NORMAL SHEAR CRACKING MODEL - APPLICATION TO DISCRETE CRACK ANALYSIS/

A Simple but general model for normal/shear cracking in quasi-brittle materials is presented. It is defined in terms of the normal and shear stresses on the average plane of the crack and the corresponding norm al and shear relative displacements. A crack surface in stress space d etermines crack initiation under pure tension, shear-tension, or shear -compression loading. Two independent fracture energy parameters are u sed: the classical Mode I fracture energy G(f)(I), and the asymptotic Mode II fracture energy G(f)(IIa) under very high shear-compression an d no dilatancy. The cracking model proposed can be implemented in two ways: directly as the constitutive law of an interface element in the context of discrete crack analysis, or as the law of a generic crackin g plane in a multicrack formulation in the context of smeared crack an alysis. In this paper, the first approach is presented and examples ar e given of numerical constitutive testing and verification with experi mental data.