BRITTLE FRACTURE UNDER DYNAMIC LOADING CONDITIONS.

The extension of a flaw at the diffraction of elastic stress waves is examined by employing the balance of rates of energies as a fracture criterion. It is shown that the balance of rates of energies can be expressed in terms of expressions for the field variables in the plane of fracture and in the immediate vicinity of the tip of the crack. Due to a dynamic overshoot effect, which depends on the rate of change of the stress at the wavefront and therefore on the rate of application of the loads, the magnitudes of critical loads decrease when the loads are applied more rapidly.