Failure analysis of elasto-plastic material models on different levels of observation

This paper aims at characteristic failure mechanisms of cohesive frictional materials at two levels of observation: (a) at the macroscale of continuum elastoplasticity, and (b) at the microscale of active microplanes with arbitrary orientation. Thereby, the criteria for the loss of uniqueness and the loss of ellipticity will be discussed for a macroscopic as well as a microplane-based anisotropic plasticity formulation. In addition, conditions for shear dilatancy will be developed at the two scales which illustrate the necessity to couple normal and shear components at each microplane.