爆炸应力波作用下空孔周围裂纹群的扩展规律

In order to explore the extension rule of a crack group around and empty-hole in the stress concentration region under explosion loading, tests, adopting a dynamic caustics system of explosion loading transmission type, were carried out to investigate the dynamic extension behaviors of a prefabricated crack group around an empty hole under the explosion from a single blast-hole. The experimental results show that in the direction of the connection line between the empty-hole and blast-hole, at the meeting-blast side and back-blast side, the prefabricated cracks initiate to expand, while in the rest directions, the prefabricated cracks do not.The length of crack propagation at the back-blast side is longer than that at, the meeting-blast side.The cracks at the meeting-blast side and back-blast side do not start to expand at the same time. The timelag between the two initiationsis about 40 μs. The peak values of velocity and stress intensity factor at themeeting-blast side is larger than those at the back-blast side. The effect of the voids on the crack initiation becomes less and less obvious as the distance L increases. The crack growth velocity and the stress intensity factor at both sides decrease with the increase of L.