Viscoplastic Response of Clamped Beams under Impact Loading

A three-stage analytical model for predicting the final midpoint deflections of viscoplastic, clamped beams under impact loading conditions is presented. The model includes traveling plastic hinges and accounts for strain rate sensitivity by continuously varying the dynamic yield stress parameter during the impact event. This new model is compared both with another impact model and with two different sets of experimental results for steel and aluminum beams. In addition, the finite element program, ABAQUS, is employed to provide a detailed history of the dynamic response of the system. The finite element results are used to assess the appropriateness of the simplifying assumptions contained in the three-stage model. The model predictions are shown to be in good agreement with both sets of experimental results and the assumptions made in developing the model are in general agreement with the ABAQUS predictions.