含圆孔缺陷三点弯曲梁动态焦散实验  

Dynamic Caustics Experiment of Three-point Bending Beam with Circular Hole Defect

作　　者：岳中文[1] 王煦[1] 许鹏[1] 宋耀[1] 杨惠斌[1] 

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：《实验力学》2015年第3期339-347,共9页Journal of Experimental Mechanics

基　　金：国家自然科学基金面上项目(51374210);国家自然科学基金重点项目(51134025);中央高校基本科研业务费资助(2009QL15);高等学校学科创新引智计划资助(基地编号:B14006)

摘　　要：应用新型数字激光动态焦散线实验系统,采用含预制裂纹的有机玻璃板试件进行落锤冲击实验,研究了含圆孔缺陷三点弯曲梁的动态断裂行为。通过实验得到了含圆孔缺陷三点弯曲梁裂纹尖端动态应力强度因子的变化情况、裂纹扩展速度的变化情况以及裂纹贯穿空孔的扩展情况等。实验结果表明:三点弯曲梁中的空孔位置对裂纹的扩展轨迹具有明显的导向作用;空孔位置的改变会影响三点弯曲梁的断裂时间;空孔位置的变化对空孔下方裂纹的扩展时间、扩展轨迹影响较小;在空孔位置居中的情况下,空孔上方裂纹的最大扩展速度大于空孔位置偏移时的情况。Drop hammer impact test was carried out to study the dynamic fracture of three-point bending beam with circular holes defect by applying a new digital laser dynamic caustics experimental system and adopting methyl methacrylate plate specimens containing precrack.Through experiment,the evolution of dynamic stress intensity factor at the crack tip of three-point bending beam with circular holes defect,the change of crack propagation rate and crack running through empty hole etc were all obtained.Experimental results show that the empty hole location in three-point bending beam plays a significant guiding role for crack extension trajectory;the fracture time of three-point bending beam is affected by empty hole location;the position change of empty hole has less effect on the crack propagation and extension trajectory of crack underneath hole;in the case of an empty hole is centrally located,maximum extension velocity of crack above the hole is faster than that of centrally located empty hole.

关 键 词：三点弯曲梁 空孔 冲击荷载 焦散线 应力强度因子 

分 类 号：O346.1[理学—固体力学]