Evaluation of the effect of the strain rate on the compressive response of a closed-cell aluminium foam using the split Hopkinson pressure bar test

The research here presented is focused on the evaluation of the dynamic behaviour of a closed-cell aluminium foam using the split Hopkinson pressure bar (SHPB) test. On a first approach, the influence of the material of the bars was studied and, as a consequence, polymethylmethacrylate (PMMA) was chosen as the most suitable material to be used in the bars and striker to test the specific aluminium foam considered. This set of bars was manufactured and several dynamic compression tests were carried out. The corresponding stress–strain relation was obtained and the dependence of mechanical parameters of the aluminium foam Alporas 10% on the strain rate was thoroughly analysed. It was possible to conclude that the material exhibits significant strain rate sensitivity, within the tested range of strain rates. The range of strain rate values where the compressive behaviour of the foam is different was also determined.

► PMMA has shown to be suitable material for the dynamic testing of the Alporas foam. ► A dynamic Young’s modulus of the PMMA was estimated by an ultrasonic technique. ► Viscoelastic dispersion and attenuation effects due to the PMMA were corrected. ► We obtained the stress–strain curves of the Alporas foam at different strain rates. ► The mechanical properties of the Alporas foam exhibit some strain rate sensitivity.