| 含倾斜裂纹三点弯动态断裂试验研究 |
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| 引用本文： | 郑昌达,杨立云,丁晨曦,陈程,肖成龙,赵勇.含倾斜裂纹三点弯动态断裂试验研究[J].振动与冲击,2020,39(8):165-171. |
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| 作者姓名： | 郑昌达 杨立云 丁晨曦 陈程 肖成龙 赵勇 |
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| 作者单位： | 1.中国矿业大学(北京)力学与建筑工程学院，北京100083；
2.北京科技大学土木与资源工程学院城市地下空间工程北京市重点实验室，北京100083 |
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| 基金项目： | 国家自然科学基金重点项目(51934001);国家自然科学基金面上项目(51974316);校级科研重点项目(BGZYKY201705Z)。 |
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| 摘 要： | 为研究冲击荷载下巷道围岩不同角度径向裂纹的破坏机制,采用落锤冲击加载平台和数字激光动态焦散线实验系统,以有机玻璃为试验材料,设计冲击荷载下半圆孔上不同角度裂纹的三点弯动态断裂试验,记录预制裂纹的角度α的改变对裂纹动态力学行为的影响,通过分析动态应力强度因子和裂纹扩展轨迹的分形维数对实验现象进行归纳总结。研究发现:①预制裂纹角度对裂纹尖端应变能的积累和释放的快慢有较大影响,随着角度的增大,起裂时间变短,起裂更容易,裂纹尖端应变能积累的更快;②裂纹尖端应变能释放的快慢在α=45°两侧表现出不同的规律;③不同角度裂纹的Ⅰ型动态应力强度因子随时间的变化规律具有相似性,但最大值却具有差异性;④不同角度裂纹的扩展轨迹满足一定的分形规律。
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| 关 键 词： | 动态焦散线 冲击荷载 缺陷 动态应力强度因子 裂纹扩展速度 分形维数 |
Dynamic fracture experiments of specimens containing inclined crack under impact load |
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| ZHENG Changda,YANG Liyun,DING Chenxi,CHEN Cheng,XIAO Chenglong,ZHAO Yong.Dynamic fracture experiments of specimens containing inclined crack under impact load[J].Journal of Vibration and Shock,2020,39(8):165-171. |
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| Authors: | ZHENG Changda YANG Liyun DING Chenxi CHEN Cheng XIAO Chenglong ZHAO Yong |
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| Affiliation: | 1.School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China;
2.Beijing Key Laboratory of Urban Underground Space Engineering, School of Civil and Resource Engineering,University of Science and Technology Beijing, Beijing 100083， China |
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| Abstract: | Abstract:In order to clearly investigate the mechanism of radical cracks around a roadway under dynamic loading, dynamic fracture tests of PMMA specimens containing inclined crack were studied by using an impact loading platform of a drop hammer and the test system of digital laser dynamic caustics.The effect of changing the pre-crack angle α on the dynamic mechanical behavior was recorded.Through the caustics method and the fractal dimension method, the results show that: ① The pre-crack angle affects the speed of accumulation and release of the strain energy at the crack tip.As the angle increases, the crack initiation time becomes shorter, crack initiation becomes easier and the strain energy at the crack tip accumulates faster.② The releasing law of the strain energy at the crack tip are different on each side of α=45°.③The tendency of KdI-t is similar, but there is a difference in the maximum.④ The growth trajectory of cracks at different angles satisfies a certain fractal law. |
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| Keywords: | dynamic caustics impact loading flaw dynamic stress intensity factor crack propagation velocity fractal dimension |
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