冲击载荷下双预置裂纹三点弯曲梁动态断裂实验

采用数字激光焦散线实验系统,对双预置裂纹三点弯曲梁进行了动态冲击实验,分析了双预置裂纹对试件裂纹尖端扩展速率和动态应力强度因子值的影响。实验结果表明:1双预置裂纹三点弯曲梁在动态冲击实验中,B裂纹作为开裂裂纹,其起裂时间和扩展速率峰值受到冲击载荷加载点与其预置位置之间水平距离值的影响,距离越小,起裂越快,扩展速率峰值越大;2试件开裂后,裂纹的裂纹扩展速度和动态应力强度因子值随时间的变化曲线均具有快速上升然后波动下降的规律;3B裂纹起裂所需能量随着A、B裂纹间距a值减小而增大。

A dynamic fracture experiment of a three-point-bend beam containing double pre-existing cracks under impact load

A dynamic impact experiment of a three-point-bend beam containing double pre-existing cracks was performed by using a digital laser dynamic caustics experimental system,and the influence of double pre-existing cracks towards the specimen’s propagation velocity and the dynamic stress intensity factor (DSIF) was studied. The experimental results are: ① during the dynamic impact experiments,the initial cracking time and maximum propagation velocity value of B crack,which is the growing crack,decline as the horizontal distance away from loading point; ② after the cracking happens,curves of propagation velocity and DSIF along with time both follow the rules of increasing rapidly and declining with fluctuation; ③ the energy that B crack requires to initiate is enhanced as the distance between A and B cracks increases.