Research On Seismic Performance Of Energy Dissipation Brace With Openings In Fabricated H-section Steel Webs

The center-supported steel frame structure has high lateral anti-side efficiency and is widely used,but it also has the disadvantage of premature failure and exit work when it is significantly lower than the design value of bearing capacity under earthquake action.In order to avoid the buckling of the central support oblique rod and improve the energy dissipation capacity of the support,it is possible to consider installing metal dampers at both ends of the central support oblique rod to form an energy dissipation support.Based on this,a fabricated H-shaped steel web opening energy dissipation support is proposed..This kind of energy-consuming support is composed of web holed H-shaped steel and force-transmitting channel steel connected by bolts,which can effectively avoid the instability of traditional support diagonal rods under the action of earthquakes.It has simple processing,convenient replacement of energy-consuming panels,and energy-consuming performance.Superior and other advantages.（1）The prefabricated H-beam webs open hole energy dissipation support specimens with long round hole,elliptical hole and diamond hole were designed and manufactured,and the low-cycle reciprocating cyclic loading test was carried out to verify the feasibility of energy dissipation support and superior hysteretic performance.The results show that the hysteresis curve of prefabricated H-beam webs is full,the energy dissipation capacity is strong,and the deformation capacity is good.Under the action of axial load,the specimen mainly relies on the plate between the holes of the open web to enter the plastic energy dissipation.The end of the plate between the holes of the long round hole and the elliptical hole is the weak part,and the middle part of the plate between the holes of the diamond hole is the weak part.During the loading process,these parts enter the plastic part first and fracture occurs first.The bolt and channel steel are always in elastic state during loading.The specimens with long round holes,elliptical holes and diamond-shaped holes in the webs fail when the interlaminar displacement Angle reaches 1.5%,2.0%and 2.0%,respectively.During the test,only the energy dissipation plates with openings at both ends of the specimen were replaced,the channel steel was always in elastic state,and the bolt rod did not shear.（2）ABAQUS was used to establish the finite element model of the energy dissipation support of the fabricated H-section steel web with long circular holes,elliptical holes,and diamond-shaped holes to simulate the boundary conditions during the test,and the test loading system and material properties were used to test the material properties.Meta simulation.The simulation failure criterion is defined as follows:most of the area of the plate between the holes of the open web reaches the limit stress state,the plate between the holes has a large irreversible deformation,or the bolt rod enters the plastic deformation energy consumption stage and deforms.The curves obtained from the simulation are basically consistent with the test results.At the same time,the ABAQUS finite element modeling method and the finite element model are established reasonably and reliably,which meets the requirements of finite element parameter analysis,and can be used for subsequent energy dissipation support for fabricated H-section steel webs.Finite element analysis.（3）Using ABAQUS finite element software,perform finite element simulation for H-shaped steel webs with different opening shapes,analyze the influence of opening shapes on the energy dissipation capacity and deformation capacity of this type of energy dissipation support,and explore the rationality of bolts Layout method.Studies have shown that changing the web width has the greatest impact on the load-bearing capacity and initial stiffness of the energy dissipation support with long circular holes in the web,and the smallest impact on the specimens with elliptical holes in the web;changing the width of the plate between the holes has the effect on the energy dissipation of the diamond-shaped web holes Support has little effect.Changing the web thickness has a similar effect on the bearing capacity of the three types of web openings and the initial stiffness.When the main body of the test piece loses stability prematurely,it can be avoided by increasing the aspect ratio,reducing the thickness of the web,or choosing channel steel with larger flanges.It is recommended that the design range of the aspect ratio is between 4～7,and the aspect ratio is between 7～11.（4）Perform fine-parameter finite element simulation research on the energy dissipation support of the fabricated H-section steel web with long round holes in the web,explore the bolt arrangement,and derive the ultimate bearing capacity formula.When the web length is the same,the larger the width,the smaller the bearing capacity and initial stiffness,and the better the deformation ability.Changing the arc radius of the oblong hole has little effect on the hysteresis performance of the support.The longer the web length,the greater the supporting capacity and stiffness.In order to ensure a safe bolt working environment,while meeting the aspect ratio of the plate between the holes,it is recommended that the arc center distance of the hole end of the hole web is not less than 3.5d₀.When arranging bolts,arrange a bolt in the middle of the plate between every 3 pairs of holes.The longer the connection length of the test piece,the more unfavorable the bolt work.The specimens with elliptical holes on the web and the specimens with diamond-shaped holes on the web have little effect on the connection parts and bolt holes.For the bolt arrangement,please refer to the energy dissipation support of the web with long round holes.The ultimate bearing capacity formulas obtained are more consistent and can provide references for actual projects.