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EP-4523896-B1 - COMPOSITE REPAIR

EP4523896B1EP 4523896 B1EP4523896 B1EP 4523896B1EP-4523896-B1

Inventors

  • RICKLESS, KEENAN S.
  • MAJORS, WILLIAM BRANDT

Dates

Publication Date
20260513
Application Date
20240822

Claims (15)

  1. A method (800) of performing a composite repair (204, 502) comprising: forcing (245, 802) a fiber mixture (258) through a composite structure (202, 300, 700) and into a void (210, 304, 704) of the composite structure (202, 300, 700), the fiber mixture (258) comprising an adhesive (260) and a plurality of electromagnetically steerable fibers (264, 220, 602); applying (804) an electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) of the composite structure (202, 300, 700); and curing (286, 806) the adhesive (260) of the fiber mixture (258) to form the composite repair (204, 502) with structural capabilities (206).
  2. The method (800) of claim 1 further comprising: forming (250, 808) a number of injection holes (214, 402) in the composite structure (202, 300, 700) to reach the void (210, 304, 704) in the composite structure (202, 300, 700), wherein forcing (245) the fiber mixture (258) into the void (210, 304, 704) comprises forcing (245) the fiber mixture (258) through at least one hole of the number of injection holes (214, 402) and into the void (210, 304, 704).
  3. The method (800) of claim 1 or 2, wherein (814) applying the electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) comprises alternatingly applying the electromagnetic field (280) as the fiber mixture (258) is forced into the void (210, 304, 704).
  4. The method (800) of any preceding claim, wherein (816) applying the electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) comprises applying pressure to fibers lodged within the void (210, 304, 704) as the fiber mixture (258) is forced into the void (210, 304, 704).
  5. The method (800) of any preceding claim, wherein (818) applying the electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) comprises increasing filling of the void (210, 304, 704) with the fiber mixture (258).
  6. The method (800) of any preceding claim, wherein (820) applying the electromagnetic field (280) to the fiber mixture (258) comprises alternatingly activating the electromagnetic field (280) as the fiber mixture (258) is forced into the void (210, 304, 704), the method further comprising: alternatingly (822) applying a second electromagnetic field (284) within the void (210, 304, 704) as the fiber mixture (258) is forced into the void (210, 304, 704) and when the electromagnetic field (280) is not active, the second electromagnetic field (284) having a different direction than the electromagnetic field (280).
  7. The method (800) of any preceding claim, wherein (810) forcing (245) the fiber mixture (258) into the void (210, 304, 704) comprises vacuum infusing the fiber mixture (258) into the void (210, 304, 704) and/or injecting the fiber mixture (258) into the void (210, 304, 704).
  8. The method (800) of any preceding claim, wherein (824) applying the electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) comprises aligning at least a portion of the plurality of electromagnetically steerable fibers (264, 220, 602) in a Z-direction (226) in the void (210, 304, 704).
  9. The method (800) of any preceding claim, wherein (826) applying the electromagnetic field (280) to the fiber mixture (258) within the void (210, 304, 704) comprises orienting a first set of fibers (222, 606) of the plurality of electromagnetically steerable fibers (264, 220, 602) in a first direction (224), the method further comprising: orienting (828) a second set of fibers (228, 608) of the plurality of electromagnetically steerable fibers (264, 220, 602) in a second direction (230).
  10. The method (800) of any preceding claim, wherein (830) curing (286) the adhesive (260) of the fiber mixture (258) is performed while a first set of fibers (222, 606) of the plurality of electromagnetically steerable fibers (264, 220, 602) is in a first direction (224) and while a second set of fibers (228, 608) of the plurality of electromagnetically steerable fibers (264, 220, 602) is in a second direction (230).
  11. The method (800) of claim 10, wherein (832) the first set of fibers (222, 606) and the second set of fibers (228, 608) are different from each other based on at least one of a fiber length (232), a fiber type (234), or a fiber coating (236).
  12. A composite structure (202, 300, 700) with a composite repair (204, 502) having structural capabilities (206), the composite structure (202, 300, 700) comprising: a plurality of cured composite plies (208, 302, 702) with a void (210, 304, 704) creating a separation (212) within the plurality of cured composite plies (208, 302, 702); a number of injection holes (214, 402) connecting the void (210, 304, 704) to an exterior (216) of the plurality of cured composite plies (208, 302, 702); and a cured resin (218) with a plurality of electromagnetically steerable fibers (264, 220, 602) within the separation (212) forming the composite repair (204, 502) and configured to transmit forces to composite plies in contact with the composite repair.
  13. The composite structure (202, 300, 700) of claim 12, wherein the plurality of electromagnetically steerable fibers (264, 220, 602) comprise a first set of fibers (222, 606) oriented in a Z-direction (226) relative to the plurality of cured composite plies (208, 302, 702).
  14. The composite structure (202, 300, 700) of claim 12 or 13, wherein: the plurality of electromagnetically steerable fibers (264, 220, 602) comprise a first set of fibers (222, 606) oriented in a first direction (224) and a second set of fibers (228, 608) oriented in a second direction (230); and, optionally, the first set of fibers (222, 606) and the second set of fibers (228, 608) are different from each other based on at least one of a fiber length (232), a fiber type (234), or a fiber coating (236).
  15. An aircraft (100) comprising the composite structure (202, 300, 700) of any of claims 12 to 14.

Description

BACKGROUND INFORMATION Field: The present disclosure relates generally to composite manufacturing and more specifically to repair of composite structures. Background: Repairs of composites often have a "knock-down factor" applied. A "knock-down factor" is a calculated reduction in strength or other mechanical characteristic due to the repair. A "knock-down factor" limits the applicability of the composite part. Different types of repairs have different "knock-down factors". Cost and complexity of composite repair is correlated to the "knock-down factor." The more complicated, more complex, and often more expensive the composite repair procedure, the lower the "knockdown factor." Composite repair with reduced "knock-down factor" results in significant increases in repair complexity, repair analysis, and cost. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues. For example, it would be desirable to present new composite repair methods with a reduced complexity and reduced "knock-down factor". US 6385836, in accordance with its abstract, states a method for repairing a composite material having an internal void includes identifying the location of the internal void and forming a single channel extending from a surface of the composite material to the internal void. The method further includes pulling a vacuum in the internal void and inserting a repair material through the channel into the internal void. EP 3433089, in accordance with its abstract, states apparatus and methods for repairing defects such as porosity and/or edge delamination in composite laminates by infusion of flowable matrix material. In some examples, methods disclosed therein comprise infusing the flowable matrix material into a space in the composite laminate through the use of a formed hole extending at least partially through the composite laminate. In some examples, methods disclosed therein comprise infusing the flowable matrix material into a space in the composite laminate in a stepwise manner. US 2017/173895, in accordance with its abstract, states a method of forming a fibre composite component, the method comprising: providing a plurality of first fibres, the first fibres being arranged in a plurality of layers with an uncured thermoset resin matrix being provided therebetween. The resin matrix comprises a plurality of second electrically conductive fibres suspended therein having a shorter length than the first fibres. The method comprises then applying an energy field to the resin matrix to thereby align the second fibres such that they provide an electrically conductive path between adjacent layers of first fibres to form an electrically conductive fibre network comprising the first and second fibres. The method comprises then inducing an electric current through the electrically conductive fibre network to thereby heat and cure the resin matrix. US 9156240, in accordance with its abstract, states an area of a composite laminate structure is reworked by scarfing the area, generating a 3-D map of the scarfed area, and installing a rework patch that is built based on the 3-D map. SUMMARY In summary there is provided a method of performing a composite repair comprising: forcing a fiber mixture through a composite structure and into a void of the composite structure, the fiber mixture comprising an adhesive and a plurality of electromagnetically steerable fibers; applying an electromagnetic field to the fiber mixture within the void of the composite structure; and curing the adhesive of the fiber mixture to form the composite repair with structural capabilities. The fiber mixture may be forced through at least one injection hole in the composite structure and into the void in the composite structure. There is also provided a composite structure with a composite repair having structural capabilities the composite structure comprising: a plurality of cured composite plies with a void creating a separation within the plurality of cured composite plies; a number of injection holes connecting the void to an exterior of the plurality of cured composite plies; and a cured resin with a plurality of electromagnetically steerable fibers within the separation forming the composite repair and configured to transmit forces to composite plies in contact with the composite repair. Applying the electromagnetic field may comprise applying the electromagnetic field during curing. Applying the electromagnetic field may comprise orienting a first set of fibers of the plurality of electromagnetically steerable fibers in a first direction, the method may further comprise: applying a second electromagnetic field to the fiber mixture to orient a second set of fibers of the plurality of electromagnetically steerable fibers in a second direction. Applying the electromagnetic field may orient only a portion of the plurality of electromagneticall