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 the lowvelocity impact response of rigidly supported, two-sided clamped, simply supported and four-sided clamped composite sandwich panels. The composite sandwich panels have orthotropic facesheets and are symmetric. Analytical solutions for the transient deformation response of the sandwich panels are presented in this paper, and analytical predictions of impact damage initiation are given in a companion paper. Equivalent masses are derived by assuming velocity distributions and calculating average kinetic energies (KEs) in terms of the amplitude of the top facesheet indentation and the global panel deflection. Equivalent spring and dashpot resistances are derived from 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.