# US 11,440,277 B2 · Method of repairing composite sandwich panels > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,277 B2 - Document ID: US11440277B2 - Status: Granted - Kind: B2 - Application number: 16/846,373 - Filed: 2020-04-12 - Published: 2021-10-14 - Granted: 2022-09-13 - Earliest claimed: 2020-04-12 - Assignees: Textron Innovations Inc. - Applicants: Bell Textron Inc. - Inventors: Suvankar Mishra - Web page: https://patentgrep.com/patent/US11440277B2 ## CPC - B29C 73/10: using patches sealing on the surface of the article (B29C73/14 takes precedence) - B29C 73/24: Apparatus or accessories not otherwise provided for - B64C 27/473: Constructional features - B64F 5/40: Maintaining or repairing aircraft - B29C 73/26: for mechanical pretreatment - B29K 2105/06: containing reinforcements, fillers or inserts - B29L 2031/3076: {Aircrafts (blades, propellers B29L2031/08)} - B64C 2027/4736: {from composite materials} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B64C: AEROPLANES; HELICOPTERS - B64F: GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract A method of repairing an aircraft component having a structural core surrounded by an exterior skin of composite material includes removing damaged material from the component to create a cavity therein that exposes an undamaged portion of the structural core, applying a septum comprising composite material to the undamaged portion of the structural core within the cavity such that an orientation of fibers in the septum matches an orientation of fibers in the exterior skin, placing a repair core onto the septum in the cavity such that cells of the repair core are in alignment with cells of the undamaged portion of the structural core, inserting a shim into the cavity along a perimeter of the repair core, applying a patch that covers the cavity to the exterior skin, and co-curing the septum, shim, and patch to bond the repair core in place within the cavity. ## Claims ### Claim 1 A method of repairing an aircraft component having a structural core surrounded by an exterior skin of composite material, the method comprising: removing damaged material from the component, creating a cavity therein that exposes an undamaged portion of the structural core; applying a septum comprising composite material to the undamaged portion of the structural core within the cavity such that an orientation of fibers in the septum matches an orientation of fibers in the exterior skin; placing a repair core onto the septum in the cavity such that cells of the repair core are in alignment with cells of the undamaged portion of the structural core; inserting a shim into the cavity along a perimeter of the repair core, wherein the shim comprises a fiber-reinforced polymer (FRP) material rolled into an elongate shape comprising a substantially solid cross-section comprising the FRP material with none of the repair core disposed within the cross-section; applying a patch that covers the cavity to the exterior skin; and co-curing the septum, shim, and patch to bond the repair core in place within the cavity; wherein the shim is maintained in a rolled state after applying the patch and during the co-curing. ### Claim 2 (depends on 1) The method of claim 1, wherein removing the damaged material comprises forming a planar surface along a bottom of the cavity. ### Claim 3 (depends on 1) The method of claim 1, wherein the septum comprises a ply of fiber-reinforced polymer (FRP) material. ### Claim 4 (depends on 3) The method of claim 3, wherein the exterior skin comprises a plurality of layers of FRP material and wherein the septum is applied such that the orientation of fibers in the septum matches that of fibers in an innermost layer of the plurality of layers. ### Claim 5 (depends on 4) The method of claim 4, wherein the septum and the exterior skin are made of the same FRP material. ### Claim 6 (depends on 5) The method of claim 5, wherein the shim is made of the same FRP material as the septum and the exterior skin. ### Claim 7 (depends on 1) The method of claim 1, wherein the shim comprises a cylinder of composite material. ### Claim 8 (depends on 1) The method of claim 1, wherein inserting the shim comprises positioning the shim between a perimeter surface of the repair core and an inner surface of the cavity. ### Claim 9 (depends on 1) The method of claim 1, wherein the cells of the structural core are made of Polyetherimide (PEI) thermoplastic material. ### Claim 10 (depends on 9) The method of claim 9, wherein the cells of the repair core are made of the same PEI thermoplastic as the structural core. ### Claim 11 (depends on 10) The method of claim 10, wherein the cells of the structural core are arranged in a first pattern and the cells of the repair core are arranged in a second pattern that matches the first pattern. ### Claim 12 (depends on 11) The method of claim 11, wherein alignment of cells of the repair core with cells of the structural core comprises coaxial alignment of the cells. ### Claim 13 (depends on 1) The method of claim 1, wherein the repair core comprises a plurality of sections, each section having a geometry that conforms to a corresponding portion of a bottom surface of the cavity. ### Claim 14 (depends on 13) The method of claim 13, further comprising: inserting a second shim between respective perimeter surfaces of first and second repair core sections of the plurality that are adjacent to one another in the cavity.