爆炸应力波作用下动、静裂纹相互作用的实验研究

采用数字激光动态焦散线测试系统，研究爆炸应力波作用下动裂纹与预制静裂纹(水平夹角为90°、150°)相互作用机理，以及裂纹扩展的动态行为。结果表明:(1)在动、静裂纹贯通之前，静裂纹两端便出现焦散斑，动、静裂纹贯通以后，静裂纹沿爆炸应力波传播方向扩展，并且扩展速度小于动裂纹扩展速度，也小于无静裂纹时动裂纹扩展速度; (2)静裂纹存在时，动裂纹扩展的总体长度减小。动裂纹起裂时间缩短，扩展速度基本不受静裂纹的影响，裂纹应力强度因子值大于静裂纹两端值; (3)随着静裂纹水平夹角的增大，动、静裂纹贯通时动裂纹沿水平方向偏转距离增大，静裂纹B端反向扩展与动裂纹相互“咬合”，C端裂纹扩展位移和速度增大。

Dynamic and static crack interaction under action of explosive stress wave

This paper studied the interaction mechanism between the dynamic crack and the precast static crack (horizontal angle for 90° and 150°) under the action of explosion stress and the dynamic behavior of crack propagation using the digital laser dynamic caustics test system.The results show that before the dynamic crack and static crack coalescence,the caustics speckles will occur at both ends of the static crack,while after the dynamic crack and static crack coalescence,the static crack extends in the horizontal direction with a speed lower than that of both the dynamic crack and the crack expansion without static crack;that when the static crack exists,the overall length of the dynamic crack expansion is reduced,the crack initiation time is shortened,the expansion speed is not affected by the static crack,and the stress intensity factor of the crack is greater than that of the static crack;and that as the horizontal angle of the static crack increases,the deflection distance of the dynamic crack increases along the horizontal direction when the dynamic crack and the static crack become coalescenced,end point B of the static crack expands towards the opposite direction,ending in "mutual occlusion" with end point C of the dynamic crack as the displacement and velocity of the latter's expansion increases.