The Temperature Deformation Of Single Span Maglev Track Girder And Influence On The Vibration

As a key component of the maglev system, the maglev guideway is one of the main controlling factors of the traffic safety and comfort. In this thesis the deformation of the guideway under atmospheric environment and the dynamic characteristics of the deformed beam while the vehicle passing are studied.Temperature deformation of the guideway primarily depends on the selection of the temperature gradient mode and the temperature design value. Different temperature modes are adopted in different countries. Nowadays, the research results on temperature effect of the box girders are mainly targeted to highways and railways, which are characterized by long flange and relatively small height and the web is totally in the shade under the general sunshine angle. However, the maglev box girders (guideways) are very different, whose web is high and flange is narrow and the web is exposed in sunshine directly. Temperature action makes the guideway produce deformation, which will aggravate vibration of vehicle-guideway system. So it is necessary to do deep research on temperature deformation and its influence on vehicle-guideway vibration.The general principle and method of temperature deformation analysis in highway and railway are referred and stricter requirement on deformation of maglev guideway is considered. In order to improve the precision, a new boundary condition called‘mixed boundary condition’is applied. With finite element simulation, the guideways applied in Shanghai maglev line with different axis orientation are analyzed and more suitable temperature mode is found out. Analysis results indicate that the sunshine temperature gradient mode of the special-shaped cross-section maglev guideway is different from that of T-shaped girder in highway bridges and box girder in conventional railway.The coupling vibration analysis model is built depending on German maglev vehicle. The continuously distributed magnetic force and the characteristics of its active control are considered and continuous structural model of guideway is adopted in this model. In order to analyze the vibration response of the simply supported guideway while vehicle passing, vehicle including 5 carriages and 30 simply supported guideways are considered and the response of the 26th guideway is taken as the result to analyze. The calculation program with FORTRAN is worked out with the model described above. The vibration response of the simply supported guideway used in Shanghai line is analyzed. The relations between the dynamic response of the guideway and the parameters of the vehicle and guideway, such as vehicle speed, guideway span, guideway deformation are discussed. It can be concluded that the guideway generated upward movement under temperature action in the sunshine. The greater temperature deformation of the guideway leads to greater impact coefficient when vehicle passes the guideway at lower speed. However, when the speed exceeds 340km/h, the greater temperature of the guideway leads to smaller impact coefficient. The impact coefficient and acceleration of the guideway are prone to increase with the increasing of the speed. It can be concluded that the dynamic characteristic of the guideway used in Shanghai line is good.The vehicle-guideway interaction model considering the influence of temperature deformation in the dissertation can be referred in the guideway design.