An evaluation of simplified finite element models for spot-welded joints

摘要

Spot-welded joints are widely used in automobile structures. Since a typical vehicle contains several thousands of spot welds, it is often not practical in a vehicle structural analysis to model each and every spot-welded joint in detail. As such, simplified structural models have been proposed in the literature for spot-welded joints in large-scale structural computations. To be adequate, a simplified joint model must be able to produce relevant loading, stress or deformation quantities around a joint that are sufficiently accurate when compared to the results of a more refined model. To this end, the current paper describes the findings of a careful study in which several types of simplified finite element structural models for spot-welded joints are implemented with several mesh refinements and their performance is evaluated against converged three-dimensional finite element models. Various loading conditions and joint parameters are considered. The evaluation is carried out based on comparisons of the structural stiffness of the joint. A detailed error analysis is provided. It is found that most of the simplified joint models and mesh refinements have good accuracy when a joint is subjected to tension, torsion, and out-of-plane bending. However, under in-plane bending and torsion conditions, large errors are introduced even when fine meshes are used.