Anisotropic and Unilateral Damage Application to Concrete

Abstract

A theoretical model is presented suitable for the description of the damaging process in brittle materials. The model is based on damage mechanics: it features two second order symmetric damage tensors, representative of surface damage induced by tensile and compressive strains activates at different orientations to the principal strain directions, according to the sign of the principal strain which attains a damage threshold, and a scalar variable representative of volumetric damage. In this model, two separate damage variables, one for tension and the other for compression, allow to model the non-symmetric behaviour and the unilateral effect. Damage activation is governed by two different loading functions evolving with nonreciprocal hardening and softening. The capabilities of the model in describing the mechanical response of material elements subjected to non-proportional stresses are illustrated.