A Heterogeneous Cohesive Crack Model for Quasi-brittle Materials Considering Spatially Varying Random Fracture Properties

摘要

This study develops a heterogeneous cohesive (HC) crack model to predict macroscopic fracture in quasi-brittle materials considering meso-scale random fields of fracture properties. By characterizing spatially-varying fracture properties as Weibull random fields and using a remeshing procedure, heterogeneous cohesive crack propagation is simulated to predict more realistic crack paths and to more reliably assess macroscopic load-carrying capacity A new criterion to determine the crack growth direction is developed by taking into account both the crack-tip stress state and heterogeneity of the tensile strength. A concrete beam subjected to mixed-mode fracture is modelled as a benchmark example The numerical simulations reveal that crucial fracture phenomena, such as the tortuousness in crack trajectories, can be effectively captured by the HC model. Effects of various important parameters on the crack paths, peak loads, structural ductility and overall reliability, including the variance of random fields and the shear fracture resistance, are investigated and discussed.