The robustness of dynamic vehicle performance to spot weld failures

Spot welds are the dominant joining method in the vehicle assembly process. As the automated assembly process is not perfect, some spot welds may be absent when the vehicle leaves the assembly line. Furthermore, spot welds are highly susceptible to fatigue, so that a substantial number may fail during the vehicle lifetime. The scope of this paper is twofold. First, the impact of spot weld quality and design on a vehicle's functional performance is reviewed, addressing strength and stiffness, NVH and durability as performance attributes. The overview briefly covers both experimental tests and predictive finite element modeling approaches. Second, an industrial robustness study is presented that assesses the effect of spot weld failure on dynamic vehicle characteristics. Damaged models are generated automatically by breaking a subset of the vehicle's spot welds, using a (weighted)-uniform selection probability. Monte Carlo simulations are then used to assess the scatter on dynamic vehicle characteristics.