The Research On The Vibration Characteristics And Transmission Rules Of The 250 Km/h Chinese Standard EMU

The high-speed and light-weight design of high-speed EMU result in the increase of high-frequency vibration and widening of frequency band of various components of the vehicle system.When the track irregularity excitation and wheel irregularity excitation are transmitted to all parts of the vehicle system through suspension elements,the vehicle system is prone to local elastic vibration intensification and component instability.From this point of view,the vibration and transmission characteristics of the vehicle system will directly affect the safety and stability of the vehicle operation.So,it become significant for the research of vibration and transmission characteristics of high-speed EMU.The research's object of this paper is the 250 km/h Chinese standard EMU.The vibration dynamic characteristics and transmission rules of the Chinese standard EMU are studied through both field measurement and simulation.The main contents and conclusions are as follows:(1)Based on the measured time-domain data of vibration acceleration,the vibration characteristics of high-speed EMU bogie parts are obtained.The results show that when the speed is 250 kilometers per hour,the vertical vibration of the axle box and the motor is greater than the lateral vibration in the time-domain,while the vibration of each measuring point of the gearbox is larger than the vertical vibration.In vertical vibration transmission,the vibration of the axle box to the large gear box is attenuated,and the vibration of the axle box to the upper part of the gear box is amplified.In lateral vibration transmission,the vibration of the axle box to the upper part of gear box has been amplified.(2)Based on SIMPACK,different simulation models are established to analyze different vibrating response.The results show that the model of flexible components under the combined excitation is closer to the actual measurement by introducing the comprehensive excitation obtained from the measured data analysis.At different speed levels,the vertical and lateral vibration acceleration amplitudes and root mean square values of the main components of the vehicle system increase with the increase of the speed level;In the process of curve,when the excess is certain,the derailment coefficient,lateral vibration acceleration of carbody,wear index and wheel load reduction rate of the vehicle system decrease with the increase of the radius of the curve.The lateral vibration acceleration of wheelset and lateral force of wheel-rail have less change with the radius of the curve,while it becomes obvious when the train enters and goes out of the transition curve.In different transmission processes,the vertical vibration acceleration of each component of the vehicle system tends to increase,but the lateral change have no significant changes.Under uniform acceleration and variable acceleration conditions with equal average acceleration,the vibration acceleration response of each component during the same period of operation is affected by its average velocity;Under flexible track model,considering the wheel irregularity,the comprehensive excitation could stimulate a larger vibration response of flexible track model,and flexible track have a better reflection about the periodic vibration frequency of vehicle system caused by track plate length and sleeper spacing.(3)Based on the vibration data obtained by simulation,the transfer function of vehicle system is obtained by Fast Fourier Transform.The results show that the flexible component model has a great influence on the high frequency transfer characteristics in the condition of uniform linear speed,and the primary suspension is significant.Comparing the transfer functions of the primary suspension with secondary suspension,it is found that the secondary suspension is better than the primary suspension in the effect of vibration reduction,both of their reduction of vertical vibration are better than the lateral direction;the curve condition has a great affect on the lateral transmission characteristics of the vehicle system;the transmission rate in the high frequency range of the vehicle system is obviously increased and the frequency band is widened comparing with the uniform acceleration linear condition.The effect of uniform acceleration on the transfer characteristics of the primary suspension is stronger than secondary suspension,and the vertical acceleration have more effect than lateral acceleration.Generally,the modal vibration of vehicle system has a certain influence on its transmission characteristics.132pictures,21 tables,69 references.