Temperature effects on the mechanical behavior of aluminum foam under dynamic loading

Series of experiments are conducted to investigate the dynamic behaviors of aluminum foam subjected to impacting loading at different temperatures. A visualized high-temperature furnace, based on the Split Hopkinson Pressure Bar (SHPB) device, is designed to observe the dynamic deformation process of meso-structures during impacting. To modify the thermal gradient effects in bars, a long-projectile directly impacting the SHPB device is introduced to study the dynamic stresses uniformity of specimens under high temperatures. The results show that the strain rate sensitivity of aluminum foam increases as the temperature increases. A simplified formula of the temperature effect on strain rate is proposed to obtain a better relationship with the experimental data. The high-speed photography illustrates that the deformation of aluminum foam under dynamic loading mainly results from the plastic bending of the cell wall at elevated temperatures, but there exist more buckling, tearing and debris profiles at room temperatures.