| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 87 === To study the behavior of dynamic interaction between a traversing vehicle and its supporting structure, the vehicle is often represented by a set of concentrated forces if the traversing speed is low. For high-speed trains, a set of mass particles is often assumed to include the heaving inertia of the train, and represent the point contact between the wheels and the track. Although these vehicle models simplify the analysis, it also leads to serious questions regarding to the authenticity of the study.
In the present work, we propose a more realistic modeling of the high-speed train by using a set of multiple rigid bodies. Two-dimensional and three-dimensional models are formulated. Their responses due to dynamic interaction are compared.
Another important consideration is the operating condition of the trains, or the traffic condition on the supporting structure. Classical approach often assumes a constant speed and a single train. To study the possible critical traffic condition, we consider different combination of train operations, including a set of following trains and two trains cross passing each other.
Based on the assumed data, the present study shows that when a train speed reaches 150 KM/HR, the wheel contact force is about 50% more than the static wheel load due to weight. At 300 KM/HR, the force is about twice of the static load.
Our study also demonstrates that the motion of high-speed trains is smoother than low speed trains. Due to dynamic interaction, the vibration period of the train body increases as the traversing speed increases. This is in consistent with the common conclusion that passenger comfort improves at high speed traveling.
Numerical examples in the study are for a simple supported beam system. However, the model is formulated for general supporting structures. By introducing suitable influence functions, the analysis may be extended to study other forms of bridge structure.
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