爆炸应力波与裂纹作用实验研究

为研究爆炸应力波与裂纹相互作用机理,利用透射式爆炸动态焦散线光学实验系统研究了预制水平静态裂纹和切缝药包炮孔爆破产生的水平运动裂纹受正入射爆炸动载作用后动态特性的变化规律。结果表明:正入射爆炸应力波与静止裂纹作用时,爆炸应力波P波使得裂纹先闭合后张开,S波在裂纹壁面形成波浪状散斑上下交替向外扩展;运动裂纹尖端应力场对静止裂纹的起裂和扩展有重要影响。后爆孔爆炸应力波对先爆孔产生的水平定向运动裂纹尖端动力学特性影响显著。当爆炸应力波与运动裂纹同向时,P波使得裂纹扩展速度和应力强度因子KI^d先减小后增大,S波促进了裂纹的扩展,波与裂纹作用之后,裂纹扩展速度增大;当爆炸应力波与运动裂纹反向时,P波抑制了运动裂纹的扩展,波与裂纹作用之后,裂纹扩展速度和应力强度因子KI^d均逐渐降低。

Interaction between blast stress waves and cracks

In this paper we investigated the interaction mechanism between blast stress waves and cracks,and examined the variation of the dynamic characteristics of prefabricated horizontal static crack and horizontal motion crack produced by a split-tube holder charge under the normal incidence blast stress wave using the transmitted explosion dynamic caustics optical experiment system. The results showed that when the normal incident blast stress wave interacted with the stationary crack, the P wave causes the crack to close and then open, and the S wave formed a wavy speckle on the crack wall surface and the speckle alternately expands up and down along the stress wave propagation direction. The stress field surrounding the moving crack tip exerted a significant influence on the crack initiation and propagation of the static cracks. The blast stress wave generated by the post-explosion blasthole had an obvious impact on the dynamic characteristics of the horizontal directional motion crack produced by the first blasthole. When the direction of the propagation of the blast stress wave coincided with the direction of the propagation of the moving crack, the P wave causes the crack propagation velocity and the stress intensity factor KI^d to decrease at first and then increase, the S wave promoted the crack propagation and the crack propagation was strengthened after the wave-crack interaction. When the direction of the propagation of the blast stress wave was opposite to the direction of the moving crack propagation, the P wave suppressed the expansion of the moving crack, and the moving crack propagation velocity and the stress intensity factor KI^d were gradually reduced after the wave-crack interaction.