Axial stress waves in an elastic-perfectly-plastic bar

A bar, made from an elastic-perfectly plastic material, fixed at one end, s uddenly has an axial load applied at the other end. After its sudden applic ation, the load is held constant. If the load is less than half the yield l oad for the bar, and in the absence of damping, the load causes a stress wa ve to pass up and down the bar, all behaviour being elastic. At any point w ithin the bar length, the stress varies, in a stepwise fashion, between zer o, and twice the stress corresponding to the applied load. This is the clas sical elastic solution. However, if the load is greater than half the yield load, when the stress wave first hits the fixed end, yielding will occur, and a simple model is proposed in this paper to allow for yielding. The mod el incorporates two zones separated by the stress wave, as in the elastic s olution, together with a third zone, concentrated, and adjacent to the fixe d support, in which all plastic straining takes place. The paper describes and verifies the model, and presents the predictions that it gives for vari ous levels of load. (C) 2001 Elsevier Science Ltd. All rights reserved.