Micromechanical based derivation of traction-separation laws for cohesive model simulations

A general method is proposed for the derivation of traction-separation laws for cohesive models, which is based on numerical simulations of a representative volume element with heterogeneous microstructure. The failure of this microstructure may involve various damage mechanisms, which are to be included in the simulation. From the mesoscopic response of the micromechanical model the complete traction-separation law is extracted, which in general depends on the applied triaxiality and other field quantities like loading rate. The derived traction-separation law can then be used in structural finite element analyses, where the microstructure is not modelled explicitly anymore. Instead of that, phenomenological material laws are included, namely the failure in such simulations is modelled by cohesive interface elements obeying the micromechanically derived traction-separation law identified before.