正入射爆炸应力波与运动裂纹作用的动态光弹性实验研究

Dynamic photoelastic investigation of interaction of normal incidence blasting stress waves with running cracks

采用动态光弹性实验方法,研究了正入射爆炸应力波对运动裂纹的作用效果。实验得到了运动裂纹与正入射爆炸应力波作用过程的光弹等差条纹变化图,分析了正入射爆炸应力波对运动裂纹尖端动态应力强度因子和裂纹扩展速度的影响效果,以及正入射爆炸应力波对运动裂纹扩展轨迹的影响。研究表明:正入射爆炸应力波对运动裂纹扩展方向没有明显影响,但对运动裂纹尖端动态应力强度因子和裂纹扩展速度有显著时间相关性的抑制和增强作用;当正入射爆炸应力波P波前端压缩脉冲相与运动裂纹相互作用时,裂纹扩展速度和裂纹尖端应力强度因子会受到抑制;当正入射爆炸应力波P波尾部拉伸脉冲相和S波与运动裂纹相互作用时,裂纹扩展速度和裂纹尖端应力强度因子则得到显著增强。

Dynamic photoelasticity was utilized in an experiment to study the interaction of normal incidence blasting stress waves with a running crack.Photoelastic isochromatic fringe pattern of the interaction of normal incidence blasting stress waves with a running crack was obtained.Experimental data were analyzed to study the effect of the normal incidence of stress wave on the dynamic stress intensity factor,crack propagation velocity and crack growth trajectory at the crack tip.The results indicate that the normal blasting stress wave has no effect on the propagation direction of crack,but it has a significant time-dependent inhibition or enhancement effect on the dynamic stress intensity factor and velocity of the crack tip.The crack propagation velocity and the stress intensity factor at the crack tip are suppressed when the forward impinging P wave front compressive pulse phase interacts with the running crack.The crack propagation velocity and the stress intensity factor at the crack tip increase when the normal incident P wave tail ten-sile pulse phase and S wave interacts with the running crack.