Numerical Simulation and Experiments for Dynamic Material Properties of Aluminium Alloy in SHPB Experiment using Pulse Shaping Method

Abstract

For the analysis of high speed forming such as electromagnetic forming and electrohydraulic forming, dynamic material properties are required. The split Hopkinson pressure bar (Kolsky bar) was suggested for measuring dynamic material properties from 100 to 10000 /sec strain rate. In the SHPB experiments, the assumption is needed that specimen between incident bar and transmitted bar reaches the dynamic stress equilibrium. For the derivation of average engineering strain and average engineering stress in SHPB experiments, the stress wave at the front and the back of specimen should match each other. A pulse shaping method helps to improve the stress equilibrium of specimen. As one of the various pulse shaping methods, a method of attaching a pulse shaper in front of incident bar was carried out. Numerical simulation and SHPB experiments was performed for verification about pulse shaper effect. The result of experiments and numerical analysis show that the pulse shaper contributes to the dynamic stress equilibrium. The dynamic material properties of Al6061-T6 were obtained, and the simulation was implemented by inputting that properties. As a result of comparing the experiments with new simulation, it was confirmed that the error of specimen length was within 5%.