Identification of the constitutive behaviour of concrete through quasi-static discrete element simulations

The use of a 3D Discrete Element Method (DEM) is proposed to study concrete structures submitted to dynamic loading. The aim of this paper is the correct identification of parameters of the DEM model from usual test results to simulate elastic and inelastic deformation as well as fracture of concrete. A particular growing technique is used to set a densely packed assembly of arbitrarily sized spherical particles interacting together at their contact points, representing concrete. An important difference from classical DEMs where only contact interactions are considered, is the use of an interaction range, which allows the setting of an interaction between two elements not necessarily in contact. The SDEC model exhibits complex macroscopic behaviours such as strain softening, and fracture that arise from extensive microcracking throughout the assembly. The influence on the parameters identification of the assembly size distribution, of the packing, of different geometrical parameters and of the interaction range on the material behaviour is shown. The model produces a quantitative match of strength and deformation characteristics of concrete in terms of Young's modulus, Poisson's coefficient, and compressive and traction strengths.