This study was performed to analyze the resistance spot welding process of an aluminum alloy through the numerical simulation ( FEM ) including the electric contact resistance between workpiece and electrode interface and the heat generation in the electrode. The finite element model was developed and used for solving the weld and hold cycles in order to obtain the electro - thermal responses. The resistance of the contact area was represented as the contact element in finite element modelling, and the latent heat effect was included by the fictitious specific heat increase once the melting temperature was attained, but the thermal resistance between the contact area was neglected.
Welding tests of Alclad 2024-T3 Aluminum alloy were made not only to get the input data for the numerical simulation, but also to compare with the numerical results. The data for the contact resistance were determined initially by the contact resistance tests and assumed to decay exponentially up to the solidus temperature. The temperature distributions and dynamic resistance obtained numerically show good agreement with those by tests.
Numerical results reveal that the heat generation in the workpiece contact area is necessary for melting, and Nugget growth depends on the heat generated from the workpiece and its contact area, and the heat from the electrode has a little effect on the Nugget growth, and that from the electrode interface in initially high but decreases rapidly.
