Laboratory study of dynamic fracture for interconnected cracks
YANG Renshu1，SU Hong1，CHEN Cheng1，GONG Yue2，ZHANG Yuantong1
1.School of Mechanics and Civil Engineering，China University of Ming and Technology，Beijing 100083；
2. School of Civil Engineering，Anhui University of Science and Technology，Huainan Anhui，232001
Abstract：In order to study the effect of crack angle on dynamic fracture properties of interconnected cracks under dynamic load, the fracture experiments of three-point bending beam containing pre-cracks were carried out by dynamic caustics test system. Experimental results show that in two interconnected cracks, the wing crack only initiates from the smaller angle branch crack tip under dynamic loading. After one branch crack initiates, another tip stress intensity factor quickly drops down and strain energy redistributes in the specimen. The wing crack of initiation firstly expands along the quasi-vertical direction. The wing crack propagation speed decreases, the path bending degree increases and I - II complex fracture phenomenon is obvious after the wing crack extends to about 2/3 height of the specimen. With the increase of angle between the branch crack and vertical direction, and of branch crack at initiation moment increase but the average speed of the wing crack propagation decreases.
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