Research On Design Method Of Diagonal Bracing Variable Damping Friction Damper System

This paper mainly studies the design method of additional damper system and the parameter optimization design method of variable damping friction damper system which can meet the design goal of seismic performance of energy dissipation structure.First,three steel frame structure models were designed,establish energy dissipation structure,time-history analysis of conventional structures and energy-dissipation structures under rare earthquakes by finite element analysis software Midas gen,the analysis results of interlayer displacement angle,interlayer velocity and interlayer acceleration are analyzed and compared as evaluation indexes,and the applicability of the design method of additional damper system is studied.A variable damping friction damper system(VRFD)designed with a parameter optimization design method through a variable damping friction damper system and an energy dissipation structure with a common type friction damper system(FD)installed in rare earthquakes and fortifications Time history analysis under earthquake,The structural interlayer displacement is used as an evaluation index to analyze and compare.The accuracy of the parameter optimization design method for variable damping friction damper system is studied.This paper mainly completed the following research.(1)An improved design method for structural parameters of displacement type and diagonal bracing friction damper system is proposed.Firstly,the design method of the additional friction damper system proposed by Professor Sakai of Japan to meet the seismic performance design of energy dissipation structure is introduced.The applicability of the design method of the damper system in China is studied.Three steel frame structures are designed.The energy dissipation structure is designed by the design method.The seismic performance of the conventional structure and the energy dissipation structure is analyzed and compared under the action of large earthquakes.The design of the design method and its improved design method are generally installed.The seismic performance difference between the energy absorbing structure of the friction damper and the conventional structure.The numerical analysis shows that the energy dissipation structure designed by the improved structural parameters design method of the friction damper system,the interlayer displacement angle is obviously reduced and the interlayer deformation distribution is uniform,and the structure can fully meet the seismic performance target.The main structural members have no plastic deformation,and the secondary structural members can only be slightly deformed at most,and can still be used after general maintenance,and the interlayer velocity and acceleration are also reduced to some extent.The analysis found that the reason is that the initial damping of the original method is lower than the value of the structure,and the effect of structural displacement reduction is not obvious.By trial calculation,when the structure is simplified to a single point system,the ductility coefficient is slightly reduced,and the elastic stiffness ratio of the additional system is appropriate.Improvement can make up for the influence of the design method on the applicability of the energy dissipation structure design in China.(2)A parameter optimization design method for variable damping friction damper system model is proposed.The variable damping friction damper system model has five important parameters,namely high and low order damping force,high and low order stiffness and low damping force side hole length.Using the control variable method,the low-order damping force of the variable damping friction damper system is changed between 0.1?1 times of the high-order damping force,and the low-order stiffness is changed between 1?10 times of the high-order stiffness.The seismic performance of the damper system structure at different parameters gives the best parameter design method.The data analysis shows that the low-order damping force of the variable damping friction damper is set to 0.5 times of the high-order damping force,the low-order stiffness is set to 3 times of the high-order stiffness,the structural equivalent damping ratio is the highest,and the displacement control effect is higher.After the variable damper system parameters are set according to the proposed design method,the VRFD system can achieve better damping effect than the FD system during the medium earthquake,the damper vibration efficiency is higher,the structural interlayer displacement is smaller,and the VRFD system will be The higher-order damping force of the structure is increased by 1.2 times,and the seismic performance under large earthquakes can be improved to be equivalent to the structure of the FD system.