Low velocity transverse impact response of a composite sandwich plate subjected to a rigid blunted cylindrical impactor

The low velocity impact problem of a composite sandwich plate impacted by a rigid blunted cylinder is analytically studied. The sandwich plate is composed of laminated face sheets and a rigid-plastic core which can be rigidly supported or simply supported. In contrast to the previous works, the face sheets are with no limitation for the stacking sequence. Also, the effects of in-plane displacement components u and v as well as initial in-plane forces acting on the edges of the sandwich plate are incorporated in the present article. First, by using the minimization of the total potential energy approach, closed form solutions are derived for the static indentation problem and the contact law (contact force-indentation relation) is determined. Then, spring-mass-dashpot models are developed to study the low velocity impact problem. The characteristics of the equivalent spring and dashpot are identified from the derived contact law and by incorporating the effect of the dynamic material properties of the sandwich plate. Analytical predictions for the impact force history are compared well with the experimental and analytical results in the literature. Results of a parametric study show that the stacking sequence of the face sheet has an insignificant effect on both the impact force and the contact duration. Furthermore, if the zero in-plane forces case to be considered as a reference state, the positive in-plane forces increase the impact force and decrease the contact duration, while the negative in-plane forces, with exactly the opposite effects, decrease the impact force and increase the contact duration.