Energy-Dissipation Balance for a Dynamic Viscoelastic Problem with Memory in Domains with Growing Cracks

The principle of conservation of energy implies that a crack growing in a viscoelastic body must satisfy the dynamic energy-dissipation balance, an equality involving the energy dissipated by viscosity and by crack growth. Unfortunately, some models of evolution of a viscoelastic body, like the frequently used Kelvin-Voigt model, imply that the dynamic energy-dissipation balance prevents crack growth. This unrealistic result forces us to use different models to describe the evolution of a viscoe