A NUMERICAL MODEL FOR SIMULATION OF CRACKING PROCESS IN QUASI-BRITTLE MEDIUM

Abstract

This paper presents a numerical model for simulation of cracking process in quasi-brittle medium. The physically nonlinear analysis begins using the Standard Finite Element Method - FEM, through which the initial medium degradation is simulated in a distributed manner employing constitutive models that consider the medium, even though degraded, remains continuous. The threshold stage of cracks nucleation is indicated by singularity of the acoustic tensor, which provides the classical strain localization condition. The presence of cracks is simulated through kinematic method that incorporates the discontinuities by using enriched interpolations based on the Generalized Finite Element Method - GFEM, whereas the cracks propagation is also indicated by singularity of the acoustic tensor. The cohesive forces acting on the crack plane are simulated incorporating to the enrichment process a discrete constitutive model, which is the relationship between stresses and displacements in the crack path and is based on the concept of cohesive crack. This model has the advantage of not having to pre-set nucleation region and crack path nor having to redefine the mesh during processing. The implementations have been performed on the INSANE - Interactive Structural ANalysis Environment platform. Keywords: cracking process, distributed degradation, cracks nucleation, GFEM, cracks propagation.