High rate compressive behavior of aluminum foams by modified SHPB technique

Abstract

The two-wave-separation method is employed for the large strain measurements in compressive tests on Alporas aluminium closed cell foams. Specimens 50 mm in diameter and 25 mm thick, prepared by wire cutting, were tested. Parameters such as the start time for calculating wave pulses and specimen thickness that would greatly influence the experimental results are discussed. Finite element modeling verified that the stress-strain curves obtained using the modified split Hopkinson pressure bar (SHPB) technique are reasonable. The results were compared with those from quasi-static and intermediate strain rate compressive testing. It is shown that the relative density is a major factor that affects the foam properties. Strain rate has a great influence on the densification strain, normalized plateau stress and energy absorption capacity of foams, indicating that Alporas closed cell aluminium foams are sensitive to strain rate.