Static and dynamic concrete calculations: Breakable aggregates in DEM model

Michał Nitka

doi:10.1016/j.jobe.2024.109006

Static and dynamic concrete calculations: Breakable aggregates in DEM model

Abstract

The paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic stress-strain curve, crack propagation, the number of broken contacts, and the distribution of forces and stresses. Special attention was given to micro-fracture and cracking. The calculations were performed using the discrete element method (DEM) and were limited to a 2D problem. The proposed model introduced the consideration of aggregate breakages, which is a novel aspect compared to our previous computations. Fragmentation of the aggregate is particularly important in dynamic tests due to the release of higher energy. Finally, a beam with weak aggregate was used to validate the effectiveness of the model.