分野別セミナー

Fracture propagation and damage evolution is extremely important for many industrial application including mining industry, composite materials, earthquake simulations, hydraulic fracturing. In this project a numerical damage model is applied to an isotropic sandstone specimen containing a pre-existing 3-D surface flaw in different configurations under uniaxial compression. The heterogeneity of rock is considered by assuming the material properties in rock can be represented by a Weibull distribution. We investigate the effect of parameters including the heterogeneity of the elastic moduli and geometry of the single flaw on the stress strain response. The generation of three typical surface cracking patterns, called wing cracks, anti-wing cracks and far-field cracks were identified and these depend on the geometry of the pre-existing surface flaw. The numerical fracture simulation of rock specimen by using eScript software and finite element method is presented. This project will also develop anisotropic damage models for fracture propagation which will be coupled to porous media flow models to build hydraulic fracture simulators that include key factors such as the cleated nature of the coal seam, pre-existing joints and faults, in-situ stress and surrounding stratigraphy of the coal seams. Completion of the model will advance our understanding of fracture growth in heterogeneous cleated coal and help to develop fracture simulators that can be applied to both unconventional and conventional oil and gas reservoirs.