Experimental Investigation Of Buffeting Force On A Train In The Truss-Girder Bridge

With the development of high-speed railway in our country, the train speed is faster and faster, at the same time, the railway bridge span is more and more larger. The dynamic function of vehicle-bridge system will become more and more obvious, when under the action of natural wind. In order to strengthen the safety of the train when passing through the bridge, it is necessary to study vehicle-bridge system refinemently. Buffeting is a limited vibration caused by the pulsating component of nature wind, when the train passing through the bridge, it will cause vibration which make people uncomfortable. So it is necessary to have a study on the key parameters of buffeting force of Vehicle-bridge system. This article adopts theoretical analysis and wind tunnel test method, with a large span railway truss bridge as the background, study on the three component coefficient, correlation and aerodynamic admittance of Vehicle-bridge system under the turbulent wind. The main contents:1) Introduce the bridge vibration phenomenon caused by wind. Reviews the research status quo of the aerodynamic admittance and train aerodynamic research.2) The turbulent characteristics of atmospheric boundary layer are described. Two turbulent wind fields have been stimulated in wind tunnel, and then characteristies of turbulence is analyzed.3) Ilustrate the flow around the train, Analysis the steady and unsteady aerodynamic force on the vehicle-bridge system caused by the nature wind. make a load test on the vehicle-bridge system in wind tunnel and get the three component coefficient.4) Pressure method is used to measure the fluctuating pressure on the surface of the train section, get the characteristics of average pressure and the fluctuating pressure distribution around the train section, calculate the aerodynamic force on the train .study the correlation of aerodynamic force across the train and fit out the coherence function.5) Identify the aerodynamic admittance of the train by the method of equivalent aerodynamic derivatives and fit out the aerodynamic admittance function with empirical formula.