Research On Static Performance Of Plate Joints Of Aluminum Alloy Reticulated Shell Structure Connected By Stainless Steel Bolts

The construction industry focuses on vigorously developing prefabricated buildings.With the need of hosting large-scale conferences and competitions in China,its application in public buildings is also gradually increasing.Aluminum alloy is widely used in exhibition halls,stadiums,botanical gardens,pedestrian bridges and other building fields due to its light weight,high strength,good corrosion resistance,high recycling efficiency and good self-assembly effect.As a common node of aluminum alloy structure,the plate node is inconvenient to install and adjust when using ring groove rivets to connect,and it is not easy to disassemble and replace.The convenient performance of stainless steel bolts is prominent,but there are few studies on the performance of related joints,and the application is limited.As a sub-item of the two topics "Optimization of Aluminum Alloy Structure" and "Research on Key Technologies of Aluminum Alloy Reticulated Shell Construction",this paper conducts relevant basic research on the static performance of plate joints in aluminum alloy reticulated shells connected by stainless steel bolts.The content is as follows:1.The 6061-T6 aluminum profiles,aluminum plates,Q345-B steel plates,and A2-70 stainless steel bolts used in the theoretical analysis and tests were selected to carry out mechanical property tests to provide the constitutive relationship of the materials for subsequent research.2.Through the finite element analysis of shear specimens,the influences of friction coefficient and stainless steel bolt pretension on slippage and ultimate bearing capacity were studied.Recommended values for pretension under stainless steel bolted connections were determined.Combined with the actual project,a method for calculating the deflection change of the reticulated shell through the deformation of the aluminum alloy plate joint is proposed.3.Through the tests of 12 shear specimens,the friction coefficients of aluminum-aluminum shear specimens and steel-aluminum shear specimens were measured,which provided the basis for the stiffness analysis of plate joints.The deformation,ultimate bearing capacity and failure form of the shear specimens with pretension p=0kN and p=43kN were compared with the calculation results of the finite element model,so as to check the finite element model of the shear specimens.4.Through the experimental study of the "in-line" aluminum alloy plate joint,the corresponding mid-span bending moment and the corresponding rotation angle are calculated by using the measured strain and displacement of the bar section.Then,the rotational stiffness of the aluminum alloy plate joint relative to the strong axis of the member is obtained.5.In the finite element model of the "in-line" aluminum alloy plate joint,the pretension of stainless steel bolts and the aluminum-aluminum friction coefficient are consistent with the test support conditions.The transitional stiffness and the rotational stiffness of the strong axis and the weak axis of the aluminum alloy plate joint are obtained through analysis,and the transmission path of the shear force of the plate joint is analyzed.6.The aluminum alloy plate joint is improved,and its stiffness change after adding strengthening structural measures is analyzed.The main influencing factors of stiffness are quantitatively analyzed.The pretension of A2-70 stainless steel bolts was 43 kN(the torque was 55N·m),and the friction coefficients of aluminum-aluminum and steel-aluminum were respectively 0.138 and 0.093,which have been used to provide technical parameters for the aluminum alloy in Shanxi Provence.