Study On Mechanical Behavior Of Interference Co-Nection Structure Of CFRP/AL Laminated Members

Carbon Fiber Reinforced Plastics(CFRP)is widely used in civil and military aircraft due to its excellent mechanical properties.The use of aluminum alloys in spacecraft has remained high,and the connection of laminated members is inevitable.The interference connection in many connection methods can improve the joint strength of the composite material and prolong the fatigue life.It is already a relatively mature technology in the connection of metal material components.Based on the above background,this paper studies the stress distribution around the hole of the CFRP/AL laminated member durin g the interference connection,and obtains the stress distribution model of the hole circumference,which lays the connection strength and fatigue life of the interference structure of the laminated member,basis.Firstly,for the CFRP laminate interference structure,the complex potential method of the plane elasticity problem is used to analyze the hole stress and establish a reasonable hole stress distribution model.The modeling and simulation verification was carried out by ABAQUS finite element simulation software,and the perforation stress distribution model of CFRP plate interference connection was obtained.Th en by changing the bolt aperture in the theoretical model,the interference magnitude of the joint structure is changed,and the stress distribution around the bore under different interference quantities is obtained.It is found that the stress distribution shows a non-uniform periodic variation with the change of the circumferential angle of the hole,and the stress peak increases with the increase of the interference amount.The angular position of the hole at the peak of the stress is consistent under different interference quantities.Secondly,for the AL-plate interference connection structure,the complex-body method of the plane elasticity problem is also used to analyze the stress distribution around the hole during the interference fit connection.The corresponding finite element model is built and simulated by AB AQUS finite element simulation software.Verify the consistency of the theoretical model.The perforation stress distribution model when the accurate AL plate interference connection is obtained.It was found that during the interferometric connection of the AL plate,the circumferential radial stress and the circumferential stress were constant at all angles of the hole,and no tangential stress existed.Finally,the CRRP laminate and the AL plate are laminated,and the friction model of the bolt and the plate wall and the interface friction model are established.At the same time,the perforation stress of the CFRP end of the laminated member contact interface is analytically modeled.Through the ABAQUS simulation software,the corresponding finite element model is established and verified by simulation.The accurate stress distribution model of the CFRP end hole at the contact interface of the laminated member is obtained.For the interference connection of laminated members under different interference quantities,the finite element technique is used to study the stress components around the hole of the laminated member in the range of 0°～3 60°,and the stress distribution on the hole wall of the laminated member is analyzed.It is found that the stress distribution at the contact interface of the laminated member interference connection structure is reduced at the angles of the hole circumference compared with the CFRP interference connection structure stress,and the stress peak increases with the increase of the interference amount,but the stress peak appears.The angular position is consistent with the angular position of the CFRP interference connection structure.