Numerical simulation of strength envelope and fracture patterns of concrete under biaxial loading

A numerical model that can simulate the fracture process of plain concrete under variety of plane stress conditions is introduced and used to simulate the fracture patterns of concrete specimens subjected to different combinations of biaxial loadings. In this numerical model, the concrete is assumed to be a three-phase composite composed of matrices, aggregates and interfaces between them. The finite element program is employed as the basic stress analysis tool when the elastic damage mechanics is used to describe the constitutive law of meso-level element and the maximum tensile strain criterion and Mohr-Coulomb criterion are utilised as damage threshold. The numerical simulation predicts well the strength envelope and cracking patterns of concrete specimens under different biaxial loading conditions