Predicting The Strength Of Adhesively Bonded T-joints Under Cyclic Temperature Using A Cohesive Zone Model

With the environment getting worse and worse, the industry of automobile have to take care of the energy saving and fuel economy. To solve the problem of joining heterogeneous materials, lightweight adhesive bonding must be paid the full attention. Because it has a uniform stress distribution, sealing, fatigue durability and so on. Nowadays T-joints are widely used in the automotive industry.This paper is based on the theory of cohesive zone model to analyze the cracks in the adhesive where damage occurred. The cracks including three types:model I,model II and model Ⅲ. We also discussed initial stage of the crack and the crack propagation stage. It also provided a theoretical basis for further FEM analysis below. At the same time this paper also introduces temperature fatigue degradation model (EDM) to simulate the effect of cyclic temperature on the T-joints.The objective of this work is to analyze the effect of cyclic-temperature environment on the adhesive-bonded T-joints. An environmental degradation factor named Deg was utilized in conjunction with cohesive zone model to stimulate the temperature degradation of T-joints. The experimental results showed that long-term cyclic-temperature exposure caused degradation on the ultimate load of T-joints and with the increase of the temperature cycles the ultimate load is gradually decreased. In order to model the adhesive between joint components and simulate the damage propagation, a cohesive zone model based analysis was carried out using finite element method in ABAQUS program. Also, failure process of adhesive can be modeled.