Study On Vibration Damping Mechanism Of Magnetorheological Damping Floating Slab Track

In this paper,based on the traditional floating slab track structure,the dynamic model of the magnetorheological damping floating slab track is established based on the modified Dahl model,and the dynamic response characteristics of the magnetorheological damping floating slab track under different excitation are simulated and analyzed.Based on the basic principle that the natural frequency of theexperimental floating slab track is consistent with that ofthe actual floating slab track,the experimental device of the magnetorheological damper floating slab track isolation system is designed.Through numerical simulation and field test,the vibration damping effect of the magnetorheological damping floating slab track isolation system in the low frequency range(especially near the natural frequency)is verified.The main research results and conclusions are as follows:(1)The Dahl model theory characterization method of magnetorheological damping correction is proposed.Combined with the nonlinear parameter identification method of energy method,multiple parameters are identified in batch and converted into linear problems.The identification process is simplified and the accurate results are obtained.It provides a precise and practical dynamic model for the application of magnetorheological damper in the floatingslab track.(2)When the magnetorheological damper is introduced,the rail force transfer rate of the floating slab is reduced in the whole low frequency range,especially in the vicinity of the natural frequency(10Hz),which is obviously less than that of the traditional floating slab track structure,and the maximum value is reduced by about 75%.In the condition that the external excitation amplitude is 20 kN,the total support force of the floating slab is reduced by 40% and 70% respectively and the vibration acceleration of floating slab is decreased by 4dB and 12 dB respectivelywhen the magnetorheological damping force is introduced near the natural frequency with 500 N and 1000 N.In the condition that the external excitation amplitude is 40 kN,the total support force of the floating slab is reduced by 20% and 40% respectively and the vibration acceleration of the floating slab is reduced by 2dB and 4dBrespectively when the magnetorheological damping force is introduced near the natural frequency with 500 N and 1000 N.The change of the external excitation mean value has little effect on the total support and vibration acceleration of the floating slab on the magnetorheological damping floating slab track after the introduction of the same magnetorheological damper compared to before.(3)According to the design parameters of the magnetorheological damper and the steel spring floating slab track,a reasonable magnetorheological damper floating slab track test device is made.The hydraulic servo dynamic loading device is used to carry out the dynamic loading test on the floating slab track equipped with magnetorheological damper.The low frequency vibration control effect of magnetorheological damper floating slab track is analyzed in the free vibration condition(especially near natural frequencies).The results show thatthe total support force and the vibration acceleration of floating slabrail using the magnetorheological damper are reduced by 80% and 20 dB near the natural frequency than that without magnetorheological damper under the free vibration condition.