冲击载荷下含空孔三点弯曲梁的动态断裂行为

发布时间：2018-02-22 08:58

本文关键词： 冲击载荷动态应力强度因子动态焦散线空孔　出处：《实验力学》2017年04期 　论文类型：期刊论文

【摘要】：为得到圆孔缺陷对运动裂纹扩展过程的影响规律,采用动态焦散线实验方法进行模型实验,研究了冲击载荷下含空孔三点弯曲梁的动态断裂行为。研究结果表明:空孔对裂纹扩展有极大的阻碍作用,在一定范围内,空孔直径越大,阻碍作用越明显。裂纹扩展到空孔附近时,扩展速度会下降。裂纹在空孔上部再次起裂后,最大扩展速度远远大于裂纹与空孔贯通前的最大扩展速度。裂纹扩展至空孔附近时,裂纹尖端动态应力强度因子KdⅠ和KdⅡ均会下降。裂纹在空孔上部再次起裂后,裂尖的应力强度因子KdⅠ和KdⅡ均大于裂纹与空孔贯通前裂尖的KdⅠ和KdⅡ。在整个扩展过程中,裂纹尖端的动态应力强度因子KdⅡ远小于KdⅠ,说明KdⅠ在裂纹扩展过程中起主要作用。
[Abstract]:In order to get the influence of hole defect on the movement process of crack propagation, using dynamic caustics method of model experiment, the dynamic fracture behavior was studied under impact load with an empty hole of three point bending beam. The results show that: the empty hole on the crack propagation are greatly hindered by, in a certain range, the air hole diameter the greater obstacle is more obvious. The crack to the empty hole near, propagation velocity will decrease. Crack again in the empty holes on the upper part, the largest expansion rate is far greater than the maximum expansion rate of empty hole and the crack front. Near the crack to the empty hole, crack tip stress intensity factor Kd 1 and Kd II declined. Crack again in the empty hole in the upper part, the crack tip stress intensity factor Kd I and Kd II were greater than the empty hole and crack before the crack tip of Kd I and Kd II. In the whole process of the extension of dynamic crack tip The stress intensity factor Kd II is far less than that of Kd I, indicating that Kd I plays a major role in the process of crack propagation.

【作者单位】：中国矿业大学(北京)力学与建筑工程学院;
【基金】：国家自然科学基金面上项目(51374210)资助开放自然基金面上项目(KFJJ17-01M)资助
【分类号】：O346.1

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