Experimental and numerical study on the dynamic fracture of flattened Brazilian discs with prefabricated cracks

A split Hopkinson pressure bar system was used to apply a high-speed dynamic load to a flattened Brazilian disc, and the dynamic characteristics of purely type-I or -II fractures or mixed type-I-II composite fractures were studied in detail. The effect of the strain rate and the inclination angle of the prefabricated cracks was analyzed and compared with theoretical results. Furthermore, a dynamic three-dimensional numerical model was developed on the basis of the mesoscopic nonuniform distribution of materials. The failure process, failure pattern and acoustic emission performance of the disc were observed step by step in the numerical simulation. The experimental and numerical results were in good agreement and showed that the strain rate and inclination angle affected the strength, failure pattern and toughness of the dynamic fracture. This study contributes to numerical simulation in which the failure process of secondary cracks was well presented by introducing mesoscopic nonuniformity into the model.