Fracture in heterogeneous materials: experimental and theoretical studies

The kinetics of fracture in stressed heterogeneous materials is investigated in a differentiated way using the parameter Δt, the interval between single or multiple (cooperative) microfracture events recorded by acoustic emission (AE) responses. The patterns of fracture nucleation and growth, which is a statistic process, are controlled by the heterogeneity of deforming material. There are two important aspects revealed by the study: 1) structural heterogeneity of materials causes uneven distribution of stress in loaded solids and thus creates local zones of microstress and ensuing microfracture in the overstressed zones; 2) AE measurements and microseismic monitoring are applicable to prediction of fracture by locating its source and thus allows predicting related hazard in mines, tunnels, bridges, nuclear-power plants, and other important engineering objects.