Self-inserting Adhesive Bonding And Mechanical Properties Of GFRP Laminates

As a new material,owing to light weight and high strength,composite materials are widely used in aviation,aerospace,navigation,construction,automotive industry and so on.The connection mode of composite materials has become a research hotspot at present.The existing methods of composite material connection include cemented connection,mechanical connection and hybrid connection.Mechanical connection includes rivet connection,bolt connection and fastener connection.Its advantages are safety and reliability,small strength dispersion,large load transmission,easy handling,etc.Its disadvantages are stress concentration caused by opening,low connection efficiency,increasing the weight of fasteners or rivets,etc.With the advent of high-performance adhesives,cemented joints have been widely used in engineering due to their advantages of light weight,high strength,high connection efficiency,anti-corrosion,anti-electromagnetic interference and so on.At present,the research on joint structure design mainly focuses on the influence of joint size on joint strength.There are few studies on improving joint strength by increasing the number of contact surfaces.Therefore,a new type of self-inserting cemented joint structure is prepared by laying inclined template and Vacuum Assisted Resin Infusion process(VARI).The two parts are joined by secondary cementation.The structure has three contact surfaces and one of them is flat after joining.In this paper,three groups of variables are designed: lap length(30 mm,40 mm,50 mm,60 mm),inflection point number(0,1,2)and lap surface number(1,3).The experimental results show that:(1)the bearing capacity of the joint increases with the lap length.(2)Whether there is an inflection point or not has little effect on the bearing capacity of the joint,but when the inflection point structure is damaged,the deformation increases obviously.The ultimate bearing capacity of three-lap structure is approximately 1.73 times of that of single-lap structure.In this paper,Abaqus finite element software is used to simulate the interlaminar failure of composites by adding a cohesive element between adjacent continuum elements,two-dimensional Hashin criterion is used to simulate the fiber layer failure,and traction-separation criterion is used to simulate the adhesive layer failure.The simulation results show that the error between the experimental and simulated values can be controlled within 10% for three-lap structures with different lap lengths,which proves that the proposed structure can effectively simulate three-lap structures.