The Effect of Projectile Nose-Shape on Spot Welding of Steel Plates Using Gas Mixture Detonation Technique

In the present study, deformation pattern in impact spot welded plates with flat and spherical-nosed projectiles using gas mixture detonation set up has been investigated and compared with numerical simulations. The steel plate with a thickness of 4mm was considered as a base plate and steel plates with 1, 2, and 3mm thicknesses were selected as flyer plates and were under direct contact with flat- and spherical-nosed metallic projectiles with a mass of 650 and 1300 gram, respectively. The average velocity of the projectiles was 600 meters per second. The ABAQUS finite element software was used to investigate the high-velocity impact of projectiles on steel sheets. The Johnson-Cook (J-C) model was utilized to describe the behavior of metals. The deformation of plates during the impact spot welding process has been simulated. Comparing the plate deformation pattern in numerical simulation and experimental results found that the numerical model predicted well the deformation of plates during the projectile impact spot welding process. The stress wave propagation on the flyer plates also was studied numerically. The results show that the waves start from the center and progress to the corners of the plate. The values of the equivalent plastic strain (PEEQ) and shear stress pattern for flyers and target plates have investigated as a measure of the quality of welding.