Towards a robust optimization of spot weld design in automotive structures
Résumé
The design of a resistance spot weld distribution for an automobile body-in-white has a strong impact not only on the global system performance but also on the robustness of this performance with respect to uncertainties due to assembly defects and fatigue failures. A quantitative methodology is presented that provides decision-making indicators that allow the analyst to insure a given level of system performance at the cost of performing a quality control of a limited number of welds coming off the assembly line as well as reinforcing a set of critical welds in order to improve the robustness to fatigue failure. In contrast with existing sample-based robustness analyses, the proposed methodology gives visibility to the compromise between improved robustness and higher assembly and quality control costs. In other words, this methodology provides a tool to guide the analyst in the next step to improving robustness while giving an estimation to the cost of the predicted improvement. All examples are presented on a full BIW structure (1,000,000 dofs and 6,500 spot welds)