Numerical simulation on shear fracture process of concrete using mesoscopic mechanical model

The numerical simulation of the damage and fracture processes of concrete structures has evolved considerably in the past years. In this contribution, a newly proposed mechanical model is used to simulate the fracture behavior of double-edge notched (DEN) and double central notched (DCN) concrete specimens loaded in shear. In this numerical model, the concrete is assumed to be a three-phase composite composed of matrices, aggregates and rnatrix-aggregate interfaces. An elastic finite element program is employed as the basic stress analysis tool while the elastic damage mechanics is used to describe the constitutive law of meso-level element. The maximum tensile strain criterion and Mohr-Coulomb criterion are utilized as damage thresholds. The heterogeneous stress field is obtained from numerical simulation, thus it is found that heterogeneity of mechanical properties has significant effect on the stress distribution in concrete. The crack propagation processes simulated with this model shows good agreement with those of experimental observations. It has been found that the shear fracture of concrete observed at the macroscopic level is predominantly caused by tensile damage at the mesoscopic level. (C) 2002 Elsevier Science Ltd. All rights reserved.