A model for erosion at normal impact

Numerical simulations of lip formation indicate that the thermal softening induced flow localisation at the edge of impact craters proposed by Sundararajan is not a general removal mechanism, which was unresolved in Hutchings' model. By considering a mechanism for erosion caused by the residual tensile stress, and applying the Johnson-Cook fracture model, the ratio of the removed volume to the indentation volume and the erosion ductility can be estimated. These are two key problems left unsolved, theoretically, in Hutching's model. The erosion model proposed in this paper can evaluate the influences of strain rate and temperature rise on the erosion rate. Comparisons of the theoretical predictions based on this model and the observed experimental erosion rates are reasonably good.