Patent ID: 7329457

Claim:
A laminate comprising: a sandwich structure comprising: two layers of a composite material containing fibers; a core consisting essentially of a fiber-reinforced composite material, said core being positioned between the two layers; at least a portion of the fibers of the core having a mechanical strength lower than a mechanical strength of at least a portion of the fibers of at least one of the two layers; the fibers of the core comprising a member selected from the group consisting of synthetic fibers, natural fibers, cellulose fibers, or a mixture of any of combination of synthetic, natural, and cellulose fibers, the synthetic fibers comprising a member selected from the group consisting of polyamide fibers, polyolefine fibers, polyester fibers, and polyesterimide fibers, and the natural fibers comprising a member selected from the group consisting of silk fibers, cotton fibers, linen fibers, jute fibers, and hemp fibers; the laminate having a total thickness e less than or equal to 3 mm; the core having a thickness e 2 and the two layers have a total thickness e 3 +e 4 , a ratio between the thickness of the core and the total thickness of the two layers being defined as follows: e 2 / e 3 + e 4 2 ≤ 5.