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为了研究纯I和I/II复合型裂纹在冲击荷载作用下的动态断裂行为,基于提出的单裂纹半孔板(SCSC)构型和大直径分离式霍普金森压杆设备,使用2种石材进行岩石的纯I和I/II复合型的动态断裂实验;同时,实验中使用新装置(裂纹扩展计和高速摄影系统)来监测裂纹的扩展速度。为了检验实验结论,基于Drucker-Prager强度模型和累积损伤失效准则,建立针对纯I和I/II复合型裂纹的数值模型,并使用AUTODYN软件来模拟裂纹的扩展行为。总体上,由数值模拟得到的裂纹扩展路径和实验结果十分吻合。研究结果表明,在裂纹扩展的过程中,其扩展速度是一个变化量,甚至有可能停滞,也就是说可能出现止裂现象;同时,CPG和高速摄影系统都可以很好的反映出此现象,并且高速摄影系统更加直观,说明在动态断裂研究中是适用的,同时给出纯I型动态断裂实验裂纹扩展速度特征,供工程参考。
In order to study the dynamic fracture behavior of pure I and I / II composite cracks under impact load, based on the proposed single crack half-hole plate (SCSC) configuration and large diameter split Hopkinson pressure bar equipment, two kinds of stone Dynamic fracture experiments of pure I and I / II composite rock were performed. In the meantime, new devices (crack extensometer and high-speed photography system) were used to monitor the crack growth rate. In order to test the experimental results, a numerical model based on Drucker-Prager intensity model and cumulative damage failure criterion was established for pure I and II / II composite cracks. The software AUTODYN was used to simulate the crack propagation behavior. In general, the crack propagation path obtained by numerical simulation is in good agreement with the experimental results. The results show that in the process of crack propagation, the rate of expansion is a variable or even stagnant, which means that crack arrest may occur. Meanwhile, both the CPG and the high-speed photography system can well reflect this phenomenon, And the high-speed photography system is more intuitive, which shows that it is suitable for the dynamic fracture research. Meanwhile, the crack propagation velocity characteristics of pure I type dynamic fracture experiment are given for engineering reference.