Multifunctional composite material including a viscoelastic interlayer

A method of manufacturing a structure of composite material comprising:

• a structural component in a form of a matrix;
• a structural component in a form of fiber;
• a layer of viscoelastic material, which comprises a polymer with glass transition temperature that is less than −55° C. and with a melting temperature for a thermoplastic polymer or degradation temperature for a thermostable polymer that is greater than 180° C.;
• and
• a layer of impact-protection material;
• the method comprising:
• A) laminating the matrix and the fiber by an automatic method, such as an automatic tape lay-up method or fiber placement method, to produce a laminated part, the laminated part being subjected to an autoclave curing or setting cycle to produce a first layer comprising laminated material;
• B) adding a second layer comprising viscoelastic material to produce an assembly comprising the second layer on the first layer;
• C) adding a third layer comprising impact-protection material on top of the assembly comprising the second layer on the first layer, the third layer forming an outermost layer of the structure of composite material, and the third layer being electrically conductive;
• wherein:
• a thickness of the second layer is 0.1-0.2 mm,
• the third layer has a maximum thickness substantially equal to one-third of a total thickness of the structure of composite material, and
• the third layer has a minimum thickness greater than 22% of the total thickness of the structure of composite material, such that a flexural rigidity of the first layer and the third layer is equalized, so that the interlaminar shear between the first layer and the third layer is increased.