Researchers from Magna Steyr (link) investigated optimization of weld spots with respect to stiffness and fatigue. CHEXA elements were used in some runs to represent spot welds, and in some cases node to node beams were used. A cantilever was optimized and both fatigue and stiffness optimized weld distribution showed an even distribution of fatigue damage. No big difference in stiffness was observed, as the sheet metal provides almost all the stiffness in this loading mode. Another optimization was carried with a car body in white model (apparently Audi A3). All the weld spots were optimized. The design space is a rather interesting cloud of spot welds, as visualized in one of the pictures.
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