Approximation and characterization of quasi-static H1-evolutions for a cohesive interface with different loading-unloading regimes

We consider the quasi-static evolution of a prescribed cohesive interface: dissipative under loading and elastic under unloading. We provide existence in terms of parametrized BV-evolutions, employing a discrete scheme based on local minimization, with respect to the H-1-norm, of a regularized energy. Technically, the evolution is fully characterized by: equilibrium, energy balance and Karush-Kuhn-Tucker conditions for the internal variable. Catastrophic regimes (discontinuities in time) are described by gradient flows of visco-elastic type.