Abstract
The effect of dynamic unbalance of the underframe suspended rotational equipment on the flexible vibrations of the carbody has become a major concern for high-speed trains. It is known from the field tests that the dynamic unbalance has a significant influence on carbody vibrations, especially the local flexible vibration, which leads to a decrease in the passenger ride comfort and may even cause structural damage to the carbody. A vertical mathematic model considering the carbody flexibility and the underframe suspended equipment is first set up, and then a three-dimensional dynamic model for a rigid–flexible coupled vehicle system is established. The effect mechanism of the dynamic unbalance on carbody flexible vibration is extensively studied, and the efficient measures to reduce the carbody flexible vibrations are proposed. The theoretical and simulation models are verified by comparing with a field test conducted on a newly designed high-speed railway. The results show that decreasing the unbalanced mass of the rotational equipment can reduce the carbody vibrations. Moreover, the use of elastic suspension for the underframe equipment can isolate the vibration transmission to the carbody. Both the theory of dynamic vibration absorber and dynamic unbalance should be considered to optimize reasonable suspension parameters, especially the suspension location and the suspension frequency.
Highlights
Along with the speed increasing of high-speed trains, one of the main concerns is the carbody lightweight design
The results showed that the carbody modal frequencies are increased obviously with elastically suspended equipment and reasonable suspension parameters can effectively reduce the carbody flexible vibrations
It indicates from the analysis result that the underframe equipment with dynamic unbalance should be located within 3 m from carbody center to obtain good vertical vibration performance of carbody
Summary
Along with the speed increasing of high-speed trains, one of the main concerns is the carbody lightweight design. The results showed that the carbody modal frequencies are increased obviously with elastically suspended equipment and reasonable suspension parameters can effectively reduce the carbody flexible vibrations. With the operation of high-speed railway trains, researches into vehicle system dynamics face new challenges, one of which is the influence of the dynamic unbalance of underframe rotational equipment on carbody flexible vibrations. Decreasing the rotational unbalanced mass can effectively reduce carbody flexible vibration, and regular cleaning is supposed to be useful to reduce carbody local vibration. To reduce carbody flexible vibration in the longterm service, there is a need to provide a theoretical basis for the design of carbody underframe suspended system with rotational equipment.
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