ABSTRACT

Early fracture mechanics researchers considered dynamic effects, but only for the special case of linear elastic material behavior. In the most general case, dynamic fracture mechanics contains three complicating features that are not present in linear elastic fracture mechanics (LEFM) and elastic–plastic fracture mechanics: inertia forces, rate-dependent material behavior, and reflected stress waves. The dynamic version of LEFM is termed elastodynamic fracture mechanics, where the nonlinear material behavior is neglected, but inertia forces and reflected stress waves are incorporated when necessary. Dynamic fracture analyses that incorporate nonlinear, time-dependent material behavior are a relatively recent innovation. Dynamic propagation toughness can be measured as a function of crack speed by means of high-speed photography and optical methods, such as photoelasticity and the method of caustics. Time-dependent fracture mechanics approaches are required when creep failure is controlled by a dominant crack in the structure.