High rate compressive behavior of aluminum foams by modified SHPB technique

The two-wave-separation method is employed for the large strain measurements in compressive tests on Alporas aluminum closed cell foams. Specimens 50mm in diameter and 25mm 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 stressstrain 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 also has a great influence on the densification strain, normalized plateau stress and energy absorption capacity of foams, indicating that Alporas closed cell aluminum foams are sensitive to strain rate.