Damage Wave Propagation in Elastic-brittle Materials

A theory of damage wave propagation in elastic-brittle materials is developed within the framework of thermodynamics. Because the local extent of damage is a result of microscopic movement of its neighborhood, we include the gradient of damage and the additional kinetic energy in the construction of thermodynamic functions. A specific elastic-brittle material model is presented. The governing equations of the coupled thermo-damage-mechanism are derived. It is shown that the equation of the damage evaluation is a non-linear wave equation and has a solitonic solution of the kink type. The propagation speed is determined using energy analysis. Dissipative mechanisms, like internal friction, irreversible phase transformation and chemical reactions, reduce the speed of damage wave. More detailed discussions are presented in the paper.