A POWER FLOW METHOD AND ITS MODELING FOR COUPLING VIBRATION ANALYSIS OF TRAIN-TRACK-BRIDGE SYSTEM IN THE MEDIUM-TO-HIGH FREQUENCY RANGE

It is very crucial to obtain the vibration of a bridge and the power input to it through wheel/rail interactions in order to predict structure-borne noise from the bridge. The time domain train-track-bridge interaction analysis is widely used to solve the low frequency vibration problem of the coupled system. However, its efficiency becomes quite low in the medium-to-high frequency range. This paper then aims to propose a power flow method to tackle the system based on the principle of the force method in a frequency domain. The rail component in the system can be represented by either an infinite Euler beam or a Timoshenko beam. The bridge component can be modeled by an infinite Kirchhoff plate, a Mindlin plate or a finite element model. And the fasteners between the rail and the bridge are considered as a spring-dashpot pairs. The compatibility equation of the coupled system is obtained by regarding the internal forces of the spring-dashpot pairs as unknowns. In the case study, the vibration power of a U-shaped girder and a box girder is calculated with various models for the rail and the bridge components. The results show that the shear effect of the bridge deck significantly influences the power input to the U-shaped girder. The use of a conventional Kirchhoff plate model can lead to a calculation error of 15 dB, while the adoption of a Mindlin plate model can gain both high accuracy and efficiency. A Mindlin plate model still produces large computation errors compared with the finite element model of a box girder using volume elements.