Dynamic models for low-velocity impact damage of composite sandwich panels- Part A: Deformation

Equivalent single and multi degree-of-freedom systems are used to predict t he low-velocity impact response of rigidly supported, two-sided clamped, si mply supported and four-sided clamped composite sandwich panels. The compos ite sandwich panels have orthotropic facesheets and are symmetric. Analytic al solutions for the transient deformation response of the sandwich panels are presented in this paper, and analytical predictions of impact damage in itiation are given in a companion paper. Equivalent masses are derived by a ssuming velocity distributions and calculating average kinetic energies (KE s) in terms of the amplitude of the top facesheet indentation and the globa l panel deflection. Equivalent spring and dashpot resistances are derived f rom the static load-indentation response and adjusted with dynamic material properties of the facesheet and core. Analytical predictions of the impact force compare well with experimental values from three independent studies . (C) 2001 Elsevier Science Ltd. All rights reserved.