# US 10,479,478 B2 · Composite material suitable for a morphing skin > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,478 B2 - Document ID: US10479478B2 - Status: Granted - Kind: B2 - Application number: 13/989,453 - Filed: 2013-03-28 - Published: 2015-05-21 - Granted: 2019-11-19 - Earliest claimed: 2012-03-30 - Assignees: Mbda UK Limited; Imperial College of Science, Technology and Medicine - Applicants: MBDA UK Limited; Imperial College of Science, Technology and Medicine - Inventors: Mohammed Azad Hussain; Anthony Machell; Paul Robinson; Henry Alexander Maples; Charnwit Tridech; Alexander Bismarck - Web page: https://patentgrep.com/patent/US10479478B2 ## CPC - B64C 3/48: by relatively-movable parts of wing structures - B29C 61/00: Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor (for surface shaping B29C59/18; for lining articles B29C63/38; for joining preformed parts B29C65/66 {; for packaging B65B53/00; connecting arrangements or other fittings for plastics pipes using shrink-down material F16L47/22, electrical connections insulated using heat shrinking insulating sleeves H01R4/72; cable junctions protected by sleeves H02G15/18}) - B29C 70/086: {and with one or more layers of pure plastics material, e.g. foam layers (applying a non-preformed coating, e.g. a gel-coat, B29C37/0025; with foam blocks B29C70/86)} - B29C 70/205: {the structure being shaped to form a three-dimensional configuration} - B64C 3/20: Integral or sandwich constructions - C08L 33/26: Homopolymers or copolymers of acrylamide or methacrylamide - C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins - B64C 2003/445: {by changing shape according to the speed, e.g. by morphing} - Y02T 50/40: Weight reduction - B64C: AEROPLANES; HELICOPTERS - 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) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A morphing skin for an air vehicle structure, the skin being formed by a composite material which includes: a multiplicity of fibers, a matrix incorporating the fibers, and a thermo-sensitive material, such as a thermo-plastic. The thermo-sensitive material can be reversibly transitionable in response to a change in temperature, between (i) an ambient temperature mode in which the thermo-sensitive material is capable of transferring loads in the composite material, and (ii) a heated mode in which the ability of the thermo-sensitive material to transfer the loads is reduced. This can allow the stiffness of the skin to be temporarily reduced to enable the skin to be morphed into a different shape. ## Claims ### Claim 1 A morphing skin for an air vehicle structure, the skin comprised of a composite material comprising: a multiplicity of fibers coated with a thermo-sensitive material which is reversibly transitionable in response to a change in temperature, between: (i) an ambient temperature mode in which the thermo-sensitive material will transfer loads in the composite material, and (ii) a heated mode in which an ability of the thermo-sensitive material to transfer loads is reduced, and a matrix material that incorporates said fibers coated with a thermo-sensitive material, the matrix material remaining stiff when the thermo-sensitive material is heated; wherein: the thermo-sensitive material reduces skin stiffness in the heated mode, allowing a change in shape of the skin in the heated mode and maintaining a changed shape of the skin in the ambient mode. ### Claim 2 (depends on 1) A morphing skin according to claim 1, wherein the thermo-sensitive material is a thermoplastic. ### Claim 3 (depends on 1) A morphing skin according to claim 1, wherein when in the heated mode, the thermo-sensitive material is at a temperature above a transition temperature, such that the thermo-sensitive material has changed state. ### Claim 4 (depends on 1) A morphing skin according to claim 1, wherein the composite material comprises: a first layer comprising said multiplicity of fibers coated with the thermo-sensitive material and incorporated into said matrix material; and a layer of thermo-sensitive material, adjacent to the first layer. ### Claim 5 (depends on 4) A morphing skin according to claim 4, wherein the composite material comprises: a plurality of layers, each of which comprises said multiplicity of fibers coated with the thermo-sensitive material and incorporated into said matrix material, the plurality of layers interleaved with layers of thermo-sensitive material. ### Claim 6 (depends on 1) A morphing skin according to claim 1 wherein the fibers in said multiplicity of fibers are uni-directional. ### Claim 7 (depends on 1) A morphing skin according to claim 1, wherein the skin comprises, or is configured for connection to, a heating apparatus for heating the thermo-sensitive material from the ambient temperature mode to the heated mode. ### Claim 8 (depends on 7) A morphing skin according to claim 7, wherein the fibers in said multiplicity of fibers are electrically conductive and the heating apparatus is configured to pass a current through the multiplicity of fibers to heat the thermo-sensitive material. ### Claim 9 (depends on 1) A morphing skin according to claim 1, wherein the fibers in said multiplicity of fibers are carbon fibers. ### Claim 10 (depends on 1) A morphing skin according to claim 1, comprising: an actuator for changing and reverting a shape of the skin when the thermo-sensitive material is in the heated mode. ### Claim 11 A method of morphing a skin on an air vehicle, comprising: (i) heating the skin, the skin being configured to reversibly reduce in stiffness in reaction to an increase in temperature; (ii) deforming the skin; and (iii) cooling the skin in the deformed state, the skin being configured to return to higher stiffness in reaction to a decrease in temperature; wherein the skin comprises a composite material comprised of a multiplicity of fibers coated with a thermo-sensitive material, and a matrix material that incorporates said fibers coated in a thermo-sensitive material; wherein the thermo-sensitive material is reversibly transitionable in response to a change in temperature, between: (i) an ambient temperature mode in which the thermo-sensitive material will transfer loads in the composite material, and (ii) a heated mode in which an ability of the thermo-sensitive material to transfer loads is reduced, thereby reducing skin stiffness; the matrix material remaining stiff when the thermo-sensitive material is heated, and the thermo-sensitive material thereby reducing a stiffness of the composite material in the heated mode, allowing a change in shape of the skin in the heated mode, and maintaining a changed shape of the skin in the ambient mode. ### Claim 12 (depends on 11) A method according to claim 11 wherein heating of the skin comprises passing an electrical current through the multiplicity of fibers. ### Claim 13 An article comprising a composite material which comprises: a multiplicity of fibers coated with a thermo-sensitive material, and a matrix material that incorporates said fibers coated in a thermo-sensitive material; wherein the thermo-sensitive material is reversibly transitionable in response to a change in temperature, between: (i) an ambient temperature mode in which the thermo-sensitive material will transfer loads in the composite material; and (ii) a heated mode in which an ability of the material to transfer the loads is reduced, thereby reducing a stiffness of the composite material; the matrix material remaining stiff when the thermo-sensitive material is heated, the thermo-sensitive material thereby reducing a stiffness of the composite material in the heated mode, allowing a change in shape of the article in the heated mode, and maintaining a changed shape of the article in the ambient mode. ### Claim 14 (depends on 1) The morphing skin according to claim 1, wherein said thermo-sensitive material is a thermoplastic polymer and said matrix is an epoxy matrix. ### Claim 15 (depends on 14) The morphing skin according to claim 14, wherein said thermoplastic polymer is selected from poly(methyl methacrylate-co-acrylamide), polystyrene, and liquid crystal polymer.