An improved numerical modeling for resistance spot welding process and its experimental verification

A numerical model of resistance spot welding with spherical tip electrode is developed to incorporate the electro-thermal aspect as well as thermo-elasto-plastic behaviour inherent in this process. The electro-thermal aspect includes the Joule's resistive heating along the contact surfaces and within the sheet-electrode system due to nonuniform current density distribution in the sheet-electrode. The elasto-plastic deformation of the sheet-electrode interface at higher temperature is included in the thermo-mechanical analysis. The interdependence of those two analyses has been taken care of. The model is used to simulate the spot welding in low-carbon steel sheets of 1 mm and 2 mm thickness and HSLA steel sheet of 1 mm thickness. The results are compared with experimental data obtained hs a part of this work and also with literature data. The comparison has shown an good agreement in all the cases. The results are later used to draw the thermal cycle curves at different location along the faying surface.