S. Jin’s scientific contributions

A new Dopple detection system (DPS) array and a high-speed framing camera are used to test the surface dynamics and local velocity profiles of the expansion, fracture propagation and rupture of TC4 case initiated by high explosive for the research on complex dynamic response of metal case at high-strain rate. The engineering strain at the moment of surface crack initiation and explosion product leakage is estimated through comparative analysis, and the surface crack mode and the influence of crack initiation on velocity profiles are observed. Furthermore, The fracture property of metal case is confirmed from the fracture morphologies of recovered fragments.

Relying on the explosively driven setting of one-end detonator initiation and using the Doppler velocimetry and high-speed framing camera, we diagnosed the expansion and fracture process of the cylindrical shell. The results obtained from our experiment provide the velocity-time history of the shell surface and its dynamic snapshots referring to expansion deformation, crack initiation and propagation, and explosion product leakage. The results from the SPH simulation are in reasonably good agreement with the experimental findings. Systemic analysis of experiments and simulations determine incident angle of shock wave for cylindrical shell, releasing angle of explosion wave, velocity and pressure profile of internal wall and deformed strain, fracture process of cylindrical shell.

One method is offered for calculating small difference of fracture time of cylinder shell in contrast experiments. The fracture strain of cylinder shell was measured by high-speed photography, and simultaneously the velocity-time curve and displacement-time curve were measured by Velocity Interferometer System. The difference of fracture time is calculated by two kinds of measurement results. The difference of fracture time of 45 steel cylinder shell unloaded by JO-9159 and JOB-9003 explosive is 0.45 μs, and the difference of fracture time of W alloy is 0.39 μs. The method can be used to measure more accurately the fracture time of cylinder shell unloaded by detonation.