Damage accumulation in quasi-brittle fracture

The strength of quasi-brittle materials depends on the ensemble of defects inside the sample and on the way damage accumulates before failure. Using large scale numerical simulations of the random fuse model, we investigate the evolution of the microcrack distribution that is directly related to the strength distribution and its size effects. We show that the broadening of the distribution tail originates from the dominating microcracks in each sample and is related to a tendency of crack coalescence that increases with system size. We study how the observed behavior depends on the disorder present in the sample.