| Chinese high speed railway is well known for its comfort.With the rapid increase of train speed,wheel-rail interaction is becoming more and more severe,which intensify the vibration caused by the wheel-rail interaction ineluctably.Lateral vibration of high-speed vehicles have a great impact on ride comforts.Thus lateral vibration reduction of vehicle body has always received wide attention by researchers all over the world.Nowadays,the passive hydraulic shock absorber is widely used in transverse vibration damping of the second train suspension at present due to its simple structure and low cost.However,the passive shock absorber is a compromise choice after comprehensive investigation of the track conditions,and it has poor adaptability to various vibrations.The active shock absorber reacts promptly according to the incentive changes,which is sensitive and efficient,while its energy consumption is huge and the stability is poor.The semi-active damper not only possesses the controllability of the active damper,but also has the characteristics of stable structure of the passive damper,which has been widely used in the engineering field.Among various semi-active shock absorbers,magneto-rheologica(MR)Dampers have been developed rapidly in the field of train vibration reduction in recent years because of their simple structure,high safety,rapid response,and small energy consumption.The occupant’s perception of the lateral vibration of the train is much greater than that of the vertical vibration.The transverse MR damper of the train second suspension is controlled by the control strategy to control the output force.The introduction of the control strategy can effectively control the transverse vibration of the train,but at the same time,it may intensify the lateral vibration of bogies and wheelsets,such as the skylight damping control strategy.Rail wear damage is closely related to the wheel-rail contact conditions,and even a very small axle lateral force can also lead to wheel derailment when the unilateral wheel load shedding is too large.It is worth exploring whether the use of lateral semi-active MR dampers in the second train suspension will aggravate wheel-rail contact and cause adverse effects on road safety and rail maintenance.In this paper,a parametric model of a MR damper(Dahl model)was established firstly in Simulink.The sinusoidal loading of the MR damper by a universal testing machine was simulated in Simulink,and the dynamic characteristics of its damping force were obtained,this result was compared with the result of universal tester’s dynamic test to verify the correctness of parametric modeling of the MR damper.Secondly,the single-degree-of-freedom K-V interaction model was established based on Simpack-Simulink,and compared with the single-degree-of-freedom K-V model using Simpack’s own force element modeling,which shows the correctness of the Simpack-Simulink interactive platform.Then,a dynamic model of high-speed train was established in Simpack,and the model of a controllable MR second-system transverse shock absorber was established using the Simpack-Simulink interactive platform.Finally,the comparative analysis of the second suspension with passive shock absorber and controlled MR damper high-speed train under different working conditions was conducted to explore the impact of MR damper on wheel-rail impact force.The results show that the wheel-rail contact force will not change significantly in the time domain if the second suspension of the high-speed train is equipped with a MR damper,but in one-third octave frequency domain,it can be seen clearly that below the center frequency of 5 Hz,the wheel-rail contact is effectively suppressed,and the wheel-rail contact will be aggravated in the center frequency range from 4 Hz to 80 Hz.In the higher frequency range from 125 Hz to 630 Hz,the wheel-rail lateral contact force under the role of the ceiling semi-active MR damper is sgnificantly larger than the value of hydraulic shock absorber,and the increased impact of high-frequency wheel rails may have an adverse effect on the normal service of the rail. |
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