Test Research On Hysteretic Behavior Of Dissipated Energy Braces With Openings In Rectangular Steel Tube Webs

When encountering moderate or major earthquake,the central brace often loses its bearing capacity,the main reason is that the members are compressed and lose their stability.In order to avoid this situation,combined with metal damper and central brace,this paper puts forward the rectangular steel tube web opening energy consumption brace,and metal damper is added at both ends of the brace.When the earthquake occurs,the plate between the holes will be sheared,the main square steel tube is in the elastic stage.In this paper,the hysteretic behavior of energy dissipation braces with openings in rectangular steel tube webs is studied through the main steps of "pre simulation-actual test-simulation verification-parameter analysis".The research contents are as follows:(1)In this paper,loading tests of energy dissipation braces with openings in rectangular steel tube webs are carried out to study the effects of different opening modes and opening sizes on the overall performance of the braces.The results show that the energy dissipation brace with openings in rectangular steel tube webs has abundant hysteretic curves and excellent energy dissipation performance,which mainly depends on the yield of plates with elliptical holes to dissipate energy and has good stability.There is no sudden decrease of strength and stiffness before the specimen loses the bearing capacity,which meets the requirement of no overall instability of the brace.(2)ABAQUS finite element software is used to simulate and verify,and the rationality is proved by comparison test.A total of 21 full-scale specimens with openings in rectangular steel tube webs from three series were designed,and the effects of the changes of the minor axis and major axis of the elliptical hole on the hysteretic behavior and bearing capacity of the braces were analyzed.(3)On the basis of finite element simulation,the hysteretic performance parameters of full-scale model were analyzed,The conclusions are as follows: among the three influencing parameters(long axis,short axis and thickness of perforated web),the height of the plate between the holes determined by the short axis has a greater impact on the mechanical properties of the specimen,and the specimen mainly relies on the plate between the holes to enter the plastic state to dissipate energy.Secondly,the deformation capacity of the specimens with double-sided single row openings is better than that of the specimens with four-sided single row openings,while the bearing capacity of the former is lower than that of the latter.During the whole loading process,the main square steel tube is always in the elastic stage,which conforms to the design idea of "weakening both ends is equal to strengthening the middle part".