Optimal design of dynamic vibration absorber for elastic vibration control of vehicle carbody in time-varying service environment

Due to frequent acceleration and deceleration and large passenger capacity, metro vehicles generally experience eccentric wear on the wheels. Moreover, the highest running speed is between 80 km/h and 100 km/h, and the corresponding wheel rotation frequency is mainly between 7 Hz and 11 Hz, which is close to the first-order vertical bending modal frequency of the carbody. Therefore, the dynamic performance of the carbody would be deteriorated in the later stage of wheel wear. In order to suppress the vibration caused by eccentric wear, this study intends to design the underframe equipment as a dynamic vibration absorber. Unlike the traditional fixed-point theory method, this paper takes the external time-varying running speed as the input, a suspension frequency optimal design method based on probability distribution of wheel rotation frequency is proposed. And the design principle is experimentally verified based on the full-scale railway vehicle vibration test rig. Compared with the design method based on fixed-point theory, the results show that the acceleration rms value of carbody by optimal design method is reduced by 8% ∼ 20%. It is suggested that the design of underframe equipment for metro vehicles should be combined with the characteristics of time-varying service environment.