Study On The Flexural Performance Of Channel Steel Beam To Square Tubular Column Modular Plug-in Connection

At present,the country has put forward higher requirements for building industrialization,and the existing prefabricated buildings have been unable to meet the requirements.Modular buildings can adapt to the development speed of The Times,which is a construction method worthy of advocating for building industrialization.The connection between modules is the key part of the modular building,which has a significant influence on the overall mechanical performance of the structure.Such drawbacks in the existing inter-module connections hinder the development of modular architecture like a lack of sufficient construction space,the effect of on-site welding on the construction efficiency and the low efficiency of the inability of collaborative work of the assembly connections.For this reason,this paper develops a new type of modular plug-in connection,studies the failure mode and flexural performance of the new connection through full-scale static test and numerical simulation,analyzes the influence of different parameters on the flexural performance of the modular connection under vertical plane load,and summarizes the flexural mechanism.On this basis,the mathematical model of the flexural moment-rotation relationship of the connection is presented,which can provide reference for the new modular plug-in node in engineering application.Three new modular connections with different parameters were tested for in-plane flexural performance,to study the failure modes,moment-rotation relationship,flexural design bearing capacity,ultimate bearing capacity,initial stiffness,stress-strain relationship in the key connection areas of the new modular connection and to compare the influence of different composite beam stiffness ratios and the existence of axillary plates on the flexural performance of the connections.The results show that the failure mode of the new type of modular connection without axillary plate is the weld crack of the connection in the module,and the failure mode of the connection with axillary plate is the local buckling of the compression flange of the composite beam.The reduction of the stiffness ratio of composite beam and the increase of the axillary plate in the connection domain have greatly improved the initial stiffness,flexural design bearing capacity and ultimate bearing capacity of the new connection.ABAQUS finite element software was adopted to establish the three different connection models,which were identical with the test specimen.The failure mode and flexural performance of the finite element model and the test specimen werecompared and verified,and according to the mises stress distribution of the connection,analyzed the stress distribution of various components,the results show that the failure mode and the flexural moment-rotation relation of the finite element model are in good agreement with the test results,and the reliability of the finite element model is verified.ABAQUS was used to establish 41 finite element models for parameter analysis,considering the influence of factors such as the stiffness ratio of composite beam,the thickness ratio between beam end plate and column wall,the thickness ratio between plug-in and column wall,the length of plug-in and the gap between plug-in and column wall on the flexural performance of new modular plug-in connections.The analysis shows that the stiffness ratio of composite beams affects the flexural performance of connections and the relative stiffness of beams and columns.The thickness of column wall is the key factor that affects the flexural performance of modular connections and determines the failure mode of modular connections.The influence of different thickness ratio of beam-end plate to column wall,different thickness ratio of plug-in to column wall on failure mode,stress distribution and flexural performance of modular connections is affected by column wall thickness.When the thickness of the column wall is 6-8mm,the influence of different thickness ratio is obvious.The length of the plug-in has no obvious effect on the flexural performance of the connection.The gap between the plug-in and the column wall has a significant effect on the initial stiffness of the connection.Based on the results of experiment and finite element analysis,the mechanism analysis of the flexural failure mode and important factors of the new type of connections were carried out.The failure modes are mainly divided into three types:weld cracking,column wall buckling and beam flange compression buckling;the increase of the ceiling beam height increases the bearing capacity of the beam section;the thickness of the column wall and the thickness relationship of the end plate-column-inner plug determine the stiffness and mechanical properties of the column;the gap between the plug-in and the column wall affects the coordinated force of all components.A mathematical model of the moment-angle relationship of the connections is proposed,and its parameters are influenced by the stiffness ratio of the composite beam,the section stiffness of the end plate-column-plug in.The model results are compared with the finite element results,the error is within 20%,and the reliability is high.The paper has 67 drawings,23 tables,93 references.