Mechanical response and dynamic deformation mechanisms of closed-cell aluminium alloy foams under dynamic loading

The dynamic compressive response of closed-cell (CYMAT™) stabilised aluminium alloy foams (SAF) has been investigated using a modified Split Hopkinson Pressure Bar (SHPB) in conjunction with a high-speed camera. Tests have been carried out on 45 mm diameter and 23 mm thick cylindrical specimens. The elastic-plastic pore collapse mechanism has been investigated using Digital Image Correlation (DIC) and micro-computed X-ray tomography. A stress-strain relationship for individual specimens at different impact velocities has been obtained with the combination of an analytical method and SHPB theory. The large deformation (∼80%) has been measured from eight strain gauges' data using a wave separation algorithm. The test results exhibited a significant increase in elastic and plastic strength during the pulse loading. The X-ray tomography data of pre-impacted and post-impacted SAF specimens have been extensively analysed to elucidate the internal elastic-plastic pore collapse mechanisms.