Finite element simulation investigation of warping deformation during baking temperature cycle of dissimilar materials sandwich adhesive bonded structures of car body

Adhesive bonding is crucial for joining lightweight, mixed-material car bodies but can cause distortion due to changes in adhesive properties during heat curing. In this paper, based on the characteristics of the roller-hemming structures, a sandwich adhesive bonded structure of aluminum-steel dissimilar materials was designed. A viscoelastic model for the hemming adhesive was developed, and a coupled thermal-chemical-structural model was implemented in ABAQUS. Baking experiments validated the model. Stress and strain variations were analyzed to understand warping mechanisms during the temperature cycle. Further analysis results showed that decreasing heating rate, holding temperature, or increasing cooling rate can reduce deformation.