Dynamic instabilities and failures in impact tension, compression and shear

Abstract
Several aspects of Dynamic Fracture Mechanics and Dynamic Failure Mechanics are discussed in this paper. In the first part the local fracture criteria are briefly discussed, but the main part is focused on the failure criteria to be applied in fast or impact loading. A phenomenon of delayed fracture is discussed when a stationary crack is loaded by an impulse in tension or shear. Some local failure criteria are evoked and applied to cases of dynamic failures in tension, compression and shear. Conditions for stability in different modes of dynamic loading leading to failures are defined. The Critical Impact Velocities (CIV) in tension and shear, as the last stage of dynamic failure, are discussed as well. Another case of dynamic failure is the phenomenon of spalling. A local failure criterion based on delayed accumulation of defects and generalized to a wide range of temperatures is introduced.