The aim of this study is to explore the fracture dynamic properties of defect bodies under explosion loading by using the system of digital laser dynamic caustics test. The propagation of directional cracks and the fracture process of defect bodies have been observed by high-speed camera, as well as analyzed for the changing rules of speed and stress intensity factors when the directional crack was close to defect. Experimental results found that the defect has an inhibitory effect on the spreading of cracks when the detonation crack is extended toward the defect. With the decrease of the curvature of the elliptical defect, the energy accumulation rate decreases with the decrease of the curvature in the process of the generation of the cracks at the endpoints of wings, and its fracture toughness increases with the decrease of the curvature, and when the curvature is reduced to a certain extent, the wing crack cannot crack. The dynamic stress intensity factor of the crack tip has a positive correlation with the velocity of cracking, within a certain range. The fracture toughness of the crack at the time it begins is larger than during its spreading.
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