An Analysis of the Transient Nugget Formation in Resistance Spot Welds

Abstract

An analytical model is presented to describe the transient nugget growth in resistance spot welds. Since an exact analysis of this model is difficult, due to complexities arising from the interaction of heat and electric current flow, and from the melting of the weldment, an approximate solution is proposed by employing the integral method and some previous results obtained by the authors (13). With the aid of this analysis a simplified nugget growth equation is derived, which can be effectively used for the design of an adequate on-line feedback control algorithm. To verify the validity of this model equation, the computed results are compared with those experimentally obtained for the case of welding of mild steels. The comparison shows that the transient nugget behaviour is well predictable by the proposed model for the welding conditions in this simulation study.