Research On Mechanical Characteristics Of Universal Accelerated Oscillator Mass Dampers

With the advancement of science and technology,the development of China'stransportation field is becoming more and more perfect.Bridges play an important role in the transportation road network and undertake the important mission of crossing mountains,valleys,rivers and lakes.On the premise of satisfying the basic mechanical properties,the bridge structure is increasingly developing towards the trend of large spans,softness,irregular shapes,and beautiful appearance.Cable-stayed bridges and suspension bridges,as two typical representatives of large-span bridges,have gradually become very popular bridge types in bridge engineering.In recent years,vibration control of long-span bridges has become an enduring research topic.Earthquake loads often last for a short period of time,and once they occur,they often cause huge damage to the bridge structure.In order to improve the seismic performance of large-span bridges,inspired by TMD and AOD dampers,this paper proposes a universal damping device-Universal Accelerated Oscillator Mass Damper(UAOD),which is a damping device suitable for controlling the vibration of bridge structures.This paper studies the UAOD system,analyzes its parameters and applies them to actual engineering cases.First,the component and working principle of the UAOD system are introduced.Through the Lagrange theory,the analytical expression of the motion equation of the UAOD system is derived.Combined with a simple calculation example,the analytical solution was verified using two methods: finite element software ANSYS and simulation program Simulink.With the help of transfer function,the analytical solution of the displacement amplification factor of the main structure is solved.In order to facilitate the subsequent research,the analytical solution is dimensionless.Next,the parameters in the dimensionless analytical solution are analyzed,and the relationship between the damping ratio,transmission ratio,mass ratio,frequency ratio and the damping effect is obtained.It is found that the greater the transmission ratio r and the mass ratio ?,the greater the effective range of the shock absorption frequency domain,but not that the larger the mass ratio ?,the peak of the seismic response is not reduced,and there is an optimal mass ratio ?0.Meanwhile,the relationship between the frequency ratios that the frequency ratios B = 2A and C = A,will take a bettershock absorption effect.An optimization method is used to optimize a calculation example,and the optimal frequency ratio B and the frequency ratio C and the corresponding optimal solutions,the optimal mass ratio ? and the mass ratio ? are obtained.In order to check the longitudinal vibration of UAOD,UAOD was applied to the three-span continuous girder bridge.A three-span continuous beam bridge model was established using ANSYS,and its eigenvalue analysis was carried out.Next,the three-span continuous girder bridge with TMD installed at position 1 # pier beam junction and 3 # pier beam junction was analyzed in Time history.Then the effect of UAOD on the abutment,main girder and pier at three locations was studied.By comparing and analyzing the results,it was found that installing UAOD at the location of the abutment can achieve a more ideal effect.Then compare the vibration control effect of UAOD,UAODopt and TMD on the bridge structure,and find that UAODopt has the best effect,which proves the correctness of the previous parameter analysis conclusion.In the transverse bridge direction,the analysis of the Zhangjiakou pedestrian suspension bridge shows that the use of the UAOD system can significantly reduce the peak seismic response of the bridge structure in the transverse bridge direction compared with the wind cable.At the same time,under the action of different seismic waves,UAOD can exert a stable shock absorption effect.Explain the effectiveness of UAOD system shock absorption.