Damping characteristics of fabric and laminated Kevlar composites

A set of experimental tests on damping coefficient measurements for Kevlar fibre composite samples, both fabric and laminated, is presented. The damping coefficient values, which are independent of the composite Young's modulus value and of the type (fabric or laminate), are greater than typical values for carbon or glass fibre composites. This behaviour can be explained by realizing that in Kevlar composites the fibre behaves as a viscoelastic material and its damping coefficient is of the same order as that of the matrix. The prediction of the damping coefficients by an energy approach validates the experimental results.