A Study on the Mechanism of Carbody Shaking Phenomenon of High-Speed Trains

The carbody shaking phenomenon can greatly reduce the ride comfort of high-speed trains. To investigate the abnormal vibration feature and root cause of the carbody shaking phenomenon occurring on Chinese high-speed trains, extensive field measurements have been conducted on a Chinese high-speed railway line. A three-dimensional rigid-flexible coupling dynamic model of a high-speed vehicle is developed to reproduce the shaking phenomenon and reveal the key influence factors, in which the carbody is modeled by finite element (FE) method. The results show that the main vibration frequency peaks of the car-body lateral and vertical acceleration appear around 9.0 Hz, which is close to the natural frequency of carbody diamond mode. These frequency peaks can also be found in the accelerations of the bogie frames and axle boxes. It is also found that the worn wheel profiles increase the wheel-rail contact equivalent conicity, which can reduce the bogie hunting motion stability and induce the flexible resonance of carbody. This means the carbody shaking phenomenon is the vibration resonance of carbody diamond mode that induced by the hunting motion of bogies with worn wheel profiles.