Dynamic fracture of metal rods under overdriven effect of cylindrical detonation collision

Abstract

The collision of detonation waves is widely used in weapon design due to its ability to efficiently achieve an ultra‐high pressure region. This work discusses the dynamic fracture of metal rods under the collision of cylindrical detonations. In the experiments, the detonation wave collision is generated by detonating an explosive charge at its end position along two parallel initiation lines, which are detonated by a plane wave generator. The recovered metal rods were broken around their centers due to the superposition of detonation waves. A blue oxidation zone appeared at the fracture surfaces of steel rods in the contact zone under the charge, indicating the local existence of high temperatures. A finite element model was used to simulate and describe the dynamic fracture of metal rods caused by detonation wave collision. The three‐shock theory was used to examine the detonation wave collision. When the incidence angle was between 0° and 40°, the reflected shock wave pressure was approximately 2.1 times the CJ pressure. At an incidence angle of 44.84°, the ratio of Mach and CJ pressure reached a maximum of 3.1. The concentration degree of detonation pressure was developed to evaluate the superposition influence on the dynamic fracture of metal rods. The microstructure of fracture surfaces revealed that metal rods preferred shear fracture under high pressure concentration. With a low degree of pressure concentration, a brittle fracture may emerge. This research serves as a guide for designing and evaluating multimode warheads.