Numerical Modelling of Resistance Spot Welding of Aluminium Alloy.

Abstract

An electro-thermal and mechanical coupled model is reported for analysing resistance spot welding process of aluminum alloys using curved face electrodes. An in-house software is developed based on finite element method that can predict in-process growth of nugget diameter, penetration and electrode-sheet contact diameter for different combinations of welding current, weld time, electrode force. Non-linear, temperature-dependent, thermo-physical material properties as well as latent heat of fusion/solidification have been considered. An exponential decay of initial contact resistance is considered with different values of initial contact resistance for different surface conditions of aluminium alloys. It is observed that the formation of weld nugget is completed within the very first cycle considering a 50 Hz AC power supply. Increase of welding current enhances the area of molten zone substantially. Change in the initial value of contact resistance does not influence the overall nugget zone significantly. Overall, the present work indicates that such a simulation model can be very useful as an off-line monitoring tool to estimate the influence of process parameters on the final weld dimensions.