A dynamic FEM-DEM multiscale modeling approach for concrete structures

Abstract

The dynamic behavior of concrete is strain-rate-dependent, which affects the failure modes of structures. In this study, a multiscale modeling approach is developed for concrete structures under dynamic loading, which couples the macroscale finite element method (FEM) and the mesoscale discrete element method (DEM). The dynamic response of structures is analyzed using the macroscale FEM, and a representative volume element (RVE), composed of aggregate, mortar, and interface, is simulated using the mesoscale DEM to capture the strain rate effects of concrete. By fully taking the advantages of macroscale and mesoscale simulations, it is no longer essential to use complex constitutive laws or input rate-dependent parameters for the macroscale FEM modeling because the concrete fracture can be explicitly illustrated through the breaking process of the mesoscale RVE. This approach is applied to concrete beams and the Koyna dam to verify its applicability. These practical comparisons demonstrate that the seismic tensile strength increases with the strain rates under seismic loading and that the actual repeated crack-closure process of concrete is adequately simulated by the proposed method.