| Energy-dissipating brace which webs have holes can effectively avoid the instability failure of traditional center brace and it has good hysteretic behavior.Through finite element software analysis,it can be seen that the stress distribution of the energy-dissipating plates with holes is large at two sides under the load.In order to make full use of web material to make even distribution of stress,the opening shape of energy-dissipating plate can be optimized.This paper analyzes the hysteretic performance of brace with different types of opening shape through the combination of experiment and finite element software,and proposes a reasonable form of opening.The main contents are as follows:（1）Low-cycle reciprocating loading was performed on the two specimens which webs opened diamond holes and elliptical holes.Two specimens are compared with the specimen which webs opened slotted holes,in order to analyse the different of failure modes,hysteresis properties,bearing capacity,rigidity degradation and energy dissipation capacity.The test results show that the energy dissipation brace through the perforated web yields to dissipate energy,and the failure of the two specimens occurs in the middle of the energy dissipation parts.The I-beam which to transfer force remain flexible throughout the loading process.The hysteretic curves of the three types of braces are full and the energy dissipation properties are excellent.Under the cyclic loading of the same level,the strength does not decrease basically.The diamond holes specimen has high bearing capacity,high stiffness,but weak deformation capacity.The bearing capacity of the elliptical holes specimen is similar to that of the circular holes specimen,the energy dissipation capacity of the elliptical holes specimen is slightly better,while the deformation capacity of the circular holes specimen is stronger.（2）The finite element model of energy-dissipating braces consistent with the test results was established by using ABAQUS finite element software,and a kind of opening hole which can utilize the full section to disspate energy by yielding is proposed.The parameters of energy-dissipating braces with long hole,diamond hole,ellipse hole and improved hole were analyzed,and the reasonable opening parameters and the influencing factors of energy dissipation capacity of each type of energy-dissipating brace were studied.The results show that the improved energy-dissipating webs can be used as a reasonable form of opening for energy-dissipating webs with uniform stress distribution,fuller hysteretic curve and higher bearing capacity.The bearing capacity and stiffness of the brace depend on the number of short energy-dissipating columns and the thickness of the web.The longer the holes length is,the better the energy-dissipating capacity of the specimen is.（3）Based on the web thickness,web length,short column width and short column length of energy dissipation braces,the calculation formulas of initial stiffness,yield and ultimate bearing capacity of four kinds of braces are proposed,which have little error with the finite element model data and can be used as reference for practical engineering. |
