Study On Viscoelastic Damper Parameters In Concrete Frame Structures

Energy dissipation technology mainly weakens the seismic response by installing energy dissipation facilities in buildings,and improves the safety factor of building structures.Among them,viscoelastic dampers can not only provide stiffness but also add damping to the structure.They have better control effect on earthquake and wind vibration.In addition,they have many advantages,such as stable performance and low cost.Therefore,they are widely used in shock absorption structure engineering.The optimization of damper parameters and the location parameters of dampers in structures are still of great value for engineering application and research.Therefore,in this paper,the parameters of damper are studied as follows,and the relevant results are obtained:(1)On the premise of not considering the stiffness effect of the connecting member,according to the dynamic characteristics of the viscoelastic damper system under steady vibration and the calculation method of the damping ratio in the code for seismic design of building structures,taking the additional damping ratio of the viscoelastic damper as the control function,the loss coefficient of the viscoelastic damper is in the range of 0?2,and it is worth drawing a conclusion that the additional damping ratio of the structure increases with the loss of the damper.When the loss coefficient is constant,the additional damping ratio increases with the increase of the storage stiffness of the damper,and the relationship between the additional damping ratio and the utilization ratio of inter-layer displacement of the damper is quadratic.(2)Under harmonic load,the relationship between storage stiffness and loss stiffness of the additional system and the stiffness of the connecting member is obtained.When the damper loss coefficient is between 0 and 1,the storage stiffness of the additional system increases nonlinearly with the increase of the stiffness of the connecting member,and finally approaches the storage stiffness of the damper.When the damper loss coefficient is within 1 to 2,the storage stiffness of the additional system increases nonlinearly first,then decreases nonlinearly,and finally approaches the storage stiffness of the damper.The storage stiffness of the additional system reaches its maximum value when the ratio of stiffness of the connecting member to that of the damper is close to 5.The loss coefficient of the damper ranges from 0 to 2,and the loss stiffness of the additional system increases nonlinearly with the increase of the stiffness of the connecting member,and tends to the loss stiffness of the viscoelastic damper.(3)The control function of additional damping ratio is adjusted considering the influence of stiffness of connecting members.The parameter table of viscoelastic damper corresponding to the target damping ratio is given,which provides reference value for engineering application.(4)The effects of shear deformation between stories,axial tension and compression deformation of frame columns,angular displacement of beam-column joints,deformation of connecting walls and damping force on the displacement of dampers are analyzed by using wall-connected members.(5)In engineering applications,the multi-particle system is equivalent to a single-particle system.When the control function has an additional damping ratio of 0.02,the additional stiffness and loss coefficients of viscoelastic dampers can be determined by table 3.4.According to the principle of distribution,the demand stiffness of each floor is calculated and the parameters of each floor damper are determined.Based on this optimization method,the elastic time history analysis of 5-storey concrete frame structures under frequent earthquakes is carried out.The results show that the additional damping ratio in X direction is 0.021,and the additional damping ratio in Y direction is 0.020,which meets the initial expected value of 0.02.The feasibility of this design method is verified.At the same time,the elastic-plastic time history analysis under rare earthquakes is carried out.The results show that the viscoelastic damper improves the inter-story displacement angle of the structure and reduces the seismic response.It has reference value for practical application of engineering.