Development of high-efficiency modeling technique for weld-bonded steel joints in vehicle structures—Part I: Static experiments and simulations

To develop an effective modeling technique for weld-bonded structures, fundamental experimental studies, including adherend and adhesive tests, and static tests with spot-welded, adhesive-bonded and weld-bonded coupons, were carried out. These studies reveal the brittle nature of the epoxy-adhesive-bond and the ductile rupture characteristic of the spot-weld pull-out. In the failure process of a weld-bonded structure, the adhesive-bond and the spot-weld fail at different stages and have little coupling effect, but they supplement each other.A modeling strategy was devised and implemented based on the static experimental findings and an assessment of available modeling approaches in a finite-element analysis program. As a result, a combination of the constrained spot-weld (CSW) model and the mesh-independent spot-weld (MISW) model is recommended for modeling the deformation and failure of weld-bonded vehicle structures. An approach for calibrating the failure parameters in the failure criteria is also developed. The recommended modeling method renders satisfactory correlation between simulations and tests at the static coupon test level and acceptable time-step for full-vehicle crash simulations.