Research On Fatigue Behavior Of Adhesive Bonded Structure Based On Cohesive Zone Model

With the rapid development of the automotive industry, people have higher demands for fuel economy of conventional vehicle. Lightweight technology, as the most effective way for improving fuel economy, has received more and more attention in many auto companies. Optimization designing of automobile typical structure is a traditional way of lightweight, beyond that, increasing number of lightweight and high performance materials were used to replaced for common body materials. At the same time, the adhesive bonding technique, as an emerging joining method, has gained important applications as a fast and effective process to connect dissimilar materials in aviation, spaceflight, auto, shipbuilding etc industries because of its advantages over welding, bolting and riveting, such as simple production process, more uniform stress distribution, high fatigue resistance and possibility to keep the integrity of the parent materials.Currently, most studies are mainly surrounding the researches based on the static bearing strength investigation, joint optimization design or theoretical model establishment, besides, there also have scholars did some research on the dynamics of the adhesive joint, however, few people have made any monographic study on fatigue fracture behavior of the adhesive bonded structure under vibration loads ever before.In this paper, the fatigue behavior of adhesively bonded single lap joint mainly subjected to cyclic-vibration-peel (CVP) environment were investigated by using theoretical analyses, numerical simulation and experiment. The combined experimental-numerical approach was developed to characterise the effect of CVP environment on adhesively bonded joints, A damage factor was introduced into a polynomial traction-separation description of cohesive zone model to evaluate the degradation process in the adhesive layer and the stress states in adhesive layer before and after vibration-peel exposure treatment, Carefully designed experimental tests were carried out to validate the simulation results and help the numerical procedure to predict joint mechanical behavior after mechanical fatigue. At last, a new approach called virtual fatigue analysis modeling was proposed for the fatigue analysis of the bonded and riveted car body, the prospect of application for adhesive bonding technology on car body structure were analyzed.