Contribution of interlaminar stresses to damping in thick laminated composites under uniaxial extension

The principal objectives of this paper are to describe the development of a strain energy method in finite element form for characterizing the effects of interlaminar stresses on damping in thick laminated composites under uniaxial extension, and to give some typical results. To account for the effects of interlaminar stresses on damping, the energy dissipation of a vibrating laminate is calculated on the basis of three-dimensional states of stress. The interlaminar damping is found to the particularly important over a particular range of fiber orientations. Further investigation of the effect of interlaminar damping in thick laminated composites is also performed by increasing the number of laminae. The size of the ‘boundary layer’ region near free edges and at lamina interfaces was found to be related to the interlaminar damping. It appears that there exists an optimal value of the laminate width-to-thickness ratio for maximizing the contribution of interlaminar damping and the total laminate damping.