Vibration Control Of Continuous Girder Bridge By Tuned Viscous Mass Damper Based On Complex Eigenvalue Analysis

Tuned Viscous Mass Damper(TVMD)is a new type of damping device,and its special mass amplification mechanism can achieve efficient damping of continuous girder bridges.In recent years,the research on the analysis of complex modal parameters of structures has been continuously deepened.Complex frequencies and complex modal vectors play an important role in analyzing the dynamic characteristics and vibration response of structures.In this section,the complex modal parameter analysis method is used to study the vibration reduction mechanism of the TVMD,the parameter optimization and response analysis of the continuous girder bridge are realized.The main contents are as follows:(1)First,install a TVMD with a single degree of freedom structure as the analysis model,and the optimal parameters of the damper are determined based on the traditional fixed point method.By analyzing the complex modal parameters of the system,the theoretical formulas of frequency ratio and damping ratio at the bifurcation point of the complex frequency are obtained,and then compared with the optimization results of the fixed point method,a method of data correction is proposed to realize the use of complex modal parameter analysis parameter optimization.(2)The simplified model of the three-span continuous girder bridge is used as the analysis model,and the complex modal parameter analysis method is used to tune and optimize each order mode of the structure.The variation law of the complex frequency locus curve under different inertial masses is analyzed and compared,and the approximate solutions of the corresponding parameters are proposed for the geometric characteristics of the bifurcation point of the complex frequency.At the same time,the influence of the main structure and the damper parameter changes on the vibration damping performance of TVMD is studied.The results show that within a certain range,TVMD maintains a efficiency vibration damping performance for each mode of the structure..(3)The multi-layer shear frame is used as the analysis model to study the optimization law of complex modal parameters under the action of single and multiple TVMD.By adjusting the installation position and number of dampers,the vibration control of the first-order and second-order modes of the structure is realized,which further proves the high efficiency of the low-order mode of TVMD tuning flexible structure.For multi-degree-of-freedom structures,the idea of using optimization functions to assist the optimization process is proposed.Taking the dimensionless peak value of the first layer displacement of the structure as the control target,the excellent vibration reduction effect of TVMD after the optimized parameters is verified.(4)On the basis of understanding the multi-degree-of-freedom structure tuning optimization law of the complex modal parameter analysis method,the optimal design of the continuous girder bridge fine model is realized.The system equations of the lateral and longitudinal bridge directions are established,and the complex modal analysis method is used comprehensively to obtain the optimized parameters of TVMD in two typical states.The effectiveness of TVMD in vibration control of continuous girder bridges was verified by analyzing the peak response of the structure at key locations.