A Study On Dynamic Interaction And Semi-active Control Of Vehicle-bridge System

With the increase of the traverse speed of the train, the control measurement and method for the reduction of the dynamic response of high-speed train and bridge are one of the most important research directions. There are four sorts of control methods for the bridge structures, which are active control, passive control, semi-active control and composite control. With the fast development of smart materials recently, the application of magneto -rheological fluid (MR) damper is considerably concerned by many researchers. MR damper is excellent semi-active control device, with many merits such as simple structure, fast response, large dynamic range, and durability. Even in the case of failure of the control system, MR damper can be a passive control device. The control effect of MR damper is quite close to active control because of its reliability and adaptability.In this thesis, the effects of MR damper which is applied on bridge to reduce the vertical vibration after the coupling vibration of vehicle and bridge is investigated. The effects of the MR damper were studied on vibration through a few examples. The major work of this paper was done as following:Firstly, the vehicle–bridge equation which was solved using FORTRAN program was established base on the dynamic finite element method. And the dynamic response of the GUIZHOU SHUIDAO bridge with the traverse of vehicles was analyzed.Secondly, the working principle and the classical mechanics models of MR damper were elaborated. An adopted amended phenomenon model was selected to simulate the MR models used in this paper.Then, the MR damper was installed on 32 m simple supported bridge and 40 m simply supported bridge, the damping force of the MR damper was equal to an applied load. The anchor fix the MR damper was equal vertical stiffness added into the vehicle–bridge interaction system. So, the effect of MR damper controlling the dynamic response of vehicle–bridge interaction system was explained in two ways: (1) without regarding to vertical stiffness, only apply the damping force under the response of displacement, velocity and acceleration of the bridge; (2) regarding to both the vertical stiffness and the damping force under the response of displacement, velocity and acceleration of the bridge. The practicability and effectiveness of the MR damper controlling the response of the bridge was achieved.Finally three MR dampers were installed on the GUIZHOU SHUIDAO bridge and the controlling effect of the vehicle–bridge interaction system was calculated under different speeds of the vehicles.