Research On Shear Resistance Of Cold-formed Thin-walled Steel High-strength Bolt Connections

Cold-formed thin-walled steel has been widely used in industrial plants and civil buildings because of its advantages such as light weight and high strength.The common connection method of cold-formed thin-walled steel is ordinary bolt connection.Compared with ordinary bolts,highstrength bolts are subjected to a large pre-tension force before being subjected to external loads.A large amount of friction will be generated between the contact surfaces,which can prevent relative slippage between the contact surfaces.Can improve the overall working performance of the structure.At present,the high-strength bolt connection is mainly used for ordinary steel structures.If the high-strength bolt connection is applied to the engineering practice of cold-formed thinwalled steel reinforcement,the shear bearing capacity of the cold-formed thin-walled steel structure system will be improved to a certain extent.Based on this research background,this paper uses M8 high-strength bolts with strength class 12.9 to connect 2mm thin plates to make cold-formed thin-walled steel high-strength bolt connectors.Shear performance tests on connectors with different torque values and using ABAQUS The simulation of shear performance test was carried out.The test results are compared with the finite element simulation results and the shear bearing capacity of the cold-formed thinwalled steel high-strength bolt connection is analyzed.According to the specifications of this shear test specimen,the specific research content and results are as follows:(1)Analysis of the results of the shear performance test found that when the applied torque value is less than or equal to 5N·m,the shear connection has the same shear performance curve as the ordinary high-strength bolt connection thick plate,including the friction transmission stage,relative slip In the stage,the bolt bar and the bolt hole wall are subjected to pressure and force transmission stage,the failure stage is four stages,and the shear bearing capacity value of each stage is obtained.20N·m is the ultimate torque of the shear specimen of this test,and the larger torque value does not significantly improve the shear performance of the specimen.(2)The value of the ultimate shear bearing capacity of all test pieces fluctuates around 30 k N this time,indicating that the ultimate shear bearing capacity has little relationship with the applied torque value.(3)When the torque value is less than or equal to 5N·m,the torque coefficient of the 2mm thin plate of the 12.9 grade M8 high-strength bolt connection is 0.04,which is far less than the torque coefficient range of the conventional high-strength bolt connection.(4)The finite element analysis was carried out,the test results were compared with the finite element simulation results,and the shear load carrying capacity of the cold-formed thin-walled steel high-strength bolt connection and the calculation formula of the shear stiffness of the friction connection were further proposed under the application torque value less than 5N·m.