Experimental Investigation on the Yield Behavior of Aluminum Foams under Combined Stress States

The initial yield behavior of Alporas closed-cell aluminium foams with relative density 8.5% under biaxial loading has been experimentally investigated using the Arcan apparatus and the universal testing machine (INSTRON 5544). The experimental yield surfaces measured from biaxial experiments are compared with various proposed phenomenological yield surface models. The comparison result indicates that the experimental data are consistent with both Miller and Deshpande and Fleck criteria. Biaxial experiments have been carried out on aluminium foams at various loading velocities to study the effect of strain rate on the initial yield surface. The results showed that the initial yield stresses of Alporas closed-cell aluminium foams are not sensitive to the equivalent strain rate ranged from 7.010-3~1.010-1 s-1.