VIBRATION CONTROL OF A SIMPLY SUPPORTED BEAM USING VISCOUS FLUID DAMPER

Abstract

This thesis studies the application of a viscous fluid damper (VFD) for the reduction of vibration in a simply supported railway bridge subjected to high speed trains. To reduce the multi resonance peaks, a number of viscous fluid dampers are used. Therefore, the bridge is connected with a set of VFDs with bridge slab and an auxiliary structure placed beneath the main bridge deck and resting on the abutments. The study proposed here that the resonance generated on the beam can be drastically suppressed by this type of device. First of all the main beam connected to the damping system associated with sinusoidal excitation, and it is analyzed to discover the damping system which lowers the overall response at resonance. And it is based on reduction of mitigating flexural vibration therefore the bridge and auxiliary structure both are considered as simply supported beam having Bernoulli-Euler behavior whereas partial differential equations have been used to model the characteristics of damping material. First a parametric study for the planar model occurred which led to a dimensioning process of the dissipating system. Various design constraints have been used such as tuning ratio, damping ratio and the mass ratio, on the reduction of vibration performance for the damping parameters. For the technical feasibility of this retrofit design, a mathematical model of a high speed railway bridge with unacceptable vertical accelerations is taken. Numerical outcomes demonstrate that the dynamic response of beam structure can be reduced in a significant manner at resonance by using this proposed damping system. The strategy used to reduce vibration here is simple and robust and applicable when multiple resonance is a major problem.