Study On The Abnormal High Frequency Vibration And Its Influence

From the national railway planning from four vertical and four horizontal to the present eight vertical and eight horizontal,our country railway is in a period of rapid development.The operation scale of the high-speed railway is more and more large.The number of the high-speed rail EMU that open is increasing and the speed is continuously increasing.High-speed rail EMU in high-speed operation,the wheels appear polygonal wear,rail corrugation aggravate and other issues.Poor wheel / rail matching causes high frequency vibration of wheel / rail during high speed operation of the EMUs,resulting in jitter of the vehicle body,damage to parts of the vehicle's bogie,deterioration of body comfort,reduces stability and seriously has an impact on the safety.In this paper,the problems of high-frequency vibration are first reviewed.The track irregularity and wheel-rail contact theory were analyzed.Take some type of EMU for testing,the use of experimental equipment m / wheel on wheel for non-roundness measurements before and after the repair.The result shows that there is 27 order polygon with the maximum amplitude of 13dB(0.0045mm)at the 3 axes of the second car,and the main vibration frequency is 548 Hz at 200 km / h,the high polygon disappears after the repair.This type of EMU is tested.The results show that the overall state is good.The maximum vibration acceleration of the front and rear wheels on the measuring point is 56.31 g.the maximum vibration acceleration of the axlebox is 31.88g;Horizontal and vertical vibration acceleration maximum 0.36 g and 2.3g;body transverse,vertical maximum stability of 2.06 and 3.11;a series of vertical maximum displacement of 10.4mm.The main frequency of axle box,frame and axle are found as follows: the bending frequency of wheelset is 80 Hz,the frequency of polygon of wheel 26 ~ 27 is 540 Hz,the frequency of orbit wavy of wavelength 80 mm is 720 Hz,the natural frequency of EMU is 800 Hz,Wave length of 60 mm ~ 70 mm rail wave mill frequency 800 ~ 900 Hz.Excluding the electric brake operation test,At this time,the vibration acceleration of the disc hub,the axle box and the brake beam did not appear abnormally large.In K1724 and K1952 sections Emergency braking did not occur abnormal vibration.Brake beam there is an equal interval when the main frequency of the brake.The vibration accelerations of K1770 ~ K1830 section are obviously larger than those of other sections.The vibration acceleration is dominant at 800 ~ 900 Hz and the corresponding orbital wavelength is 60 ~ 70 mm.The vibrational section of 800 ~ 900 Hz The vibration frequency is transmitted from the axle and the hub to the axle box and the frame,and the frequency is obviously reduced when the frequency is transmitted to the vehicle body.The orbital vibration test results show that the downward force of the orbit is greater than the straight line.The frequency analysis of the vibration accelerations of the rail,bar(fastener)and rail plate found that the main frequency of the rail is 940 ~ 1100Hz;the main frequency of the bar is 510 ~ 550Hz;the frequency of the rail plate is similar to that of the rail.Lathing the straight track measured elastic strip exists around the 560 Hz frequency before repair,the frequency disappeared after repair.The wheel rail reduces the vibration,reduced by 15% ~ 66%.