Resistance spot welding process simulation for variational analysis on compliant assemblies

• Improved spring-back evaluation with a plastic material model in tolerance stack-up.
• Loading sequence and interference conditions due to geometrical errors are considered.
• Initial deformations due to fixture closure are considered.
• The material melting in the weld nugget reduces the elastic energy available for springback.
• The method is able to consider many welding points and is sensible to the welding sequence.

This work proposes a methodology that can be used to define a FEM simulation of the body welding process with the aim of evaluating compliant assembly deformations and spring-back, considering the effect of material plasticity, in order to improve the results of variational analysis methods, which so far have been based on a linear elastic material model. With reference to the automotive field, the simulation considers the effects of fixturing and resistance spot welding applied to sheet metal parts subjected to dimensional and geometrical tolerances.