Theoretical analysis of the static and dynamic response of tensor skin

Abstract

Comprised of cover ply, tensor ply and carrying ply, tensor skin is a kind of composite sandwich structure developed to improve the helicopter's crashworthiness in water impacts. In this study, a theoretical model is proposed to analyze the static and dynamic response of a kind of tensor skin. The whole response of tensor skin is divided into three stages: an elastic deformation stage of the whole beam; an unfolding stage of the tensor ply; and a stretching stage of the tensor ply. At the beginning of impact, the whole beam undergoes elastic deformation until the breakage of the cover and carrying plies; then the tensor ply left is unfolded and stretched to absorb more impact kinetic energy.In the unfolding stage, by adopting the rigid, perfectly plastic material idealization, a deformation mechanism with stationary plastic hinges is proposed. It is found that the static critical pressure first decreases then increases with the increasing central deflection. The static critical pressure varies with the geometric parameters, but the total energy dissipated in the unfolding stage is independent of the geometric parameters. The residual kinetic energy at the end of unfolding stage will be dissipated by the plastic stretching. The dynamic responses of the tensor skin are analyzed for step loaded pressure and rectangular pressure pulse. It is verified that the theoretical predictions display very good agreement with the corresponding finite element simulations.