RESEARCH ON VORONOI-RBSM COUPLED CONCRETE MESO MODELLING METHOD

To overcome the problems of low computational efficiency and limited object size of existing concrete meso numerical simulation methods, a new idea of concrete meso modelling based on Voronoi mesh topology and rigid body spring model (RBSM) is proposed. In this model, concrete is regarded as a two-phase material composed of aggregate and cement mortar. The aggregate is described by Voronoi cell and regarded as a rigid body. The cement mortar is simplified as a uniformly distributed spring at the interface of Voronoi cells. The spring stiffness is automatically defined according to the actual situation of local mortar. It is unnecessary to refine the mesh of aggregate and cement mortar, which allow Voronoi cells to invade and separate at the interface and describe the deformation and cracking of concrete. To verify the effectiveness and applicability of the model, comparative study between indoor tests and numerical simulation was carried out, and the sensitivity of parameters such as the proportion of aggregate was analyzed. Results show that the model can predict the meso mechanical response of concrete members in the loading process more efficiently and accurately and has a good meso simulation effect for smaller concrete specimens and larger reinforced concrete simply supported beams, especially when the mesh size is close to the average particle size of aggregate. In addition, the prediction accuracy of the model is affected by the proportion of aggregate volume. The accuracy of numerical simulation decreases with the decrease of aggregate proportion. Therefore, it is not suitable for meso numerical simulation of concrete materials with high proportion of slurry.