A new model for cohesive interfaces is presented, based on energy and dissipation
functionals and directly derived from thermodynamic principles, so that it is
compatible with a continuum damage mechanics constitutive model for the
continuum. Degradation of the interface is introduced through the dependency of the
activation function on a driving force, dual to the internal variable of damage. The
activation function of the interface is thus defined in the extended space of the
tractions and of the conjugated forces, making it possible to model opening and
reclosing, eventually with permanent residual relative displacements. An original
feature of the model is that the friction angle degrades with the damage,
modeling the reduction of the surface asperities, so that dilatancy tends to
disappear. The evolution of the interface relative displacements is obtained from
the conjugated dissipation functional, that is ruled by an associated flow
rule.
Keywords
cohesive interface model, crack model, friction
coefficient, damage, fracture energy