Interface friction model in split Hopkinson pressure bar tests for engineering materials

Dynamic behavior of engineering materials at high strain-rates is frequently investigated by split Hopkinson pressure bar (SHPB) technique. The uniaxial stress state within an SHPB specimen is one of the fundamental assumptions which determine the accuracy of an SHPB test. However, the uniaxial stress state is not always satisfied within the SHPB specimen in an actual SHPB test due to the existence of some unavoidable negative factors, e.g., interface friction constrains on the contact surface between the SHPB specimen and the end of pressure bars. A kinetic interface friction model was proposed based on kinetic friction tests to describe the variation of kinetic friction coefficient with the maximum radial relative velocity between the SHPB specimen and steel pressure bars. It shows that the proposed kinetic interface friction model can fit the kinetic friction results well.