ANALYSIS ON FAILURE OF CONCRETE STRUCTURE WITH MULTIPLE CRACKS BASED ON AUGMENTED VIRTUAL INTERNAL BOND METHOD

The Augmented virtual internal bond (AVIB) model is a multi-scale constitutive model based on the virtual internal bond (VIB) theory. It simultaneously accounts for the normal and shear deformation effects of micro bond through Xu-Needleman potential. The stress states of micro elements have significant influence on the compressive strength of brittle materials. In order to reflect the stress effect of micro element, a stress effect coefficient is firstly defined according to the strength criteria and then is introduced into AVIB constitutive model. To model the preexisting cracks, the element partition method (EPM) is used, avoiding the re-meshing and setting-up of contact element. The improved AVIB, combined with the EPM, is used to simulate the failure process of the concrete structure. The simulated results show that the structure’s failure mode and final deformation are critically dependent on the pre-existing crack length and distribution. The simulated load-CMOD curves of the crack and failure modes agree with the results reported in literatures, which suggests that the present method is validated. Since the present constitutive relation of AVIB contains the fracture energy and strength criterion, it simplifies the simulation of crack propagation, avoiding separate facture criterion and mesh reconstruction, etc. It provides an efficient and feasible method for the failure analysis of larger-scale concrete structures with multiple cracks.