Dynamic Problem of Expanding Crack under Concentrated Load

An analysis is presented on a dynamic problem of two-dimensional crack which is subjected to a time-increasing concentrated load on the surface and expands at both ends at a constant velocity. The dynamic stress intensity factor and the dynamic energy release rate are calculated for a linear elastic solid. A further extension of elastic analysis with simulated plasticity is made by the strip yield model, the Dugdale's model. It is shown that the plastic zone length, the COD and the energy release rate are expressed by functions decreasing with the crack velocity.