高鐵列車行經高架橋樑時之橋軌與列車動態分析

Abstract

台灣高速鐵路於2007年元月通車，串起了西部走廊南北城市，為考量到高達300公里的時速，台灣西部人口的密集以及地形的起伏，全線有73%為高架橋路段。列車行駛時對於橋樑結構有特定週期的衝擊，所以高速列車對於軌道、橋樑造成衝擊的安全性，列車行駛時的安全性與舒適度提升等問題，以及降低高鐵對於環境的影響等皆為重要的研究課題。 本文依據台灣高鐵700T型建立分析模型，以剛體模擬車體，彈簧阻尼系統模擬列車主、次懸吊彈簧，轉向架以樑架模擬，鋼軌與箱型樑則分別以樑元素及板元素來模擬。應用ANSYS程式進行列車及橋樑模型的模態分析，了解其基本動態特性。利用LS-DYNA程式分析列車行駛於高架橋段時的動態反應，及列車對鋼軌、橋樑的衝擊反應，並將列車通過所造成的軌道橋樑加速度反應轉為功率頻譜密度，比較移動列車衝擊所激發的振動頻率與列車基本頻率與結構自然模態的關係。 最後將LS-DYNA分析的結果利用ISO-2631標準來評估列車運行在不同軌道不整度狀況下的垂向及橫向振動舒適度。

The Taiwan high speed rail started to operate at January 2007, and connects the cities between the south and north parts of west Taiwan. Because of the high speed train speed of 300 Km/hr, the dense population and the uneven ground level in west Taiwan there are 73% of whole line of high speed rail are constructured on the viaducts, which have the almost uniform span bridges, the rails pads with fixed distance, and therefore the travelling train will impact the rails and bridges with particular frequencies. The promotion for the safety of the tracks and trains are considered as the important problems since the railway was built. Recently, the riding comfort and the influence on the enviroment impacted by travelling high speed train have become big issues for rail dynamic problems. In this thesis, the train model is establishe based on the THSR 700T type train, in which the car body is considered as rigid part, spring and damping element are used for primary and second suspension systems, the bogies are modeled by strong beam element, rail and viaduct are simulated by beam and shell element, respectively. The dynamic characteristic of the train and bridges, are analyzed by modal analysis using ANSYS code. In this paper, we use LS-DYNA to analyze the dynamic response of train, rail, and bridges under travelling train condition. The calculeted acceleration of bridges and rail are transferred to power spectrum density (PSD) to find the singnificant frequencies and their relationship to the nature frequency and modal shape of train and structures. Finally the ISO-2631 standerd was used to evaluate the riding comfort using the analysis results under different class of track irregularity.