Simulation of concrete fracture by mesolevel models based on lattice structures

Abstract

Fracture processes in concrete specimens were observed in mesolevel simulations. For generating the composite structure of the concrete in the three‐dimensional space, a new stochastic‐heuristic algorithm has been developed which allows obtaining specimens with comparably high aggregate contents and realistic distribution. The aggregate particles were described as ellipsoids, allowing rigorous control in shape and size distributions. In the structural analyses, the continuum was discretised into lattices of line elements. For the 2D analyses, slice cutouts from the 3D specimen were idealised as planar trusses or frames while for the 3D analyses the specimens were idealised as space structures. In addition, fibre reinforced concrete (FRC) was also modelled by the introduction of additional line elements interconnecting distant nodes of the lattice. Compression, direct tension and wedge‐splitting tests have been simulated by using planar and space truss models. Parametrical study was carried out to investigate the effect of different material properties and proportions in the concrete admixtures. Experimental observations could be confirmed by the simulation results. The applicability and enhancements of such models is further discussed and future research directions are also proposed.