Numerical study of the mechanism of explosive/impact welding using Smoothed Particle Hydrodynamics method

Metallic explosive welding is a very useful advanced high tech for metals welding and composite production. However, at present, a comprehensive theory which can give an accurate description and prediction of the parameters of explosive welding does not exist. Some investigators considered the welding as a solid state welding process, but others believed that the process is a fusion welding process. The objective of this work is to investigate which theory is more reasonable, in particular to improve understanding of the factors that determine the quality of explosive welded bonds and try to relate the effect of the process variables on the physical parameters. The finite difference engineering package AUTODYN with Smoothed Particle Hydrodynamics (SPH) method has been used in this work, and the phenomenon of jetting and the interfacial waves observed in explosive welding were quite well reproduced in these simulations. The historical changes of shear stress, effective plastic strain of materials were clearly shown in the simulation. It is found that bonding is more likely to be a solid state welding process, however, in some cases, it is likely to be a fusion welding process. The effective plastic strains were greater than the threshold value and the shear stresses were of opposite sign in the simulations of cases where good bonding occurred.