Experimental and theoretical study of free-free beam subjected to impact at any cross-section along its span

A high-speed camera system is adopted to measure the instantaneous deformation of a free-free beam struck by a projectile at any cross-section along its span. The material in the experiment is made of hard aluminum (LY12R) which is less sensitive to the strain rate. A theoretical model is based on an elastic-plastic linear hardening material and the formulation is derived from the minimum principle in dynamics of elastic-plastic continua at finite deformation in association with a numerical technique. Some experimental results and theoretical predictions are given for the beam impacted at mid-span and 1/4 span, and attention is focused on the dynamic behavior of the beam in the early, transient stage of the response.