Plastic dynamic breakup of a free-free beam subjected to impact at two free ends

The dynamic plastic failure characteristics of a free-free beam subjected to impact at its two free ends by moving concentrated masses are studied. Based on rigid, perfectly plastic (r-p-p) material idealization the complete solutions in closed form are obtained. Attention is focused on the permanent distribution of the curvature and the cross-sectional rotation along the axis of the beam, so as to predict the possible breakup cross-section in the beam. The results based on present r-p-p model are compared with those predicted by FEM analysis based on elastic, perfectly plastic (e-p-p) material idealization. It is shown that the agreement is good between the predictions of the r-p-p and e-p-p models on the cross-section positions with maximum rotation. The breakup of the impinged beam may occur on these positions most possibly.