Simulation and analysis of assembly processes considering compliant, non-ideal parts and tooling variations

Variations in parts and tooling are a major problem in automobile body assembly processes. Those discrepancies adversely affect body assembly quality, functionality, cost and time-to-market. Variation simulation analysis has been used in the design stage to predict such uncertainties, but variation analysis based on rigid body assumptions usually yields over-estimates of the assembly variations. This paper presents a new numerical simulation method for the assembly process incorporating compliant non-ideal parts. This method considers the interaction and interference between compliant parts due to part variation, assembly tooling variation, welding distortion, and spring back effects. A butt-to-butt joint assembly example is used to illustrate the effects of various variation causes. A three-parts assembly example examines the assembly and welding sequences. Results from these two examples demonstrate that the proposed method is theoretically sound and practically useful.