EXPLOSIVE WELDING SIMULATION OF MULTILAYER TUBES

Summary. Explosive welding is a process which uses explosive detonation to propel the flyer plate material into the base material to produce a sound joint. Experimental tests have been performed to explosively welded aluminum 5056, aluminum 1015 and stainless steel 304 tubes in one step. The tests have been carried out using various stand-off distances and explosive ratios. Various interface geometries have been obtained from these experiments. In this study, all the experiments carried out were simulated using the finite element method. The Williamsburg equations of state were used to describe the behavior of explosive. The Williamsburg equations of state have been previously developed for low explosive mixture. These equations were coded into the FEM software. The Johnson-Cook constitutive equations were used to model the behavior of tubes. The Williamsburg equation of state parameters and Johnson-Cook constitutive equations constants were obtained by experiments. Most aspects of the explosive welding parameters were properly simulated. The flyer plate and collision velocities obtained from the analysis were validated by the pin-measurement experiments. The numerical results showed that very high localized plastic deformation produced at the bond interface. The temperature at the interface just after impact was predicted to be lower than the melting temperature of both materials, but high enough for phase changes to occur, i. e. similar to what happens in tempering or martensetic formation in steels. This temperature increase is of very short duration and drops after the impact