Dynamically induced fracture

Expressions are presented for the stresses generated in the vicinity of a crack tip when a plane transient tension-stress wave, which is incident under an arbitrary angle, is diffracted by the crack. The effect of ductility effects on the combined Mode I and Mode II fractures is examined by assuming that yielding is restricted to a thin strip in the plane of the crack. Within this zone of yielding the normal stress in a certain defined direction is set equal to a yield stress of the material. It is shown that for a step-stress wave the leading edge of the zone of yielding initially moves at a constant speed, which is computed. The time for rupture at the trailing edge of the zone of yielding is also determined.