含预制裂纹悬臂梁的动态断裂试验研究  

Dynamic Fracture Experimental Study on Cantilever Beam with Prefabricated Cracks

作　　者：李清[1] 薛耀东 刘涛[1] 于强[1] 钱路[1] 朱各勇 

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《科学技术与工程》2018年第1期309-314,共6页Science Technology and Engineering

基　　金：国家自然科学基金(51374212);国家大学生创新训练项目资助

摘　　要：针对含预制裂纹的悬臂梁,利用动态焦散线试验系统,研究在冲击载荷下悬臂梁的动态断裂问题;以及裂纹尖端动态应力强度因子、裂纹扩展位移、速度、加速度的变化规律。结果表明,含单一上边界直裂纹构件先于含单一上边界斜裂纹构件达到动态断裂韧度,试件发生破坏;含单一直裂纹的试件断裂模式为Ⅰ型,含斜裂纹试件的断裂模式为Ⅰ-Ⅱ复合型,且曲裂程度大于含直裂纹的试件;含斜裂纹试件的裂纹扩展速度最大值大于含直裂纹的试件,且速度的振荡性较强;斜裂纹的存在造成加速度的振荡变化较大,能量释放的不均性加强。研究结论为揭示含预制裂纹悬臂梁的动态破坏规律提供了指导意义。Aiming at the cantilever beam with prefabricated crack,the dynamic fracture of the cantilever beam under the impact load and the dynamic stress intensity factor,the crack propagation displacement,the velocity and the acceleration of the crack tip are studied by using dynamic caustic test system. The results show that specimen with a single upper boundary vertical crack member is preceded by a single upper boundary oblique crack member to achieve dynamic fracture toughness and was destroyed; the fracture pattern of specimen with single vertical crack is typeⅠ,and the fracture mode of specimen with oblique crack is Ⅰ-Ⅱ compound type,and the degree of cracked is larger than that of specimen with vertical crack; the maximum crack propagation velocity of the specimen with oblique crack is larger than that of the specimen with straight crack,and the oscillation of velocity becomes obvious.The presence of oblique cracks causes the oscillations of acceleration to vary greatly,and the nonuniformity of energy release is enhanced. The conclusion is to provide guidance for dynamic damage law of cantilever beam with prefabricated crack.

关 键 词：预制裂纹 冲击荷载 悬臂梁 裂纹扩展 动态焦散线 

分 类 号：TU317.3[建筑科学—结构工程]