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| Experimental study on the interaction of crack and defects of brittle materials under dynamic loading |
| GAO Guiyun1，2，ZHOU Jie2，LI Zheng2 |
| (1. Institute of Crustal Dynamics，China Earthquake Administration，Beijing 100085，China；2. Department of Mechanics and Engineering Science，College of Engineering，Peking University，Beijing 100871，China) |
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Abstract The study on the interaction of the damage and crack of brittle material under dynamic loading has great importance on the explanation of rock rupture mechanism. The dynamic method of caustics was carried out using polymethyl methacrylate(PMMA) specimens to simulate the interaction process between the crack and defects of brittle materials under dynamic loading. The dynamic crack propagation mechanism，the effects of different types of defects on the crack propagation and the interaction mechanism of crack and defects were discussed. The experimental results show that the crack arrest occurs followed by the increasing or decreasing of crack propagation velocity when there are defects near the crack path. The size of the defects and their distance from the crack path influences the arrest time. The fracture energy consumption increases when there is a circle hole near the crack path，while the multiple holes near the crack tip reduce the crack resistance of crack and the energy consumption. Other type of defects such as the surface crack and the combination of through and surface cracks influence the crack propagation velocity except the energy consumption. The symmetric cracks interact with each other during crack propagation. The minor difference between two symmetric cracks influence the crack initiation and propagation process，and lead to the asymmetric propagation of the two cracks. The crack position，crack propagation velocity，stress intensity factor and energy release rate etc.，can be obtained using the method of caustics which is a promising method for investigating the dynamic interaction between crack and defects.
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2017, Vol. 36 
