Simulation experiment of rock fracture containing inclined edge crack under impact load

In order to simulate fracture behavior of rock under different angles between pre-crack and loading direction,the fracture experiments of the three-point bend beam containing unilateral incision subjected to impact load were carried out by transmission-type caustics test system.Experimental results show that inclined edge crack specimen is subjected to normal stress and shear stress.The growth cracks are mixed code cracks and the focal speckles at the tips of crack are also mixed.The dynamic stress intensity factor,crack propagation time and the crack propagation velocity are associated with the angle changes between pre-crack and the loading direction.As the angles between pre-crack and the loading direction increase,the maximum of crack propagation speed increases,and the oscillation of the crack propagation velocity also increases.When the loading direction is the same as the pre-crack direction,the crack initiates the fastest,and the crack is the Ⅰ-type crack.As the angles between loading direction and pre-crack direction increase,the crack takes on mixed characteristic,the dynamic stress intensity factor KⅡd represents more obviously and its value increases.