Theoretical Analysis And Experimental Study On New Joint Of Single-layer Composite Aluminum Alloy Honeycomb Panel Latticed Shell

As the aluminum alloy structure with light weight,corrosion resistance and easy processing and many other advantages,especially the large span of single-layer aluminum alloy reticulated shell structure,because of its lightweight high strength and maintenance-free advantages,much architects and structural engineers Favored,is widely used in a variety of spatial structure areas.And the joints are the most important connecting parts in the single-layer reticulated shell structure.In view of the fact that the existing conventional aluminum alloy plate joints are not provided with the shear connection device in the joint area,the discontinuous range of the web joints of the aluminum alloy beams is caused,so that the joints are limited by the connected upper and lower ferrules Force,and thus can not be used to require a higher capacity of the long-span reticulated shell structure.In this paper,a wedge column shearing device is designed for the first time in the center of the joint,and a new type of high bearing capacity is provided.In order to explore the force characteristics,bearing capacity and failure mechanism of the new joints,this paper has carried out comparative experiments on the new joints and the existing traditional plate joints.The results show that the new joints have higher bearing capacity compared with the traditional plate joints ability,especially the ability to significantly improve the shear,the body stiffness also has a greater increase.The main contents and conclusions are as follows:(1)The design and processing of six aluminum alloy joints,through the new joint with the shear connection device and the existing traditional plate joint comparison test,found that the new joint significantly improved the traditional joint shear capacity and out-of-plane bending capacity,Performance on average more than 50%.(2)Three groups of different types of aluminum alloy joint test study show that the traditional plate joint failure mode is:the lower cover of the block pull shear or aluminum alloy beam yield;new joint failure mode is mainly for the connection of aluminum Beam torsion buckling damage,only when the thickness of the joint plate is small,will occur under the cover of the block pull shear.The load-displacement curve of the specimen shows that the thickness of the cover of the new joint has little effect on its bearing capacity,and the bearing capacity of the new joint is greatly improved compared with the plate joint.As the center of the new joint sets the wedge-shaped shear device,the bending deformation of the aluminum alloy beam changes to the reverse.(3)The theoretical capacity of the new joint(JD1)is significantly higher than that of the traditional board joint(JD2)of about 42.8%.The failure modes of the new joints obtained by the finite element simulation analysis are basically consistent with the experimental phenomena observed in the second chapter.From the comparison of the load displacement curves of the new joints(JD1,JD3,JD5),the theoretical curves given by the Elasto-plastic finite element analysis are in good agreement with the measured curves of the nodal tests,and the average error of the bearing capacity is about 8.3%.The new type of joint in the increase of the shear device and improve the state of the bolt on the cover plate,the cover plate in the bolt stress is greater than the lower cover,but because the strength of stainless steel bolts is much higher than the aluminum alloy cover,so no bolt Cut the cut.There is a large stress in the vicinity of the bolt hole of the cover plate and the aluminum alloy beam due to the stress concentration,and the rest is in the elastic state except for the compression buckling of the flange on the new joint.(4)Through the parameter analysis of the thickness and diameter of the new type of connecting plate,the optimization study is carried out under the premise of satisfying the bearing capacity of the joint.The results show that although the bearing capacity of the joint increases with the increase of the thickness of the connecting plate,the increase is more than that after the thickness of the web.(5)Based on the analysis of the existing traditional plate joint theory,the simplified formula of the ultimate bearing capacity based on the working mechanism of the new joint is given,and the experimental results of this paper and the related literature are compared and the application of the theoretical formula is pointed out.Scope and proposed amendments.