CAE driven seam weld optimization for stiffness and fatigue calculations

Structural parts are joined using seam welds, spot welds and bolted connections. The strength and stiffness of any structural part are strongly influenced by the properties of their joints. Seam welds are used extensively in the automotive industry to join panels. The design and the positioning of the seam welds have a significant impact on the technical cost of the project. In the automotive industry, structural optimization and fatigue simulation have become standard applications during any development process. The conventional approach in identifying the position and number of seam welds and its length is time consuming and leads to over design. Current paper highlights developing a simulation process for seam weld optimization in identifying the optimal position and length of seam welds. The optimization workflow is set up in CAE with design objective of minimizing the number of seam welds and finding the optimal length by meeting stiffness targets and fatigue life of seam welds. The design variables considered for this study are the position and length of the seam welds. Design constraints are set for stiffness and fatigue life of seam welds. Design of experiments (DOE) is performed to understand the relation between input and output variables. Based on DOE data, response surfaces are generated for design responses on stiffness and fatigue life targets. Virtual optimization using response surface is performed and final optimized design is identified with optimal seam weld length. Optimized seam weld designs are feasible with CAE workflow, leading to reductions in development time and cost by reducing the number of welds. The case study of seam weld optimization for a battery pack is demonstrated using this process.