Study On Mechanical Properties Of Bonded Joints Of Carbon Fiber Reinforced Plastics Under Impact Loading

With the increase of automobile production and sales,energy security has become an important problem in the automobile industry.Energy conservation and emission reduction has become an important research direction in the development of the global automobile industry,and the lightweight of automobile materials is an important way of automobile energy saving and emission reduction.Carbon fiber reinforced polymer(CFRP)has many advantages,such as high sti ffness,specific strength and excellent fatigue resistance.It has been widely applied in automotive field.In engineering practice,the composite structure needs to be manufactured and assembled again,so the connection between composite materials is very important.Traditional mechanical connections need to be cut and drilled,which will damage and weaken the properties of composite materials.Therefore,composite materials are more suitable for bonding.Based on this background,this paper studies the im pact mechanical properties of HTS40/977-2 carbon fiber laminates single lap adhesive joints.First,on the basis of the experiment,the carbon fiber composite laminates are simulated and the low velocity impact model of carbon fiber composites is establish ed in the finite element software ABAQUS.Cohesive unit,viscous contact and Tie contact were used to simulate the interlaminar relationship of CFRP laminates.Compared with the experimental results,the modeling method of the relationship between the cohesive unit simulation layer is most matched with the experimental results,and the rationality of the material parameters and the established finite element model is verified.Secondly,based on the determination of material parameters and modeling methods,the low-speed impact process of carbon fiber composite adhesive joints is numerically simulated.Considering the impact of the adhesive layer properties on the impact performance of the joint,three kinds of adhesive layers with different toughness were used to connect the joint,and the damage degree of the adhesive bonding was gradually reduced with the increase of the toughness of the adhesive.Considering the uncertainty of the punch shape in practical engineering application,the impact of the punch shape on the impact performance of the joint is studied.The impact joints of the hemispherical shape,the sharp head and the conical punch are used respectively.Finally,the joint connection of different materials was studied.The numerical simulation of the low velocity impact response of the joint joint of carbon fiber laminates and iron and aluminum was carried out,and the impact of each dissimilar material joint under two operating conditions was impacted by carbon fiber laminates and metal materials respectively.The failure modes and energy absorption of the joint are compared.Meanwhile,the lightweight cost of the three materials is compared.The results show that when the carbon fiber composite / metal bonding joint bears the impact load,when the carbon fiber is on the impact,when the energy of the punch reaches a certain threshold,the energy of the punch increases and the maximum contact force does not change obviously.When the metal is on the punch,the failure degree of the rubber layer is high,and the energy absorbed by the joint is also increased.The research in this paper can provide a reference for the design and analysis of composite adhesives.