Fracturing behavior around a blasthole in a brittle material under blasting loading

Dynamic fracturing behavior in brittle materials under blasting loading occurs in a very short time. It is usually challenging to observe the behavior experimentally. Therefore, visual observation of the fracturing behavior can be useful information for understanding dynamic fracturing and crack propagation process under blasting loading. In this study, dynamic fracturing behavior under blasting loading was investigated through experimental and numerical methods. Transparent and homogeneous PMMA was used for specimen, while DDNP (diazodinitrophenol) detonators were used to apply blasting loadings. During the blasting experiment, fracturing and crack propagation process were observed using a high-speed camera, then the crack propagation behavior was analyzed in both quantitative and qualitative manners. The results showed that gas-driven fracture in an ear-shape was more predominant than shock-wave-driven fractures. Further, the extent of crack propagation significantly depended on the amount of explosives charge. The experimental results matched well with the analytical solution based on the fracture mechanics theories. A numerical simulation was carried out using a commercial FEM software, which is capable of solving non-linear dynamic problems. The numerical simulation reasonably reproduced the cracking behavior in terms of crack length and orientation which were observed in the experiment.