Simulation and sensitivity analysis of controlling parameters in resistance spot welding

This study was performed to investigate the fundamental parameters controlling the nugget growth. The parameters were categorized into four groups, i.e. material parameters, electrical parameters, thermal parameters and geometrical parameters. In order to quantify the sensitivity of nugget growth to changes in these parameters, a numerical model which incorporates the electrical, mechanical and thermal contact was developed. As a result, a sensitivity index table was constructed and analyzed to ascertain the relative importance of these characteristic parameters. It was found that the most important factor in determining the variability of nugget growth behavior is the ratio of contact radius to electrode radius and the ratio of electrode radius to the square of specimen thickness. In general for a variation of 10%, the geometrical parameters are most important, followed by the material parameters. The electrical parameters and the thermal parameters are the least important. The importance of contact at the faying interface is greater for the contact area than for the contact resistance.