Study On Factors Affecting Seismic Performance Of Double Beam Rigid Connection Joints In Box Joint Domain

In order to solve the problem of weak seismic performance of traditional H-shaped steel beam column rigid connection nodes,this article improves the double beam rigid connection nodes and proposes a box node domain double beam rigid connection node.The seismic performance and mechanical performance of three different node domain construction forms of double beam rigid connection nodes are compared using finite element software ABAQUS.By analyzing the failure mode and equivalent plastic strain of the double beam rigid connection nodes The parameters such as hysteresis curve,skeleton curve,stiffness degradation,and energy dissipation capacity demonstrate that the box node domain double beam rigid connection node proposed in this paper has excellent seismic performance.On the basis of this research,variable parameter simulation analysis was conducted using finite element software ABAQUS to study the effects of factors such as connection plate thickness,beam section size,beam span to height ratio,beam flange width to thickness ratio,and stiffener thickness on the seismic performance of nodes.The main conclusions ultimately drawn are as follows:(1)Compared to other forms of double beam rigid connection nodes,box node domain double beam rigid connection nodes have strong stiffness and strength.Under repeated loads,they generate less plastic deformation,have greater bearing capacity,and have stronger seismic performance and it has stronger applicability in practical engineering.(2)The thickness of the connecting plate on the beam web has a small impact on the failure mode,seismic performance,and energy dissipation capacity of the node.When the connecting plate thickness is relatively thin,it can not only enhance the mechanical properties of the node to a certain extent,but also reduce the amount of steel used.Therefore,it is recommended that the thickness of the connecting plate be slightly thicker than the beam web,and the optimal value is 10-12 mm.(3)The cross-sectional size of the beam has a significant impact on the load-bearing capacity and seismic performance of the node.It is recommended that when designing rigid connection nodes with double beams in the box node domain,the best effect is to use double beams assembled from beams with the same cross-sectional size.When using beams with different cross-sectional sizes to form double beams,it is recommended that the cross-sectional size of the double beams should not be too large,and the beams with smaller cross-sectional sizes should be close to the load-bearing side,Beams with larger cross-sectional dimensions should be kept away from the side under stress,in order to maximize the performance of the beam.(4)The span to height ratio of beams has a significant impact on the performance of double beam rigid connection nodes in the box node domain.When the span to height ratio of the beam is large,the mechanical indicators such as bearing capacity and ductility of the node decrease.When the span to height ratio of the beam is small,although the performance of the node is improved to a certain extent,a smaller span to height ratio can easily lead to stress concentration at the end of the beam,making the weld seam prone to damage,leading to overall failure of the specimen.Therefore,it is recommended to take a beam span to height ratio of around 9.0 when designing box node domain double beam rigid connection nodes.(5)The width to thickness ratio of the beam flange has a significant impact on the failure mode and seismic performance of the double beam rigid connection node in the box node domain.As the aspect ratio gradually decreases,the failure mode changes from buckling deformation of the beam flange to buckling deformation of the beam web.On the other hand,when the width to thickness ratio of the beam is small,compared to the specimens with larger width to thickness ratio,although the performance of the specimens has been improved to a certain extent,a large amount of plastic strain has accumulated at the weld seam,and no obvious plastic hinge has been generated at the upper and lower flanges of the beam.Therefore,it is recommended that when designing box node domain double beam rigid connection nodes,the width to thickness ratio of the beam flange should not be less than 6.0.(6)The thickness of the stiffener has little effect on the failure mode of the node,but it has a significant impact on the seismic performance and other performance of the node.When the thickness of the stiffener is large,the stiffness,bearing capacity,and plastic deformation of the node are improved to a certain extent.However,as the thickness of the stiffener increases to a certain extent,the impact on the performance of the node gradually decreases.At the same time,excessive thickness of the stiffener can easily cause local instability and damage.Therefore,in summary,it is recommended to design rigid connection nodes in the box node domain,with the thickness of the stiffener compared to the thickness of the beam flange,A thickness of 2-4mm is sufficient.