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EP-4549146-B1 - PRE-SHAPED SPACE FILLERS FOR SMALL CROSS SECTION FEATURES

EP4549146B1EP 4549146 B1EP4549146 B1EP 4549146B1EP-4549146-B1

Inventors

  • READ, Kathryn S.
  • ENOS, Shaun M.
  • FERNANDEZ, Robin H.
  • LILES, HOWARD J.
  • CAMPBELL, CHRISTIAN X.
  • SURACE, RAYMOND
  • RIEHL, JOHN D.
  • LOWERY, MORGAN
  • ROSENFELD, PETER J.

Dates

Publication Date
20260513
Application Date
20241024

Claims (15)

  1. A method of fabricating a variable geometry space filling insert (12) for a ceramic matrix composite component, the method comprising: arranging a plurality of fiber bodies (26A; 26B; 26C; 26D) into a preform insert (12A; 12B; 12C; 12D); applying a polymer binder to the plurality of fiber bodies (26A; 26B; 26C; 26D); trimming at least a first subset of the plurality of fiber bodies (26A; 26B; 26C; 26D) such that each of the first subset of fiber bodies (26A; 26B; 26C; 26D) is shorter than at least a second subset of fiber bodies (26A; 26B; 26C; 26D); and shaping the insert (12) with a forming tool to form a shaped insert (12).
  2. The method of claim 1, wherein each of the plurality of fiber bodies (26A; 26B; 26C; 26D) is formed from silicon carbide.
  3. The method of claim 1 or 2, wherein each of the plurality of fiber bodies (26A; 26B; 26C; 26D) is a silicon carbide tow or a strand of braided tows.
  4. The method of any preceding claim, further comprising incorporating a plurality of PVA yarns (30D) into the preform insert (12D).
  5. The method of any preceding claim, further comprising wrapping a fabric sheath (28C; 28D) around the plurality of fiber bodies (26C; 26D), wherein, optionally, the fabric sheath (28C; 28D) comprises silicon carbide.
  6. The method of any preceding claim, wherein the polymer binder comprises one of PVA and PVB.
  7. The method of any preceding claim, wherein the polymer binder comprises silicon carbide particles.
  8. The method of any preceding claim, further comprising: trimming a third subset of the plurality of fiber bodies (26A; 26B; 26C; 26D) such that each of the third subset of fiber bodies (26A; 26B; 26C; 26D) is shorter than the first subset and the second subset of fiber bodies (26A; 26B; 26C; 26D); and/or stabilizing the preform insert (12A; 12B; 12C; 12D) in the forming tool using one or a combination of mechanical compression, vacuum, vacuum compression, and heat.
  9. A method of forming a ceramic matrix composite component, the method comprising: fabricating a variable geometry space filling insert (12) using the method of any preceding claim; incorporating the insert (12) into a preform (10); and densifying the preform (10) with a ceramic matrix, wherein the step of densifying the preform (10) optionally comprises at least one of: chemical vapor infiltration, polymer infiltration and pyrolysis, melt infiltration, and slurry infiltration.
  10. A variable geometry space filling insert (12) for use in a ceramic matrix composite component, the insert (12) comprising: a plurality of fiber bodies (26A; 26B; 26C; 26D) in a bundle, the bundle comprising: a first subset of fiber bodies (26A; 26B; 26C; 26D); and a second subset of fiber bodies (26A; 26B; 26C; 26D), each being longer than each of the first subset of fiber bodies (26A; 26B; 26C; 26D).
  11. The insert (12) of claim 10, wherein each of the plurality of fiber bodies (26A; 26B; 26C; 26D) is a silicon carbide tow or a strand of braided tows.
  12. The insert (12) of claim 10 or 11, wherein the bundle further comprises a plurality of PVA yarns (30D).
  13. The insert (12) of claim 10, 11 or 12, further comprising a third subset of fiber bodies (26A; 26B; 26C; 26D), each being shorter than each of the first subset and second subset of fiber bodies (26A; 26B; 26C; 26D).
  14. The insert (12) of any of claims 10 to 13, further comprising a fabric sheath (28C; 28D) wrapped around the bundle.
  15. The insert (12) of any of claims 10 to 14, further comprising silicon carbide particles.

Description

BACKGROUND The present invention relates to ceramic matrix composites and, more particularly, space filling inserts for use in ceramic matrix composite preforms. Many ceramic matrix composite (CMC) components for gas turbine engines have open spaces between plies due to complex geometries. Some of these spaces are too small to form with textile-based plies, but too large to form using individual fiber tows. In such cases, space filling inserts can be used to build upon and prevent large voids in the body of the CMC. These spaces themselves can be complexly shaped, for example, having non-constant geometries in one or more directions. Accordingly, means for optimizing space filling inserts to fill these spaces are desirable. SUMMARY A method of fabricating a variable geometry space filling insert for a ceramic matrix composite component includes arranging a plurality of fiber bodies into a preform insert, applying a polymer binder to the plurality of fiber bodies, trimming at least a first subset of the plurality of fiber bodies such that each of the first subset of fiber bodies is shorter than at least a second subset of fiber bodies, shaping the insert with a forming tool to form a shaped insert. A variable geometry space filling insert for use in a ceramic matrix composite component includes a plurality of fiber bodies in a bundle, the bundle including a first subset of fiber bodies, and a second subset of fiber bodies, each being longer than each of the first subset of fiber bodies. Features of embodiments are set forth in the dependent claims. The documents US2023/145812A1, WO2023/122009A1 and US2008/124512A1 all describe inserts. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified perspective view of a preform with a triangular space filling insert.FIG. 2 is a simplified perspective view of the insert of FIG. 1, showing its non-constant cross-sectional geometry as a function of location along its length.FIGS 3A, 3B, and 3C are simplified side views of alternative preform insert fiber arrangements.FIG. 3D is a simplified cross-sectional view of a preform insert with sacrificial polymer yarns.FIG. 4 is a flowchart illustrating select steps of a method for fabricating a space filling insert for a preform. While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope of the invention as defined in the claims. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings. DETAILED DESCRIPTION This disclosure presents various space filling inserts, sometimes referred to as "noodles," for incorporation into a CMC preform. These inserts can be advantageously pre-shaped to the dimensions of non-uniform open spaces within a preform. FIG. 1 is a simplified perspective view of preform 10 with space filling insert 12. Preform 10 can be used to form a CMC component for use in a gas turbine engine combustor, compressor, and/or turbine section, to name a few non-limiting examples. Preform 10 is formed from multiple plies 14 laid up in such a manner as to form a structure with a desired shape and thickness. Plies 14 can be formed from braided, woven, and/or chopped ceramic fibers or tows. The ceramic material can be silicon carbide (SiC) or another suitable ceramic material. As shown in FIG. 1, plies 14 can be laid up to form walls 16 with curved regions 18. The bending of plies 14 to form curved region 18 can create a void 20 between a subset of plies 14. Void 20 can be too small to effectively fill with additional plies 14. Thus, insert 12 can be formed to have a shape and size generally complementary to void 20. More specifically, insert 12 can be formed to have a complementary triangular cross-sectional geometry, a thickness or width defined in one or a combination of the x and y-axes, and a length extending along the z-axis. Generally speaking, insert 12 is sized and shaped to fill void 20 along the x, y, and z-axes. Other cross-sectional geometries (e.g., rectangular, rounded, curvilinear, etc.) are contemplated herein as appropriate to the geometry of void 20. In some cases, void 20 can have a non-constant (i.e., variable) cross-sectional geometry as a function of location along its length, for example, tapering in the direction of the z-axis, so a similarly shaped insert 12 is necessary to complement the geometry of void 20. Such voids can be found, for example, in airfoil preforms with variably shaped cavities (e.g., trailing edge cavities) in the spanwise (i.e., z-axis) direction. FIG. 2 is a simplified perspective view of insert 12 shown with a variable c