Reconfigurable fixture locating layout for compliant sheet metal welded assemblies subjected to welding force variations

Reconfigurable sheet metal fixtures are used to assemble sheet metal product families of similar locating layouts. These have to maintain locating and clamping layout fidelity for the entire range of a product family. Locating and clamping regions of a sheet metal part tend to dislocate and distort once subjected to nonequalized resistance spot welding guns. The resulted working regions are different in location and size from the original ones. In this article, Monte Carlo simulations are used by the authors to investigate the expected size and location of the working regions of parts in a sheet metal family subjected to random resistance spot welding forces. In the case study, proposed methodology is applied to an available automobile underbody floor panel family. Resulted working regions after the probabilistic deflection analysis are different from the initial ones both in size and location. The results show that by incorporating the random nonequalized clamping forces, the size of the working regions for fixturing elements is increased. Also, the possibility of designing a fixture that cannot assemble the full range of parts is reduced.