Abstract
A strain rate effect on load-displacement relation by instrumented a sharp indentation was investigated for pure Aluminum which has high strain rate dependence of strength. When micro-indentation tests were carried out by using a sharp indenter (Berkovich type) at a loading rate of 07-70mN/s the indentation load rose with the loading rate. Finite Element Method was used for the indentation analysis in comparison with experiment. The load increase behavior could be simulated by dynamic FEM with the Cowper-Simonds constitutive equation which includes the strain rate dependence of strength. The FE simulation showed the strain rate under the indenter reaches dynamic range and it caused the load increase. The strain rate under the indenter depends on not only the loading rate but also the indenter angle. If the relationship between the load increase and the indentation test condition is constructed, the strain rate dependence of strength may be evaluated by indentation test.
