils, and wherein the raw material defines a common first mass distribution among the plurality of composite airfoils, the common first mass distribution being generally different from the equilibrium mass distribution.

6. The gas turbine engine according to claim 1, wherein: in, The combined mass distribution defines a combined center of mass and a combined center of rotation, wherein the combined center of mass is aligned with the equilibrium center of rotation relative to the engine centerline.

7. The gas turbine engine according to claim 6, characterized in that in, The combined rotation center is aligned with the balanced rotation center.

8. The gas turbine engine according to claim 6, wherein: in, The combined center of mass is aligned with the equilibrium center of mass.

9. The gas turbine engine according to claim 1, wherein: in, The first mass distribution defines a first center of mass corresponding to a first center of rotation relative to the engine centerline, wherein the second mass distribution defines a second center of mass corresponding to a second center of rotation relative to the engine centerline, and The first rotation center is spaced apart from the second rotation center.

10. The gas turbine engine according to claim 1, wherein: in, The woven core is a cured woven core defining a cured mass distribution having a cured centroid and a cured center of rotation.

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