摘要
应用透射式焦散线方法,进行了三点弯曲梁的断裂破坏实验。实验采用预置两条垂直于下边界裂纹的有机玻璃试件,在落锤冲击加载下进行断裂实验,着重分析冲击载荷下双裂纹对断裂破坏的影响,获得裂纹扩展的一般规律。实验结果表明:应力强度因子、裂纹扩展速度等动态力学参数不仅与冲击能量、试件形状有关,还与预置裂纹位置及间距有关;裂纹尖端I型动态应力强度因子数值大于II型裂纹,说明I型载荷是裂纹起裂与材料断裂破坏的主要因素;主导裂纹在起裂前后,应力强度因子与裂纹扩展速度呈现波动性增加或下降特征。
The fracture failure experiment of three- point bending beam was carried out by method of transmitted caustics. The specimen was made by polymethyl methacrylate（PMMA） with two preset cracks being perpendicular to the lower boundary. The loading type was falling weight impact. The effect of two preset cracks on fracture failure of specimen under impact load was analyzed, and the aim was to obtain the general rule of crack propagation. The experimental results showed that dynamic mechanical parameters including stress intensity factor（SIF） and cracking speed not only was related to impact energy and specimen shape, but also related to the position of preset cracks and the distance between two cracks. The SIF value of mode I crack was greater than that of mode II crack. It showed that mode I loading was the major factor causing crack initiation and material failure. The value of SIF and propagating speed of major crack present a fluctuant increasing or a fluctuant decreasing before and after initiation of the major crack.
出处
《矿业研究与开发》
CAS
北大核心
2013年第3期28-32,共5页
Mining Research and Development
基金
河南省高等学校青年教师资助计划(2009GGJS-088)
河南省教育厅科学技术研究重点项目资助计划(12A130003)
关键词
焦散线
应力强度因子
裂纹扩展
冲击载荷
Caustic, Stress intensity factor, Crack propaga- tion, Impact load
