The Study On Seismic Performance Of A New Type Of Self-Resilient Lead Viscoelastic Damper And The Steel Frame Structure

The self-resetting lead-viscoelastic damper is a new type of energy-consuming damper device.The device can not only dissipate most of the energy,but also reset the structure to the initial position or elastic deformation range after the earthquake.It can effectively reduce the structural displacement to avoiding components damage.However,most of the dampers have the disadvantages of complicated structure,high installation cost,and short replaceable time period,which make it difficult to apply for practical engineering.In this paper,an new lead-viscoelastic damper was proposed.The structure and working mechanism of the damper were introduced.The finite element model was established by ABAQUS.The variable-parameter analysis of the self-resetting damper was carried out,and the damper consumption was studied.The performance and reset performance were finally analyzed by response spectrum analysis and dynamic time history analysis of the six-layer steel frame structure with the damper.The main research contents and conclusions of this paper are as follows:(1)The state of the art of dampers at home and abroad was briefly summarized,and the shortcomings of current research were analyzed.A new self-resetting lead viscoelastic damper is proposed.The core part of the new damper includes composite viscoelastic layer,upper and lower connecting end plates,sheared steel plate,constrained steel plate and lead core.The reset part of the new damper uses the lead core in the deformation process.The dynamic recovery and recrystallization properties make the damper to achieve self-resetting characteristics.The energy consuming part of the new damper includes the shearing and squeezing energy of the constrained steel plate and the shear steel plate,and the shear hysteresis energy of the rubber material.The working principle of the new damper was expounded,which was easy to construct and clear mechanism.(2)The finite element model of the self-resetting lead viscoelastic damper was established by the finite element software ABAQUS.The low cycle reciprocating loading was carried out.And then the simulated hysteresis curve of the damper was compared with that of the experiment.The results show that the two curves agree well.Under the same displacement,the energy consumption and mechanical performance of the damper are only within 10%,which verifies the rationality and reliability of the model.(3)The performance of the new self-resetting lead viscoelastic damper proposed was studied in this paper.Considering the lead diameter,the lead center distance,the shear modulus of rubber material,composite viscoelastic layer area,total thickness of composite viscoelastic laye,thickness ratio of single-layer steel sheet to single-layer rubber,the effect of these six parameters on the reset performance and energy dissipation performance of the self-resetting lead viscoelastic damper were analyzed.The results show that the lead diameter,the shear modulus of the rubber and the area of the composite viscoelastic layer have a great influence on the energy consuming capacity of the damper.The spacing of the core of the lead has little effect on the energy consuming capacity of the damper.The reasonable range of the total thickness of the layer is 22~30mm.The thickness ratio of the single-layer steel sheet to the single-layer rubber has a great influence on the damper,and the thickness ratio should be controlled between 0.34~0.69.(4)Under frequent earthquakes,the seismic performance of the steel frame structure embeded with the new self-resetting lead viscoelastic damper and the steel frame structure embeded with the common damper and the original steel frame structure were studied respectively.Interlayer displacement and interlayer displacement angle of the three structures were compared under the vibration mode decomposition response spectrum.The results show that the interlayer displacement and interlayer displacement angle of the steel frame structure with the new self-resetting lead viscoelastic damper are reduced by 12.4% and 5.4%,respectively,compared with the steel frame structure with the ordinary damper.(5)Under occurrence earthquake,the maximum displacement of the top layer and the maximum acceleration time history of the top layer of the steel frame structure of the conventional damper and the steel frame structure of the new damper were analyzed.The results show that under the rare occurrence earthquake,the maximum displacement and maximum acceleration of the top layer of the new damper steel frame structure are reduced by 12.6% and 33.1% on average.This indicates that the new self-resetting lead-viscoelastic damper can effectively dissipate seismic energy and effectively reduce the seismic response of the structure.The proportion of damping dissipation energy of the new damper steel frame structure and the ordinary damper steel frame structure under rare occurrence earthquakes was analyzed.The results show that the damping energy dissipation of the steel frame structure with the new damper is above 50% the total input energy.Therefore,under the rare occurrence earthquake,the controlled structure can effectively dissipate the seismic energy and reduce the damage caused by the earthquake.