Dynamic fracture mechanics

Abstract

So far, our investigations of crack initiation and propagation have always been based on the assumption of quasistatic conditions. This is no longer justified when inertia forces or high strain rates significantly affect the fracture behavior. It is, for instance, well known that a material is more likely to fail under impulsive dynamic loading than in case of a slowly applied load. One reason for this is the different material behavior: plastic or viscous flow is increasingly suppressed at higher loading rates and a material often behaves more brittle in the dynamic case than in the static case. This and possibly different failure mechanisms in the process zone may lead to a change of the fracture toughness. Another reason is due to the fact that the inertia forces in case of dynamic loading can cause higher stresses in the vicinity of a crack tip than in the corresponding quasistatic case.