Patent ID: 12203390

DETAILED DESCRIPTION

Aspects of the disclosure herein are directed to a composite airfoil assembly. For the purposes of illustration, the present disclosure will be described with respect to a turbine engine airfoil assembly, and more specifically a composite airfoil assembly within a fan section of the turbine engine. It will be understood, however, that aspects of the disclosure described herein are not so limited and can have general applicability within other engines or within other turbine engine portions. For example, aspects of the disclosure be applicable to composite airfoil assemblies in other engines or vehicles, and can also be used to provide benefits in industrial, commercial, and residential applications.

The composite airfoil assembly can be used at one or more locations within the turbine engine. For example, the composite airfoil assembly is suitable as a fan blade in a fan section of a turbine engine. Other locations, such as the compressor section and turbine section are contemplated. The composite airfoil assembly can be mounted in a variety of ways. One such mounting is securing the blades to a spinner of the fan section, directly, or via a pitch control assembly. Wherever the composite airfoil assembly is located, one suitable mounting is a disk that has complementary slots to receive the dovetail, with the slots circumferentially spaced about the periphery of the disk. The composite airfoil assembly and disk can collectively form a rotating assembly such that the composite airfoil assembly is a composite blade assembly.

As used herein, the term “upstream” refers to a direction that is opposite the fluid flow direction, and the term “downstream” refers to a direction that is in the same direction as the fluid flow. The term “fore” or “forward” can mean in front of something and “aft” or “rearward” can mean behind something. For example, when used in terms of fluid flow, fore/forward refers to an upstream direction and aft/rearward refers to a downstream direction.

Additionally, as used herein, the terms “radial” or “radially” refer to a direction away from a common center. For example, in the overall context of a turbine engine, radial refers to a direction along a ray extending between a center longitudinal axis of the engine and an outer engine circumference. Furthermore, as used herein, the term “set” or a “set” of elements can be any number of elements, including only one.

In addition, as used herein, the term “fluid” or iterations thereof can refer to any suitable fluid within the gas turbine engine at least a portion of the gas turbine engine is exposed to such as, but not limited to, combustion gases, ambient air, pressurized airflow, working airflow, or any combination thereof. It is also contemplated that the gas turbine engine can be other suitable turbine engine such as, but not limited to, a steam turbine engine or a supercritical carbon dioxide turbine engine. As a non-limiting example, the term “fluid” can refer to steam in a steam turbine engine, or to carbon dioxide in a supercritical carbon dioxide turbine engine.

All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, aft, etc.) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of aspects of the disclosure described herein. Connection references (e.g., attached, coupled, secured, fastened, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to one another. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary.

The term “composite,” as used herein is, is indicative of a component having two or more materials. A composite can be a combination of at least two or more metallic, non-metallic, or a combination of metallic and non-metallic elements or materials. Examples of a composite material can be, but not limited to, a polymer matrix composite (PMC), a ceramic matrix composite (CMC), a metal matrix composite (MMC), carbon fibers, a polymeric resin, a thermoplastic resin, bismaleimide (BMI) materials, polyimide materials, an epoxy resin, glass fibers, and silicon matrix materials.

As used herein, a “composite component” refers to a structure or a component including any suitable composite material. Composite components, such as a composite airfoil, can include several layers or plies of composite material. The layers or plies can vary in stiffness, material, and dimension to achieve the desired composite component or composite portion of a component having a predetermined weight, size, stiffness, and strength. One or more layers of adhesive can be used in forming or coupling composite components. Adhesives can include resin and phenolics, wherein the adhesive can require curing at elevated temperatures or other hardening techniques.

As used herein, “polymer matrix composite” or “PMC” refers to a class of materials. By way of example, a PMC material is defined in part by a prepreg, which is a reinforcement material pre-impregnated with a polymer matrix material, such as a thermoset resin or a thermoplastic resin. Non-limiting examples of processes for producing thermoplastic prepregs include hot melt pre-pregging in which the fiber reinforcement material is drawn through a molten bath of resin and powder pre-pregging in which a resin is deposited onto the fiber reinforcement material, by way of non-limiting example electrostatically, and then adhered to the fiber, by way of non-limiting example, in an oven or with the assistance of heated rollers. The prepregs can be in the form of unidirectional tapes or woven fabrics, which are then stacked on top of one another to create the number of stacked plies desired for the part.

In one non-limiting example of forming a composite component, multiple layers of prepreg can be stacked to a desired thickness and orientation for the composite component, and the resin can be subsequently cured and solidified to render the fiber-reinforced composite part. Resins for matrix materials of PMCs can be generally classified as thermosets or thermoplastics. Thermoplastic resins are generally categorized as polymers that can be repeatedly softened and flowed when heated and hardened when sufficiently cooled due to physical rather than chemical changes. Notable example classes of thermoplastic resins include nylons, thermoplastic polyesters, polyaryletherketones, and polycarbonate resins. Specific examples of high performance thermoplastic resins that have been contemplated for use in aerospace applications include, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyaryletherketone (PAEK), and polyphenylene sulfide (PPS). In contrast, once fully cured into a hard rigid solid, thermoset resins do not undergo significant softening when heated, but instead thermally decompose when sufficiently heated. Notable examples of thermoset resins include epoxy, bismaleimide (BMI), and polyimide resins.

In another non-limiting example, a woven or braided fabric can be used to form a composite component in addition or as an alternative to prepreg layering. One non-limiting example of a woven fabric can include dry carbon fibers woven together with thermoplastic polymer fibers or filaments. One non-limiting example of a braided architecture can include dry carbon fibers and thermoplastic polymer fibers braided together in multiple-strand arrangements. It is possible to tailor various properties of the composite part, such as the fiber volume, material strength, rigidity, impact resistance, or the like in some non-limiting examples, by selecting or tailoring the relative concentrations of the thermoplastic fibers and reinforcement fibers that have been woven or braided together. For instance, in one non-limiting example of a woven composite component having glass fibers, carbon fibers, and thermoplastic fibers, the carbon fiber concentration can be selected for providing material strength, the glass fiber concentration can be selected for enhanced impact resistance, which is a design characteristic for parts located near the inlet of the engine, and the thermoplastic fiber concentration can be selected for binding properties of the fibers in the woven fabric.

In still another non-limiting example, resin transfer molding (RTM) can be used to form a composite component in addition or as an alternative to prepreg, weaving, or braiding. RTM provides one example of an “out-of-autoclave” (OOA) process wherein the composite component can be formed and cured without need of an autoclave curing environment. Generally, RTM includes the application of dry fibers or matrix material to a mold or cavity. The dry fibers or matrix material can include prepreg, braided material, woven material, or any combination thereof. Placement or application of the dry fibers or matrix material can be manual or automated. Resin can be subsequently pumped into 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 are then cured and removed from the mold. The dry fibers or matrix material can also be contoured to shape the composite component or direct the resin. In certain examples where prepreg layups are used, the same resin used to form the prepreg layups can also be injected into the mold or cavity to form the composite component in a process known as “Same Qualified Resin Transfer Molding” (SQRTM). It is further contemplated that RTM can be vacuum-assisted in a process known as “Vacuum Assisted Resin Transfer Molding” (VARTM). In such a case, air within the mold can be removed as the resin is drawn into the mold, prior to heating or curing. Optionally, additional layers or reinforcing layers of a material differing from the dry fiber or matrix material can also be included or added prior to heating or curing. In some examples, post-curing processing can be performed on the composite component after removal from the mold.

As used herein, “ceramic matrix composite” or “CMC” refers to a class of materials with reinforcing fibers in a ceramic matrix. Generally, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of reinforcing fibers can 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 oxycarbides, silicon oxynitrides, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates such as mullite, or mixtures thereof), or mixtures thereof.

Some examples of ceramic matrix materials can 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 oxycarbides, silicon oxynitrides, 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., pyrophyllithe, wollastonite, mica, talc, kyanite, and montmorillonite) can also be included within the ceramic matrix.

Generally, particular CMCs can be referred to as their combination of type of fiber/type of matrix. For example, C/SiC for carbon-fiber-reinforced silicon carbide; SiC/SiC for silicon carbide-fiber-reinforced silicon carbide, SiC/SiN for silicon carbide fiber-reinforced silicon nitride, SiC/SiC—SiN for silicon carbide fiber-reinforced silicon carbide/silicon nitride matrix mixture, or the like. In other examples, the CMCs can be comprised 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.

In certain non-limiting examples, the reinforcing fibers may be bundled and/or coated prior to inclusion within the matrix. For example, bundles of the fibers may be formed as a reinforced tape, such as a unidirectional reinforced tape. A plurality of the tapes may be laid up together to form a preform component. The bundles of fibers may be impregnated with a slurry composition prior to forming the preform or after formation of the preform. The preform may then undergo thermal processing, and subsequent chemical processing to arrive at a component formed of a CMC material having a desired chemical composition. For example, the preform may undergo a cure or burn-out to yield a high char residue in the preform, and subsequent melt-infiltration with silicon, or a cure or pyrolysis to yield a silicon carbide matrix in the preform, and subsequent chemical vapor infiltration with silicon carbide. Additional steps may be taken to improve densification of the preform, either before or after chemical vapor infiltration, by injecting it with a liquid resin or polymer followed by a thermal processing step to fill the voids with silicon carbide. CMC material as used herein may be formed using any known or hereinafter developed methods including, but not limited to, melt infiltration, chemical vapor infiltration, polymer impregnation pyrolysis (PIP), or any combination thereof.

Such materials, along with certain monolithic ceramics (i.e., ceramic materials without a reinforcing material), are particularly suitable for higher temperature applications. Additionally, these ceramic materials are lightweight compared to superalloys, yet can still provide strength and durability to the component made therefrom. Therefore, such materials are currently being considered for many gas turbine components used in higher temperature sections of gas turbine engines, such as airfoils (e.g., turbines, and vanes), combustors, shrouds and other like components, that would benefit from the lighter-weight and higher temperature capability these materials can offer.

The term “metallic” as used herein is indicative of a material that includes metal such as, but not limited to, titanium, iron, aluminum, stainless steel, and nickel alloys. A metallic material or alloy can be a combination of at least two or more elements or materials, where at least one is a metal.

FIG.1is a schematic cross-sectional diagram of a turbine engine10for an aircraft. The turbine engine10has a generally longitudinally extending axis or centerline12extending forward14to aft16. The turbine engine10includes, in downstream serial flow relationship, a fan section18including a fan20, a compressor section22including a booster or low pressure (LP) compressor24and a high pressure (HP) compressor26, a combustion section28including a combustor30, a turbine section32including a HP turbine34, and a LP turbine36, and an exhaust section38.

The fan section18includes a fan casing40surrounding the fan20. The fan20includes a plurality of fan blades42disposed radially about the engine centerline12. The HP compressor26, the combustor30, and the HP turbine34form a core44of the turbine engine10, which generates combustion gases. The core44is surrounded by a core casing46, which can be coupled with the fan casing40.

A HP shaft or spool48disposed coaxially about the engine centerline12of the turbine engine10drivingly connects the HP turbine34to the HP compressor26. A LP shaft or spool50, which is disposed coaxially about the engine centerline12of the turbine engine10within the larger diameter annular HP spool48, drivingly connects the LP turbine36to the LP compressor24and fan20. The spools48,50are rotatable about the engine centerline and couple to a plurality of rotatable elements, which can collectively define a rotor51.

The LP compressor24and the HP compressor26respectively include a plurality of compressor stages52,54, in which a set of compressor blades56,58rotate relative to a corresponding set of static compressor vanes60,62to compress or pressurize the stream of fluid passing through the stage. In a single compressor stage52,54, multiple compressor blades56,58can be provided in a ring and can extend radially outward relative to the engine centerline12, from a blade platform to a blade tip, while the corresponding static compressor vanes60,62are positioned upstream of and adjacent to the rotating compressor blades56,58. It is noted that the number of blades, vanes, and compressor stages shown inFIG.1were selected for illustrative purposes only, and that other numbers are possible.

The compressor blades56,58for a stage of the compressor can be mounted to (or integral to) a disk61, which is mounted to the corresponding one of the HP and LP spools48,50. The static compressor vanes60,62for a stage of the compressor can be mounted to the core casing46in a circumferential arrangement.

The HP turbine34and the LP turbine36respectively include a plurality of turbine stages64,66, in which a set of turbine blades68,70are rotated relative to a corresponding set of static turbine vanes72,74, also referred to as a nozzle, to extract energy from the stream of fluid passing through the stage. In a single turbine stage64,66, multiple turbine blades68,70can be provided in a ring and can extend radially outward relative to the engine centerline12while the corresponding static turbine vanes72,74are positioned upstream of and adjacent to the rotating turbine blades68,70. It is noted that the number of blades, vanes, and turbine stages shown inFIG.1were selected for illustrative purposes only, and that other numbers are possible.

The turbine blades68,70for a stage of the turbine can be mounted to a disk71, which is mounted to the corresponding one of the HP and LP spools48,50. The turbine vanes72,74for a stage of the compressor can be mounted to the core casing46in a circumferential arrangement.

Complementary to the rotor portion, the stationary portions of the turbine engine10, such as the static vanes60,62,72,74among the compressor and turbine sections22,32are also referred to individually or collectively as a stator63. As such, the stator63can refer to the combination of non-rotating elements throughout the turbine engine10.

In operation, the airflow exiting the fan section18is split such that a portion of the airflow is channeled into the LP compressor24, which then supplies a pressurized airflow76to the HP compressor26, which further pressurizes the air. The pressurized airflow76from the HP compressor26is mixed with fuel in the combustor30and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine34, which drives the HP compressor26. The combustion gases are discharged into the LP turbine36, which extracts additional work to drive the LP compressor24, and the exhaust gas is ultimately discharged from the turbine engine10via the exhaust section38. The driving of the LP turbine36drives the LP spool50to rotate the fan20and the LP compressor24.

A portion of the pressurized airflow76can be drawn from the compressor section22as bleed air77. The bleed air77can be drawn from the pressurized airflow76and provided to engine components requiring cooling. The temperature of pressurized airflow76entering the combustor30is significantly increased above the bleed air temperature. The bleed air77may be used to reduce the temperature of the core components downstream of the combustor. The bleed air77can also be utilized by other systems.

A remaining portion of the airflow, referred to as a bypass airflow78, bypasses the LP compressor24and engine core44and exits the turbine engine10through a stationary vane row, and more particularly an outlet guide vane assembly80, comprising a plurality of airfoil guide vanes82, at a fan exhaust side84. More specifically, a circumferential row of radially extending airfoil guide vanes82are utilized adjacent the fan section18to exert some directional control of the bypass airflow78.

Some of the air supplied by the fan20can bypass the engine core44and be used for cooling of portions, especially hot portions, of the turbine engine10, and/or used to cool or power other aspects of the aircraft. In the context of a turbine engine, the hot portions of the engine are normally downstream of the combustor30, especially the turbine section32, with the HP turbine34being the hottest portion as it is directly downstream of the combustion section28. Other sources of cooling fluid can be, but are not limited to, fluid discharged from the LP compressor24or the HP compressor26.

FIG.2is a schematic perspective view of a disk90and a composite airfoil assembly100(also referred to herein as “airfoil assembly100”) suitable for use within the turbine engine10ofFIG.1. The disk90is suitable for use as the disk61,71(FIG.1) or any other disk, such as a disk within the fan section18of the turbine engine10in a non-limiting example. The airfoil assembly100can be rotating or non-rotating such that the airfoil assembly100can include at least one of the static compressor vanes60,62(FIG.1), the set of compressor blades56,58(FIG.1), the static turbine vanes72,74(FIG.1), the set of turbine blades68,70(FIG.1), or the plurality of fan blades42. In one non-limiting example, the airfoil assembly100can include a composite blade within the fan section18(FIG.1) and configured to rotate within the turbine engine10(FIG.1) at a rotational speed between 1000-2500 RPM during operation.

For reference purposes, a set of relative reference directions along with a coordinate system are shown inFIG.2and applied to the airfoil assembly100and the disk90. An axial direction A extends from forward to aft and is shown extending partially into the page. A radial direction R is shown extending perpendicular to the axial direction A. A circumferential direction C is defined circumferentially about the axial direction A. Put another way, the circumferential direction C can be defined as a ray extending locally and orthogonally from the radial direction R as shown.

The disk90can include a disk outer surface92. Multiple slots94can be provided in the disk outer surface92and arranged circumferentially about the disk90as shown. Each slot94can be configured to receive a corresponding airfoil assembly100. In addition, the disk90can be rotatable or stationary about an axis96. In an instance where the disk90is stationary, it will be appreciated that the disk90can be any suitable stationary portion of the turbine engine that the airfoil assembly100is couplable to, such as, but not limited to, a band, a shroud, a casing, or the like. In one non-limiting example, the axis96coincides with the engine centerline12(FIG.1). In another non-limiting example, the axis96is parallel to the engine centerline12. In still another non-limiting example, the axis96intersects or forms an angle with the engine centerline12.

In some implementations, the axial direction A can be coincident with the axis96. In such a case, it is understood that the radial direction R is orthogonal to the axis96, and the circumferential direction C extends circumferentially about the axis96. Furthermore, in some implementations, the axial direction A can also be coincident with the engine centerline12(FIG.1). In such a case, the radial direction R is orthogonal to the engine centerline12(FIG.1), and the circumferential direction C extends circumferentially about the turbine engine10relative to the engine centerline12.

The airfoil assembly100includes an airfoil110defining an airfoil interior106and having an exterior surface105. The exterior surface105extends axially between a leading edge111and a trailing edge112, and also extends radially between a root113and a tip114. In the example shown, the airfoil110also defines a pressure side115and a suction side116. In another non-limiting example, the airfoil110can be a symmetric airfoil such that the exterior surface105is axially symmetric.

In the example shown, the airfoil assembly100also includes a dovetail120extending from the root113of the airfoil110as shown. The dovetail120extends radially between a first end121and a second end122. The first end121defines a radially inner surface of the dovetail120. The second end122forms a transition between the dovetail120and the airfoil110. The dovetail120also defines a dovetail interior126as shown. The airfoil110and the dovetail120can also be integrally or unitarily formed with each other in some implementations.

The composite airfoil assembly100is assembled with the disk90by inserting at least a portion of the dovetail120axially through a respective slot94. The airfoil110extends radially outward from the slot94. In some implementations, the second end122coincides with the root113of the airfoil110such that the root113is aligned with the disk outer surface92.

The composite airfoil assembly100is held in place by frictional contact with the slot94or can be coupled to the slot94via any suitable coupling method such as, but not limited to, welding, adhesion, fastening, or the like. While only a single composite airfoil assembly100is illustrated, any number of composite airfoil assemblies100can be coupled to the disk90. As a non-limiting example, a plurality of composite airfoil assemblies100can be provided corresponding to a total number of slots94about the disk90.

Turning toFIG.3, the composite airfoil assembly100is shown in a schematic perspective view. An inner support structure130is provided within the airfoil interior106of the airfoil assembly100. The inner support structure130can be positioned within at least one of the airfoil110or the dovetail120. In the non-limiting example shown, the inner support structure130extends radially within both the airfoil110and the dovetail120.

The inner support structure130can include a plurality of cores140(shown in dashed line). The plurality of cores140can include one or more composite core materials. In some implementations, at least one core in the plurality of cores140can include intertwined fibers defining a three-dimensional core structure. Such intertwined fibers can include, but are not limited to, single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or combinations thereof, that form or define the three-dimensional core structure. For instance, in some implementations, fiber tows can be braided and subsequently interwoven to form the three-dimensional core structure. It is also contemplated that each core in the plurality of cores140can include such three-dimensional core structures as described above.

In the example shown, the plurality of cores140includes a first core140a, a second core140b, and a third core140c. It is understood that the plurality of cores140can include any number of cores, including four or more. In the non-limiting example shown, the first core140ais positioned within the dovetail120and extends radially into the airfoil110at the root113. The second core140bis positioned radially outward from the first core140aand extends along the leading edge111toward the tip114. The third core140cis positioned radially outward from the first core140a, and is also arranged axially with the second core140b, such that the third core140cextends along the trailing edge112toward the tip114.

A laminate overlay150covers over and surrounds the inner support structure130, including the first core140a, second core140b, and third core140c. In some implementations, the laminate overlay150defines the exterior surface105of the composite airfoil assembly100. In some implementations, the laminate overlay150can be at least partially covered by one or more additional layers defining the exterior surface105.

The laminate overlay150can be in the form of a composite skin. As used herein, a “skin” refers to a layer of material having multiple plies or layers of composite materials. The laminate overlay150can include multiple stacked composite plies formed by any suitable process, including at least one of pre-impregnated fibers in a polymer matrix, automated fiber placement (AFP), dry fiber placement (DFP), or tailored fiber placement (TFP) in non-limiting examples.

In this manner, the plurality of cores140and the laminate overlay150can each include composite materials with differing material structures. Some or all cores in the plurality of cores140can have corresponding three-dimensional core structures defined by intertwined fibers, such as a woven core structure or a braided core structure as described above. The laminate overlay150can include multiple plies arranged in a stack as described above. It is contemplated that a density of the laminate overlay150can be greater than a density of the three-dimensional structure of a core in the plurality of cores140. In a non-limiting example, a core in the plurality of cores140can have a three-dimensional core structure with a density between 0.2-1.6 g/cm3, and the laminate overlay150can have a density between 1.4-1.6 g/cm3.

Referring now toFIG.4, a schematic side view of the airfoil assembly100is shown. The inner support structure130is illustrated in solid line, and the laminate overlay150is illustrated in dashed line, including the airfoil110and the dovetail120.

In the example shown, the first core140ais radially spaced from each of the second core140band the third core140c, and the second core140bis axially spaced from the third core140c, though this need not be the case. It is also contemplated that at least some cores in the plurality of cores140can be in an abutting or physical-contact arrangement in some implementations.

The plurality of cores140can include cores having identical or differing geometric profiles. As shown, the first core140a, the second core140b, and the third core140cdefine a respective first core width141a, second core width141b, and third core width141calong the axial direction A. In the non-limiting example shown, an average value of the second core width141bis less than an average value of the first core width141a. In addition, in the non-limiting example shown, an average value of the third core width141cis less than the average value of the first core width141a. It is contemplated that each core in the plurality of cores140can have any suitable width, including a constant width or a non-constant width.

In addition, the first core140a, second core140b, and third core140ccan each define a respective first height142a, second height142b, and third height142calong the radial direction R. In the non-limiting example shown, an average value of the second height142bis larger than an average value of the first height142a. In addition, in the non-limiting example shown, an average value of the third height142cis larger than the average value of the first height142a. It is contemplated that each core in the plurality of cores140can have any suitable height, including a constant height or a non-constant height.

A set of pins160can also be provided in the inner support structure130. The set of pins160can be insertable into one or more cores in the plurality of cores140for maintaining relative arrangements or positioning, improving stability, or preventing delamination, in non-limiting examples. In the non-limiting example shown, the set of pins160includes pins inserted into each of the first, second, and third cores140a,140b,140c. Additionally or alternatively, the set of pins160can include a single pin extending through three or more cores in the plurality of cores140. Additionally or alternatively, the set of pins160can include multiple pins inserted into a single core in the plurality of cores140. Furthermore, while the set of pins160are schematically illustrated as being rectangular, it is understood that the set of pins160can have any suitable geometric profile including rounded, tapered, flanged, single-pointed end, dual-pointed ends, or the like. It is understood that the set of pins160can provide for securing or maintaining a spaced arrangement among the plurality of cores140in some examples, or maintaining an abutting arrangement among the plurality of cores140in some examples.

Still further, it is understood that additional pins not shown inFIG.4can nevertheless be provided in the airfoil assembly100. Such additional pins can extend in any suitable direction. Such additional pins can also be inserted into or positioned entirely within the laminate overlay150, spaced from the set of cores140, providing for increased stability or mitigating potential delamination of the laminate overlay150.

FIG.5illustrates a cross-sectional view of the airfoil assembly100along line V-V ofFIG.4. In this view, the inner support structure130is shown with the plurality of cores140, particularly the second core140band the third core140c, and with the laminate overlay150forming the exterior surface105.

A local spacing distance145can be defined between adjacent cores in the plurality of cores140. In the example shown, one local spacing distance145is illustrated between the second core140band the third core140c. It is contemplated that the laminate overlay150can at least partially fill the local spacing distance145. In the example shown, the laminate overlay150completely fills the local spacing distance145such that the second core140band third core140care each completely surrounded by the laminate overlay150. In some implementations, the laminate overlay150can partially fill the local spacing distance145such that a gap can be present between the second and third cores140b,140c. Additionally or alternatively, a resin material can be introduced into the local spacing distance145to form a resin-rich gap between the second and third cores140b,140c.

In addition, the second core140band the third core140care each illustrated as having a woven-fiber architecture, e.g., formed using woven-fiber plies, though this need not be the case. It is also contemplated that either or both of the second core140band the third core140ccan include a braided-fiber architecture, e.g., formed using braided-fiber plies, or a combination of woven-fiber plies stacked with braided-fiber plies, in non-limiting examples.

With general reference toFIGS.1-5, when forming the composite airfoil assembly100, at least some cores in the plurality of cores140can be formed by stacking woven-fiber plies or prepregs, braided-fiber plies or prepregs, or a combination thereof, into a desired core shape to form one or more precursors or layups. The precursor(s) are then cured and optionally shaped, using any suitable method, including by way of an RTM process as described above. The plurality of cores140can be subsequently arranged, positioned, or the like, including by way of the set of pins160in some examples, thereby forming the inner support structure130. In some implementations, resin can be applied between adjacent cores in the plurality of cores140to at least partially fill local spacing distance(s)145in the inner support structure130. The laminate overlay150can then be formed over the inner support structure130, including by way of RTM processes in some implementations, and the resulting component can be further cured or shaped to form the composite airfoil assembly100. In addition, the laminate overlay150can at least partially fill local spacing distance(s)145in the inner support structure130, including covering over a resin layer within the local spacing distance(s)145. Furthermore, in some implementations the laminate overlay150defines the exterior surface105of the composite airfoil assembly100as described above. Additionally or alternatively, an additional layer, cover, coating, overlay, or the like can be applied over the laminate overlay150and define the exterior surface105.

Referring now toFIG.6, another composite airfoil assembly200(also referred to herein as “airfoil assembly200”) is illustrated that is suitable for use with the turbine engine ofFIG.1and the disk ofFIG.2. The airfoil assembly200is similar to the airfoil assembly100. Therefore, the like parts of the airfoil assembly200will be described with like numerals increased by 100, with it being understood that the description of the like parts of the airfoil assembly100applies to the airfoil assembly200, except where noted.

The airfoil assembly200is shown in a schematic side view. The airfoil assembly200includes an airfoil210defining an airfoil interior206and having an exterior surface205(shown in dashed line). The exterior surface205extends axially between a leading edge211and a trailing edge212, and also extends radially between a root213and a tip214. The exterior surface205can additionally define a pressure side215and a suction side216(shown inFIG.7). The airfoil assembly200also includes a dovetail220extending from the root213and defining a dovetail interior226.

The airfoil assembly200includes an inner support structure230(shown in solid line) and a laminate overlay250defining the exterior surface205. The inner support structure230can include a plurality of cores240. The plurality of cores240can include one or more composite core materials. In some implementations, at least some cores in the plurality of cores240can include intertwined fibers defining a three-dimensional core structure. Such intertwined fibers can include single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or combinations thereof, in non-limiting examples. In some implementations, single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or the like can be woven together to form the three-dimensional core structure. In the example shown, the plurality of cores240includes a first core240a, a second core240b, and a third core240c. While not shown inFIG.6, it is contemplated that the inner support structure230can include a set of pins similar to the set of pins160(FIG.4).

One difference compared to the airfoil assembly100is that the first, second, and third cores240a.240b,240care radially aligned with the first core240aarranged within the dovetail210and the root213, the third core240carranged at the tip214, and the second core240bpositioned between the first and third cores240a,240c. Another difference compared to the airfoil assembly100is that one or more cores in the plurality of cores240can include a central sub-core, structure, or the like. In the example shown, the first core240aincludes a sub-core246(shown in dashed line).

Turning toFIG.7, a cross-sectional view of the airfoil assembly200illustrates additional details of the sub-core246, the first core240a, and the laminate overlay250. It is contemplated that the sub-core246can include a lightweight material, including a flexible foam or a rigid foam, including polystyrene foam in a non-limiting example. It is contemplated that the sub-core246can have a material density that is less than or equal to a density of the surrounding core material of the first core240a. In one non-limiting example, the first core240acan be formed by applying woven or braided plies over the sub-core246, and subsequently curing or shaping as described above. In another non-limiting example, the first core240acan be formed by weaving fibers, yarns, braids, tows, or the like in a three-dimensional manner about the sub-core246. In this manner, the first core240acan be built out to a large overall shape with a reduced weight due to the lightweight sub-core246. The laminate overlay250can be formed or applied over the first core240aand optionally define the exterior surface205as described above.

Referring now toFIG.8, another composite airfoil assembly300(also referred to herein as “airfoil assembly300”) is illustrated that is suitable for use with the turbine engine ofFIG.1and the disk ofFIG.2. The airfoil assembly300is similar to the airfoil assembly100ofFIGS.3-5and the airfoil assembly200ofFIGS.6and7. Therefore, the like parts of the airfoil assembly300will be described with like numerals further increased by 100, with it being understood that the description of the like parts of the airfoil assembly100,200applies to the airfoil assembly300, except where noted.

The airfoil assembly300is shown in a schematic side view. The airfoil assembly300includes an airfoil310defining an airfoil interior306and having an exterior surface305(shown in dashed line). The exterior surface305extends axially between a leading edge311and a trailing edge312, and also extends radially between a root313and a tip314. The airfoil assembly300also includes a dovetail320extending from the root313and defining a dovetail interior326.

The airfoil assembly300includes an inner support structure330(shown in solid line) and a laminate overlay350defining the exterior surface305. The inner support structure330can include a plurality of cores340. The plurality of cores340can include one or more composite core materials. In some implementations, at least some cores in the plurality of cores340can include intertwined fibers defining a three-dimensional core structure. Such intertwined fibers can include single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or combinations thereof, in non-limiting examples. In some implementations, single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or the like can be woven together to form the three-dimensional core structure.

In the example shown, the plurality of cores340includes a first core340aand a second core340bin a radially-spaced arrangement. A local spacing distance345is defined between the first core340aand the second core340bas shown. One difference compared to the airfoil assemblies100,200is that the plurality of cores340is fully contained within the airfoil310and does not extend into the dovetail320. It is contemplated that the laminate overlay350can be built up, stacked, or the like in the region of the dovetail320to fully define the dovetail320.

A set of pins360is provided with the inner support structure330. Another difference compared to the airfoil assemblies100,200is that the set of pins360includes multiple pins having differing insertion depths, alignments, or geometric profiles and inserted into the plurality of cores340. In the example shown, the set of pins360includes a first pin360a, a second pin360b, a third pin360c, a fourth pin360d, and a fifth pin360e. The first pin360a, second pin360b, third pin360c, fourth pin360d, and fifth pin360erespectively include a body364a,364b,364c.364d,364cextending between a respective first end361a,361b,361c,361d,361eand a respective second end362a,362b,362c,362d,362e(shown inFIGS.8-9).

In the illustrated example, the first and second pins360a.360bare positioned at least radially such that the first ends361a,361bare radially outward of the second ends362a,362b. The first ends361a,361bare inserted into the second core340b, and the second ends362a,362bare inserted into the first core340a. The third, fourth, and fifth pins360c.360d,360eare positioned at least circumferentially in the illustrated example.

At least some pins in the set of pins360can be unaligned with one another and extend in different directions within the inner support structure330. For instance, in the example shown, the first pin360aextends at least radially between the first core340aand the second core340b, and the fourth pin360dextends at least circumferentially within the second core340b. The first and fourth pins360a,360dcan be orthogonal to one another in some implementations. In addition, the second pin360bextends both radially and axially between the first and second cores340a,340bin the illustrated example, such that the first, second, and fourth pins360a,360b,360dare all mutually unaligned.

Furthermore, at least some pins in the set of pins360can include one or more flanges providing for control of insertion depth into the set of cores340. In the example shown, the first pin360aincludes flanges366a,366beach extending from the body364aand spaced from each of the first and second ends361a,362a. In this manner, the flanges366a,366bcan define a predetermined or fixed insertion depth into the corresponding core340a,340band thereby at least partially define the local spacing distance345as shown.

It is contemplated that the set of pins360can have any suitable geometric profile, including constant or variable body widths, and including symmetric or asymmetric bodies. In the illustrated example, a portion of the first pin360adefines a body width368athat is constant between the first end361aand the second end362a. Additionally, in the illustrated example, the second pin360bdefines a body width368bthat continuously increases from the first end361btoward the second end362b.

It is contemplated that a pin in the set of pins360can extend to the exterior surface305, or be fully inserted into the laminate overlay350and spaced from the exterior surface305, or be fully inserted within the set of cores340and spaced from the laminate overlay350, in non-limiting examples. In the example shown, the first and second ends361a,362aof the first pin360aare positioned within the respective second core340aand first core340aand spaced from the laminate overlay350. In addition, the fourth pin360dcan have a second end362d(shown in dashed line) that is located within the second core340b, and the fifth pin360ecan have a second end362ethat extends out of the second core340band into the laminate overlay350. It is understood that the set of pins360can extend in any direction through the airfoil assembly300, including perpendicularly through multiple stacked plies in the laminate overlay350or the set of cores340, or laterally along a ply in the laminate overlay350or the set of cores340, in non-limiting examples.

Turning toFIG.9, an enlarged cross-sectional view of the airfoil assembly300is shown along line IX-IX ofFIG.8. More specifically, the airfoil310is shown between the pressure side315and the suction side316and illustrates the pins360a,360c,360c,360d,360einserted into the second core340band laminate overlay350.

The set of pins360can include any suitable material, including metallic compositions, non-metallic compositions, a composite fiber material, or the like. For instance, in a non-limiting example, the first pin360aand the second pin360bcan each include a fibrous pin material. Such a fibrous pin material can include woven fibers, twisted fibers, braided fibers, knitted fibers, yarns, tows, or single strands, in non-limiting examples. More particularly, the second pin360bcan include a pin core365and a fiber overwrap367. In a non-limiting example, the pin core365can be metallic, and the fiber overwrap367can include fibers that are at least one of woven or spiral-wrapped about the pin core365. In a non-limiting example, the fiber overwrap367can include at least one of glass fibers or a composite fiber material. In some examples, prepregs can be utilized to form the composite fiber overwrap367. Regardless of the formation method used, the composite fiber overwrap367can be built up to form the second pin360bhaving a desired width or geometric profile. In this manner, the set of pins360can include pins with unitary bodies or layered bodies using single or multiple materials.

As described above, the first pin360aand second pin360bare inserted into the set of cores340and are each spaced from the laminate overlay350. In addition, the third pin360cextends at least circumferentially through the second core340bwith the first end361cextending to the exterior surface305and with the second end362clocated within the laminate overlay350. The fourth pin360dand the fifth pin360ealso extend at least circumferentially through the second core340b. Both ends361d,362dof the fourth pin360d, as well as the first end361eof the fifth pin360e, are positioned within the laminate overlay350and spaced from the exterior surface305. The second end362eof the fifth pin360eextends through the laminate overlay350to the exterior surface305.

In this manner, the inner support structure330can include the set of pins360extending into or through the set of cores340, providing for relative positioning or arrangement of the set of cores340prior to application of the laminate overlay350, and also providing for improved stability of the airfoil assembly300in operation.

Referring now toFIG.10, another composite airfoil assembly400(also referred to herein as “airfoil assembly400”) is illustrated that is suitable for use with the turbine engine ofFIG.1and the disk ofFIG.2. The airfoil assembly400is similar to the airfoil assembly100ofFIGS.3-5, the airfoil assembly200ofFIGS.6and7and the airfoil assembly300ofFIGS.8and9. Therefore, the like parts of the airfoil assembly400will be described with like numerals further increased by 100, with it being understood that the description of the like parts of the airfoil assemblies100,200,300applies to the airfoil assembly400, except where noted.

The airfoil assembly400is shown in a schematic side view. The airfoil assembly400includes an airfoil410defining an airfoil interior406and having an exterior surface405(shown in dashed line). The exterior surface405extends axially between a leading edge411and a trailing edge412, and also extends radially between a root413and a tip414. The airfoil assembly400also includes a dovetail420extending from the root413and defining a dovetail interior426.

The airfoil assembly400includes an inner support structure430(shown in solid line) and a laminate overlay450defining the exterior surface405. The inner support structure430can include a plurality of cores440. The plurality of cores440can include one or more composite core materials. In some implementations, at least some cores in the plurality of cores440can include intertwined fibers defining a three-dimensional core structure. Such intertwined fibers can include single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or combinations thereof, in non-limiting examples. In some implementations, single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or the like can be woven together to form the three-dimensional core structure.

In the example shown, the plurality of cores440includes a first core440a, a second core440b, and a third core440cin radial alignment. The first core440acan at least partially form the dovetail420and the root413. The third core440ccan at least partially form the tip414. The third core440ccan also include a sub-core446similar to the sub-core246(FIG.7). The sub-core446can include a lightweight material, including a rigid foam or a flexible foam in some non-limiting examples.

A set of pins460can be provided in the inner support structure430. In the example shown, the set of pins460includes a first pin460a, a second pin460b, and a third pin460c. The first pin460acan extend between and couple the second core440bto the third core440c. The third pin460ccan extend between and couple the first core440ato the second core440b. One difference compared to the airfoil assemblies100,200,300is that the second pin460bcan extend through three cores. More specifically, the second pin460bincludes a first end461bwithin the third core440c, extends fully through the second core440b, and includes a second end462bwithin the first core440a. In this manner, at least one pin in the set of pins460can extend between and connect at least a first core, a second core, and a third core.

In the example shown, the second pin460balso includes a flange466spaced from the first end461b. The flange466defines an insertion depth469into the third core440c. Another difference compared to the airfoil assemblies100,200,300is that the second pin460bcan extend into the sub-core446. In particular, the first end461bof the second pin460bis positioned within the sub-core446in the non-limiting example shown. It is understood that the insertion depth469can be selected, tailored, or the like to position the second pin460bwithin or through any suitable portion of the inner support structure430, including extending fully through the sub-core446in some implementations.

Another difference compared to the airfoil assemblies100,200,300is that the airfoil assembly400can include a cap or shield470over a portion of the laminate overlay450and define the leading edge411. Referring now toFIG.11, a cross-sectional view of the airfoil assembly400illustrates that the shield470can extend axially along the laminate overlay450and define at least a portion of the exterior surface405. In some non-limiting examples, the shield470can include a metallic material, a composite material, or a combination thereof. In some implementations the shield470can also include a single body or multiple discrete bodies that are coupled, bonded, or the like to the laminate overlay450. In this manner, the shield470can provide for increased strength or durability at the leading edge411.

Another difference compared to the airfoil assemblies100,200,300is that the airfoil410can be in the form of a symmetric airfoil, wherein the exterior surface405does not form a pressure side relative to a suction side. It is understood that in some implementations, the airfoil410can include pressure and suction sides.

In the illustrated example, the sub-core446includes a foam material and is surrounded by the three-dimensional core structure of the third core440c. The laminate overlay450surrounds the third core440cand defines a portion of the exterior surface405. The shield470defines the leading edge411as described above, and smoothly transitions to the laminate overlay450.

Referring now toFIG.12, one exemplary woven component500is shown that can be utilized in any or all of the airfoil assemblies100,200,300,400ofFIGS.3-11, respectively. For instance, the woven component500can at least partially form one or more cores in the plurality of cores140,240,340,440.

A coordinate system is provided for reference and includes a horizontal axis denoted ‘X,’ a vertical axis denoted ‘Y,’ and a third axis denoted ‘Z’ extending out of the page as shown. It will be understood that any of the axes X, Y, Z can align with the axial direction A, the radial direction R, or the circumferential direction C described above.

In the example shown, the woven component500defines a first side501vertically spaced from a second side502. A component thickness505is defined between the first and second sides501,502. In some non-limiting examples, the component thickness505can be between 0.1-2 inches, or between 0.5-1 inch, or between 1-2 inches.

The woven component500can have a three-dimensional woven structure. More specifically, the woven component500can be formed by a three-dimensional weaving process wherein the component thickness505is built up during weaving of warp fibers510, weft fibers520, and transverse fibers530. Such a weaving process can utilize a jacquard loom in some implementations. In this manner, the woven component500can be formed to near net shape without need of stacking plies to build up component thickness.

As shown, the woven component500is illustrated with exaggerated spacing between the warp fibers510, weft fibers520, and transverse fibers530for visual clarity, and it will be understood that a spacing distance between adjacent fibers in the woven component500can be any suitable size, including a tightly-woven configuration with adjacent fibers abutting one another, or a loose-weave configuration with adjacent fibers spaced or lofted from one another. It will also be understood that the warp fibers510, weft fibers520, or transverse fibers530can include single-strand fibers, fiber tows, woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, or the like, or combinations thereof.

The warp fibers510extend out of the page along the Z-axis. In the non-limiting example shown, the warp fibers510are oriented to form vertical columns525between the first side501and the second side502, with adjacent columns525being vertically offset in a staggered arrangement, though this need not be the case. In some non-limiting examples, the warp fibers510can form aligned columns, or have a non-symmetric or irregular arrangement or spacing through the woven component500, or the like.

The weft fibers520extend horizontally and are woven through the warp fibers510, with each weft fiber520alternating vertically above and below each successive warp fiber510as shown. In addition, in the example shown, adjacent weft fibers520are oppositely woven about each warp fiber510. In this manner, each warp fiber510can be vertically positioned between two adjacent weft fibers520.

The transverse fibers530are woven through the warp fibers510as well as the weft fibers520. As shown, the transverse fibers530are aligned along the Z-axis and woven vertically about each column525of warp fibers510, extending through all weft fibers520between the first side501in a through-thickness arrangement, though this need not be the case. In some non-limiting examples, the transverse fibers530can be woven vertically through portions of columns525such that they do not extend to either or both of the first side501or second side502, or the transverse fibers520can have an irregular distribution through the woven component500, or the like.

In this manner, the woven component500can include fibers woven in a three-dimensional manner and having a constant or non-constant fiber spacing, pattern, or the like. Such an arrangement can provide for tailoring of fiber densities, such as a constant or variable fiber density, in different portions of the woven component500. Such tailoring of fiber densities can provide for tailoring of material properties including material strength, torsion, stiffness, fatigue endurance, weight, or the like.

Turning now toFIG.13, a flowchart illustrates a method600of forming a composite airfoil assembly, such as the composite airfoil assembly100,200,300,400ofFIGS.3-11, respectively. The method600includes at602forming an inner support structure, such as the inner support structure130,230,330,340, with at least a first core and a second core, such as the first core140a,240a,340a,440a, or the second core140b,240b,340b,440b, each having a core material with at least one of fibers, yarns, braids, or tows.

In some implementations, forming the inner support structure at602includes intertwining the core material, such as fibers, yarns, braids, tows, or the like, to define a three-dimensional core structure for at least one of the first core or the second core. Additionally or alternatively, forming the inner support structure at602includes weaving fibers, yarns, tows, braids, or the like by a three-dimensional weaving process to define a three-dimensional core structure for at least one of the first core or the second core. Additionally or alternatively, forming the inner support structure at602includes weaving three sets of core materials, such as fibers, yarns, braids, tows, or the like, along corresponding three different directions to define a three-dimensionally-woven core structure for at least one of the first core or the second core.

Additionally or alternatively, forming the inner support structure at602includes forming at least one of the first core or the second core about a sub-core. Additionally or alternatively, forming the inner support structure at602includes positioning at least one of the first core or the second core to at least partially form a dovetail, a root, or a tip of the composite airfoil assembly.

Additionally or alternatively, forming the inner support structure at602includes inserting at least one pin, such as the set of pins460, into the first core and the second core, thereby connecting the first core to the second core. Additionally or alternatively, forming the inner support structure at602includes defining a spacing distance between the first core and the second core via the at least one pin. Additionally or alternatively, forming the inner support structure at602includes inserting the at least one pin into a sub-core within at least one of the first core or the second core. Additionally or alternatively, forming the inner support structure at602includes forming a composite pin by applying a composite material over a metallic pin core.

The method600also includes at604applying a laminate overlay, such as the laminate overlay150,250,350,450, to surround at least a portion of the inner support structure. In some implementations, applying the laminate overlay at604also includes applying multiple stacked plies over the inner support structure. Additionally or alternatively, applying the laminate overlay at604includes forming an exterior surface of the composite airfoil assembly. Additionally or alternatively, applying the laminate overlay at604includes at least partially filling a spacing distance, such as the local spacing distance145,345, between the first core and the second core with the laminate overlay.

Optionally, the method600can include at least partially filling a spacing distance, such as the local spacing distance145,345, between the first core and the second core with a resin material. Optionally, applying the laminate overlay at604includes covering over the resin material with the laminate overlay.

With general reference toFIGS.1-13, it is understood that aspects of the disclosure can be mixed, combined, or the like to form various composite airfoil assemblies suitable for use in the turbine engine10(FIG.1). Some additional examples will be described below, with it being understood that such examples are illustrative and do not limit the disclosure in any way.

In one exemplary implementation, an airfoil assembly can include an airfoil defining an airfoil interior and a dovetail defining a dovetail interior as described above. The airfoil assembly can include an inner support structure with multiple cores covered with a laminate overlay as described above. At least one of the multiple cores can be positioned within the airfoil interior alone, within the dovetail interior alone, within both of the airfoil interior and the dovetail interior. At least one of the multiple cores can be formed with intertwined fibers defining a three-dimensional core structure as described above. Optionally, the three-dimensional core structure can have a smaller density compared to the laminate overlay. Optionally, the inner support structure can include at least one pin connecting at least some of the multiple cores together. Optionally, at least one of the multiple cores can include the three-dimensional core structure as well as a sub-core with a different material composition compared to that of the surrounding three-dimensional core structure. Optionally, the sub-core can include a foam material. Optionally, the sub-core can have a smaller density compared to the three-dimensional core structure. Optionally, one of the multiple cores can include a shield forming the leading edge. Optionally, the shield, the sub-core, and the at least one pin can each be provided in a single, common core of the inner support structure.

In another exemplary implementation, an airfoil assembly can include an airfoil defining an airfoil interior and a dovetail defining a dovetail interior as described above. The airfoil assembly can include an inner support structure with multiple cores covered with a laminate overlay as described above. At least one of the multiple cores can be positioned within the airfoil interior alone, within the dovetail interior alone, within both of the airfoil interior and the dovetail interior. At least one of the multiple cores can be formed with a composite core material as described above. The inner support structure can include at least one pin connecting two cores together. The at least one pin can include a composite pin material. Optionally, the at least one pin can include a pin core with a composite overwrap as described above. Optionally, at least one of the two cores connected by the at least one pin can be formed with intertwined fibers defining a three-dimensional core structure as described above.

The described aspects of the present disclosure provide for a variety of benefits. The use of composite materials provides for a lighter airfoil assembly without sacrificing performance of the airfoil assembly when compared to a non-composite (e.g., cast) airfoil assembly. In other words, the materials used for the composite airfoil assembly are lighter than the materials used for the non-composite airfoil assembly and do not sacrifice the ability to perform as intended within the turbine engine. The decreased weight of the airfoil assembly, in turn, means an increased efficiency of the turbine engine when compared to a conventional turbine engine including non-composite airfoil assemblies.

Another benefit is that the use of multiple cores formed with intertwined fibers in a three-dimensional architecture provides for improved durability and material strength across multiple stress and strain directions in operation. The multiple cores additionally provide for a flexible, rearrangeable inner support structure suitable for a variety of blade architectures, which decreases assembly times and increases process efficiency during production.

Another benefit is that the use of a further-lightweight sub-core, as compared to the surrounding composite material in the three-dimensional core structure, provides for an even more lightweight airfoil assembly with additional engine efficiency and performance benefits. The lightweight sub-cores also provide for local inclusion of other strengthening components in the airfoil assembly, such as a shield as described above, while maintaining an overall decreased weight in the airfoil assembly compared to conventional turbine engine airfoil assemblies.

Still another benefit is that the use of fibrous-material pins to connect multiple cores in the inner support structure provides for flexibility in design and reduced production and assembly times, including by way of flanged pins forming predetermined insertion depths into each core. In addition, the use of pins with a pin core and fibrous overwrap provides for added component durability, such as by way of metallic pin cores, while maintaining weight reductions compared to traditional pins. The fibrous overwrap provides additional insulation or material protection, such as preventing oxidation, corrosion, or other material reactions of the inner support structure cores or the pin core, including preventing material reactions that may occur between the inner support structure cores and the pin core.

To the extent not already described, the different features and structures of the various embodiments can be used in combination, or in substitution with each other as desired. That one feature is not illustrated in all of the embodiments is not meant to be construed that it cannot be so illustrated, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. All combinations or permutations of features described herein are covered by this disclosure.

This written description uses examples to describe aspects of the disclosure described herein, including the best mode, and also to enable any person skilled in the art to practice aspects of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of aspects of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

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

A composite airfoil assembly for a turbine engine, comprising: an airfoil defining an airfoil interior and having an exterior surface extending axially between a leading edge and a trailing edge and extending radially between a root and a tip; a dovetail extending from the root and defining a dovetail interior; an inner support structure at least partially located within the airfoil interior and comprising a plurality of cores, with each core in the plurality of cores comprising intertwined fibers defining a three-dimensional core structure; and a laminate overlay surrounding at least a portion of the inner support structure and at least partially defining the exterior surface.

A composite airfoil assembly for a turbine engine, comprising: an airfoil defining an airfoil interior and having an exterior surface extending axially between a leading edge and a trailing edge and extending radially between a root and a tip; an inner support structure at least partially located within the airfoil interior and comprising a first core and a second core in radial alignment, with each of the first core and the second core comprising intertwined fibers defining a three-dimensional core structure; and a laminate overlay surrounding at least a portion of the inner support structure.

A composite airfoil assembly for a turbine engine, comprising: an airfoil defining an airfoil interior and having an exterior surface extending axially between a leading edge and a trailing edge and extending radially between a root and a tip; a dovetail extending from the root and defining a dovetail interior; an inner support structure, comprising: a first core and a second core each comprising a composite core material, with at least one of the first core or the second core positioned at least partially within at least one of the airfoil interior or the dovetail interior; and at least one pin extending between and connecting the first core to the second core and comprising a fibrous pin material; and a laminate overlay surrounding at least a portion of the inner support structure and at least partially defining the exterior surface.

A composite airfoil assembly for a turbine engine, comprising: an airfoil defining an airfoil interior and having an exterior surface extending axially between a leading edge and a trailing edge and extending radially between a root and a tip; an inner support structure at least partially located within the airfoil interior, the inner support structure comprising a first core and a second core each comprising a composite core material, and at least one pin extending between and connecting the first core to the second core, the at least one pin comprising a pin core with a fiber overwrap; and a laminate overlay surrounding at least a portion of the inner support structure and at least partially defining the exterior surface.

The composite airfoil assembly of any preceding clause, wherein the plurality of cores comprises a first core and a second core spaced at least radially from the first core.

The composite airfoil assembly of any preceding clause, wherein the plurality of cores further comprises a third core arranged at least one of axially or radially relative to the second core.

The composite airfoil assembly of any preceding clause, wherein the third core is positioned radially outward from the second core and at least partially defines a tip of the composite airfoil assembly.

The composite airfoil assembly of any preceding clause, further comprising a local spacing distance defined between two cores in the plurality of cores, with the local spacing distance at least partially filled by the laminate overlay.

The composite airfoil assembly of any preceding clause, wherein one core in the plurality of cores is positioned at least partially within the airfoil interior, and another core in the plurality of cores is positioned at least partially within the dovetail interior.

The composite airfoil assembly of any preceding clause, wherein the inner support structure comprises a first core defining a first width and a second core defining a second width less than the first width.

The composite airfoil assembly of any preceding clause, wherein the intertwined fibers comprise at least one of woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, tows, or single strands, and wherein the laminate overlay comprises multiple plies formed by at least one of pre-impregnated fibers in a polymer matrix, automated fiber placement, dry fiber placement, or tailored fiber placement.

The composite airfoil assembly of any preceding clause, wherein a core in the plurality of cores comprises a foam sub-core surrounded by the three-dimensional core structure defined by the intertwined fibers.

The composite airfoil assembly of any preceding clause, wherein a density of the laminate overlay is greater than the density of the three-dimensional core structure.

The composite airfoil assembly of any preceding clause, further comprising a dovetail extending from the root and defining a dovetail interior, wherein the first core is positioned at least partially within the dovetail interior, and the second core is positioned at least partially within the airfoil interior.

The composite airfoil assembly of any preceding clause, wherein the inner support structure further comprises a third core arranged at least one of axially or radially with the second core.

The composite airfoil assembly of any preceding clause, wherein the third core is positioned radially outward from the second core.

The composite airfoil assembly of any preceding clause, wherein the third core at least partially defines a tip of the composite airfoil assembly.

The composite airfoil assembly of any preceding clause, further comprising a local spacing distance defined between two of the first core, the second core, or the third core, with the local spacing distance at least partially filled by the laminate overlay.

The composite airfoil assembly of any preceding clause, wherein the intertwined fibers comprise at least one of woven fibers, braided fibers, twisted fibers, knitted fibers, yarns, tows, or single strands, and wherein the laminate overlay comprises multiple plies formed by at least one of pre-impregnated fibers in a polymer matrix, automated fiber placement, dry fiber placement, or tailored fiber placement.

The composite airfoil assembly of any preceding clause, wherein at least one of the first core or the second core comprises a foam sub-core surrounded by the three-dimensional core structure.

The composite airfoil assembly of any preceding clause, wherein a density of the three-dimensional core structure is greater than a density of the foam sub-core.

The composite airfoil assembly of any preceding clause, wherein a density of the laminate overlay is greater than the density of the three-dimensional core structure.

The composite airfoil assembly of any preceding clause, further comprising a shield covering a portion of the laminate overlay and defining the leading edge.

The composite airfoil assembly of any preceding clause, wherein the at least one pin defines a local spacing distance between the first core and the second core.

The composite airfoil assembly of any preceding clause, wherein the local spacing distance is at least partially filled by the laminate overlay.

The composite airfoil assembly of any preceding clause, wherein the fibrous pin material comprises at least one of fiberglass or a fiber composite material.

The composite airfoil assembly of any preceding clause, wherein the at least one pin further comprises a body extending between a first end and a second end, and a flange extending from the body to define an insertion depth into at least one of the first core or the second core.

The composite airfoil assembly of any preceding clause, wherein the flange is spaced from the first and second ends.

The composite airfoil assembly of any preceding clause, wherein at least a portion of the body defines a width that increases from the first end toward the second end.

The composite airfoil assembly of any preceding clause, wherein at least one of the first core or the second core comprises a sub-core.

The composite airfoil assembly of any preceding clause, wherein the at least one pin extends into the sub-core.

The composite airfoil assembly of any preceding clause, wherein the sub-core comprises a foam material.

The composite airfoil assembly of any preceding clause, wherein the at least one pin comprises a first pin extending at least radially between the first core and the second core.

The composite airfoil assembly of any preceding clause, wherein the at least one pin further comprises a second pin extending at least within the second core and unaligned with the first pin.

The composite airfoil assembly of any preceding clause, wherein the inner support structure further comprises a third core, with the at least one pin extending between and connecting the first core, the second core, and the third core.

The composite airfoil assembly of any preceding clause, wherein the fiber overwrap comprises fiberglass wrapped about the pin core.

The composite airfoil assembly of any preceding clause, wherein the at least one pin further comprises a body extending between a first end and a second end, and a flange extending from the body to define an insertion depth into at least one of the first core or the second core.

The composite airfoil assembly of any preceding clause, wherein the flange is spaced from each of the first and second ends.

The composite airfoil assembly of any preceding clause, wherein at least a portion of the body defines a width that increases from the first end toward the second end.

The composite airfoil assembly of any preceding clause, wherein at least one of the first core or the second core comprises a sub-core.

The composite airfoil assembly of any preceding clause, wherein the sub-core comprises a foam material.

The composite airfoil assembly of any preceding clause, wherein the at least one pin extends into the sub-core.

The composite airfoil assembly of any preceding clause, wherein the at least one pin comprises a first pin extending at least radially between the first core and the second core.

The composite airfoil assembly of any preceding clause, wherein the at least one pin further comprises a second pin extending at least within the second core and unaligned with the first pin.

The composite airfoil assembly of any preceding clause, wherein the composite airfoil assembly comprises a composite blade configured to rotate within the turbine engine at a rotational speed between 1000-2500 RPM.

The composite airfoil assembly of any preceding clause, wherein the exterior surface of the airfoil defines a pressure side relative to a suction side.

The composite airfoil assembly of any preceding clause, wherein the exterior surface of the airfoil defines a symmetric airfoil profile.

The composite airfoil assembly of any preceding clause, wherein the first core is positioned at least partially within the dovetail interior.

The composite airfoil assembly of any preceding clause, wherein the shield comprises a metallic material.

The composite airfoil assembly of any preceding clause, wherein the inner support structure further comprises a third core, with the at least one pin extending between and connecting at least two of the first core, the second core, and the third core.

The composite airfoil assembly of any preceding clause, wherein the fibrous pin material comprises at least one of glass fibers or a composite fiber material.

The composite airfoil assembly of any preceding clause, wherein the fiber overwrap comprises fibers that are at least one of spiral-wrapped or braided about the pin core.

A method of forming a composite airfoil assembly, comprising: forming an inner support structure with at least a first core and a second core each having a core material with at least one of fibers, yarns, braids, or tows, and applying a laminate overlay to surround at least a portion of the inner support structure.

The method of any preceding clause, wherein forming the inner support structure comprises intertwining the core material to define a three-dimensional core structure for at least one of the first core or the second core.

The method of any preceding clause, wherein forming the inner support structure comprises weaving the core material by a three-dimensional weaving process to define a three-dimensional core structure for at least one of the first core or the second core.

The method of any preceding clause, wherein forming the inner support structure comprises weaving three sets of core materials along corresponding three different directions to define a three-dimensionally-woven core structure for at least one of the first core or the second core.

The method of any preceding clause, wherein forming the inner support structure comprises forming at least one of the first core or the second core about a sub-core.

The method of any preceding clause, wherein forming the inner support structure comprises positioning at least one of the first core or the second core to at least partially form a dovetail, a root, or a tip of the composite airfoil assembly.

The method of any preceding clause, wherein forming the inner support structure comprises inserting at least one pin into the first core and the second core, thereby connecting the first core to the second core.

The method of any preceding clause, wherein forming the inner support structure comprises defining a spacing distance between the first core and the second core via the at least one pin.

The method of any preceding clause, wherein forming the inner support structure comprises inserting the at least one pin into a sub-core within at least one of the first core or the second core.

The method of any preceding clause, wherein forming the inner support structure comprises forming a composite pin by applying a composite material over a metallic pin core.

The method of any preceding clause, wherein applying the laminate overlay comprises applying multiple stacked plies over the inner support structure.

The method of any preceding clause, wherein applying the laminate overlay comprises forming an exterior surface of the composite airfoil assembly.

The method of any preceding clause, wherein applying the laminate overlay comprises at least partially filling a spacing distance between the first core and the second core with the laminate overlay.

The method of any preceding clause, further comprising at least partially filling a spacing distance between the first core and the second core with a resin material.

The method of any preceding clause, wherein applying the laminate overlay comprises covering over the resin material with the laminate overlay.