Heterogeneous structures studied by interphase elasto-damaging model.

For all structures that are constituted by heterogeneous materials, the meso-modelling approach is the most rigorous since it analyzes such structures as an assembly of distinct elements connected by joints, the latter commonly simulated by apposite interface models. In particular, the zero-thickness interface (ZTI) models are extensively used in those cases where the joint thickness is small if compared to the other dimensions of the heterogeneosu material. In ZTI models the constitutive laws relate the contact tractions to the displacement discontinuities at the interface, but in many cases the joint response depends also on internal stresses and strains within the bulkmaterial. In this sense the interphase model represents an enhancement of the ZTI because is able to introduce the effect of internal stresses into the analysis. Particular attention is spent to the definition of a damage model in order to describe the propagation of a fracture inside the interphase element. The damage model is developed in a thermodinamically context for plane stress applications.