| In the practical engineering application,the mild steel damper with coupling beam usually only considers the effect of shear,but the actual coupling beam is in the complex state of axial,bending,shear and other loads combination.Based on two engineering cases in a city,this paper studies the internal force law of coupling beam,and uses Abaqus finite element software to analyze the performance of coupling beam mild steel damper under complex stress state.The main contents and conclusions of the study are as follows:(1)At present,constitutive relations of metal materials are mostly described by strengthening criteria.For the strengthening of the steel yield after model are mainly to the improved model and follow-up improved model,the former mainly represent the change of the size of the yield surface,which yield surface position of translation,and for most of the structural steel in yield showed is that contains both the follow-up after reinforcement and to strengthening the mixture of strengthening characteristics,etc.In this paper,the finite element model of the coupling beam mild steel damper is established by using the hybrid reinforcement model which conforms to the postyield behavior of steel,and the accuracy of numerical simulation is further improved.(2)A simplified calculation model of the internal force of the connecting beam is proposed.Based on the simplified calculation model,the estimation formulas of the axial force,shear force and bending moment of the connecting beam are deduced,and the estimation formulas of the ratio of the axial force and shear force of the connecting beam and the ratio of the bending moment and shear force of the connecting beam are deduced.Based on two engineering cases in a city,and using the architectural structure design software of Yingjianke,the axial force,shear force and bending moment data of the two engineering cases under the action of earthquake are extracted respectively,and the internal force law of the connecting beam is studied.The results show that when the earthquake action increases,the axial force,shear force and bending moment of the connection beam will also increase with the increase of the earthquake action,and there is a certain relationship between the three,from the data extracted from two engineering cases: the ratio of the axial force and shear force of the connection beam is between 0.5～2.5,and the ratio of the numerical moment of the connection beam and shear force is between 0.45～0.8.The calculation results of axial force shear ratio estimation formula and bending moment shear ratio estimation formula are within 20% of the calculation results of Yingjianke model.(3)Using the finite element analysis software Abaqus,the finite element model of the soft steel damper with continuous beam was established to analyze the effects of axial action,bending action and combination of axial and bending action on the mechanical properties of the soft steel damper with continuous beam.The results show that the axial force has a great influence on the mechanical properties of the soft steel damper.With the increase of the axial force,all the properties of the damper will decrease.The bending moment has a great influence on the mechanical properties of the soft steel damper,which not only seriously reduces the mechanical properties of the damper,but also makes the positive and negative mechanical properties of the damper inconsistent.The axial displacement will affect the mechanical properties of the damper at the initial stage of loading,but the effect will gradually disappear with the loading,and the hysteretic energy dissipation capacity of the damper is little affected.The bending Angle,tension bending displacement and compression bending displacement affect the mechanical properties of the damper at the early stage of loading,and make the positive and negative mechanical properties of the damper inconsistent,but have little effect on the overall energy dissipation capacity of the damper. |
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