Composite material suitable for a morphing skin

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.

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.