Research On Parameters And Dynamic Performance Of AA5182-CFRP Adhesive Joint For Vehicle Body

With the development of lightweight vehicles,lightweight materials su ch as aluminum alloy,carbon fiber reinforced plastics(CFRP)and high-strength steel are increasingly used in automobiles.The widespread use of lightweight materials has led to problems with the connection of different materials.Welding,riveting,etc.have certain limitations in connecting metals and composite materials.A dhesive bonding technology can connect dissimilar materials without damaging the connection part and it is widely used in automotive industries.In this paper,lightweight aluminum alloy AA5182 and carbon fiber reinforced plastics T300 are selected,which are connected by bonding technology.The influence of process parameters on mechanical properties,dynamic performance and micro-failure behavior and failure mechanism of joints are investigated.Firstly,the preparation process of the bonded joint was determined.The influence of the joint parameters on the strength and failure behavior of the bonded joint was studied.The results show that for aluminum/CFRP single lap joints,as the length of the overlap increases,the maximum load increases.The thickness of the aluminum plate also has a certain influence on the strength of the adhesive joint.As the thickness of the aluminum plate increases,the maximum load increases.The failure mode of the joint changes from the failure of the Al plate break to the cohesive failure.Secondly,the shear performance and failure mode of aluminum/CFRP single lap joints at different shear velocities were studied.The failure mechanism was analyzed by digital image correlation technology.The results show that the shear strength of the bonded joint is affected by the shearing speed.As the shearing speed increases,the shear strength of the bonded joint increases.The failure mode is mix-mode failure at different shear speeds,but the area proportion of cohesive failure and carbon fiber failure is different.DIC analysis shows that the strain value is bigger at the edge of the bonding area and the cracks generated from here.Finally,the fatigue properties of aluminum/CFRP single-lap joints were studied,and the fatigue life of the joints under different stress levels was obtained and the S-N curve was fitted.The results show that under the low stress level,the fatigue performance of the bonded joint is excellent.and the failure behavior is the mixed failure mode of the Al plate failure and cohesive failure,and the fatigue cycle life is more than 5×10~6 times.At high stress levels,the fatigue life of the joints decreases rapidly,and the failure mode is mainly the cohesive failure.At the same time,the displacement analysis of the joint during the fatigue process shows that the displacement change of the joint is not obvious during the cycle.Most of the fatigue cycles of the joint during the fatigue cycle are used to generate the initial crack.The displacement increases rapidly after the crack is generated and then joint fails.