Analysis of the impact of a sharp indenter

The present work investigates the impact of a sharp indenter at low impact velocities. A one-dimensional model is developed by assuming that the variation of indentation load as a function of depth under dynamic conditions has the same parabolic form (Kick’s Law) as under static conditions. The motion of the indenter as it indents and rebounds from the target is described. Predictions are made of the peak indentation depth, residual indentation depth, contact time, and rebound velocity as functions of the impact velocity, indenter mass and target properties. Finite element simulations were carried out to assess the validity of the model for elastoplastic materials. For rate-independent materials agreement with the model was good provided the impact velocity did not exceed certain critical values. For ratedependent materials the relationship between load and depth in the impact problem is no longer parabolic and the model predictions cannot be applied to this case. The rate-dependent case can be solved by incorporating the relationship between the motion of the indenter and the dynamic flow properties of the material into the equation of motion for the indenter.