不同直径空孔对爆生裂纹扩展行为影响规律的实验研究

摘要

In order to obtain the influence of the change of void diameter on the behavior of blasting crack propagation,a dynamic caustic experiment method was used to study the crack propagation path,the propagation velocity and the dynamic stress intensity factor at crack tip under different pore diameters.The results indicate that with the decrease of the relative distance of the three primary cracks in the specimen,the interaction of the crack stress field is gradually enhanced,and the crack propagation velocity increases and reaches the peak value;with the increase of pore diameter,the crack propagation velocity and stress intensity factor oscillation effect are weakened in the later period of crack propagation,which is favorable for the motion cracks to expand toward the cavity;in a certain range,the larger the hole diameter is,the more obvious the guiding effect of the empty holes is on the blasting cracks;with the increase of the empty hole diameter,the trend of dynamic stress intensity factor of crack tip weakens before the three blasting cracks pass through each other.%为得到空孔直径的改变对爆生裂纹扩展行为的影响规律,采用动态焦散线实验方法,研究了不同空孔直径情况下爆生裂纹扩展轨迹、扩展速度及裂尖动态应力强度因子的变化规律.研究结果表明:随着试件中三条爆生主裂纹的尖端相对距离的减小,裂纹尖端应力场的相互作用逐渐增强,使裂纹扩展速度增加并达到峰值;随着空孔直径的增大,裂纹扩展后期裂纹扩展速度和应力强度因子振荡效应减弱,有利于运动裂纹向空孔方向扩展;在一定范围内,空孔直径越大,空孔对爆生裂纹的导向作用越明显;随着空孔直径的增大,三条爆生裂纹在相互贯通之前,裂尖的动态应力强度因子发生突跃增大的趋势减弱.