Thermodynamics and continuum fracture mechanics for nonlocal-elastic plastic materials

摘要

Nonlocal elasticity is used as an improved elasticity model which engenders no crack-tip stress singularities and thus makes applicable the classical stress-based failure criteria. Considering nonlocal-elastic plastic materials exposed to softening by particle decohesion in a process surface and to subsequent surface separation by fracture, fracture mechanics is addressed within the framework of irreversible internal-variable thermodynamics in the hypothesis of small strains and arbitrary (but sufficiently regular)fracture surface(crack surface plus process surface). The state equations and the energy dissipation densities are derived for the bulk material and for the process surface, for both of which thermodynamically consistent evolutive equations are also proposed.