Modeling of adhesive layers with temperature-dependent cohesive zone elements for predicting adhesive failure during the drying process of cathodic dip painting

Abstract

The number of electric and hybrid vehicles on the roads has increased significantly in recent years. The high weight of these vehicles requires the use of lightweight construction technologies and materials. In this context, adhesively bonded multi-material structures are increasingly being used. However, the combination of different materials with the production processes established in the automotive industry is a challenge to the manufacturers. Especially the drying process after cataphoretic dip coating can lead to adhesive failure. In order to detect and solve these problems as early as possible, a forecast using the finite element simulation is necessary in the early stage of the project. The objective is to show that a temperature-dependent cohesive zone model can be used to predict damage during the drying process. Therefore, the parameters for such a model were identified on different temperature levels using tubular butt joints, tapered double cantilever beams, and tapered end notched flexure specimens. Finally, the material model was validated on heated lap shear specimens. It could be shown that it is generally possible to predict damage within the adhesive layer using a cohesive zone model. Furthermore, it was shown that the way the stiffnesses are determined has a decisive influence on the calculation accuracy under temperature influence.