Stress wave induced by the longitudinal collision of an elasto-plastic bar with either a rigid wall or an elastic bar was analysed numerically. The constitutive equation of the elasto-plastic bar was assumed to be rate-independent.
A steep rise in axial stress at the impact end occurred immediately after collision and the peak value of the average axial stress within the cross section of the impact end was found to be equal to the predicted value as calculated using the stress-strain relationship in a uni-axial strain state. This is because, during a short period after impact, the immediate area of the impact end is in a state of uni-axial strain caused by its radial inertia.
This high stress level dropped and relaxed as the dilatational wave propagated from the cylindrical surface to the central axis. This stress rise was apparent only in the space equivalent to one measurement of the bar's diameter. Beyond that point there was no particular rise in stress.
The stress level oscillated and asymptotically approached to a constant value, which is calculated by Karman's theory in a uni-axial stress state.
