Study On Seat Vibration Of Metro Vehicle

With the increase of population in the first tier and second tier cities,traffic congestion is becoming more and more serious.Therefore,more and more attention has been paid to the means of transportation,especially the public transport facilities,which are closely related to people’s lives.In this case,the subway has been developed.The subway has the advantages of fast running speed,no occupation of ground space,comfortable ride and low accident rate.While many cities are developing the subway,the safety and ride comfort of the subway have attracted more and more attention.Metro Line 4,due to the special line form,leads to larger traffic volume on line 4.The line is an important part of the city Metro.Recently,due to the jitter of seat when 4 line runs at high speed,the ride comfort and vehicle safety are seriously affected.In this paper,through the FFT and STFT treatment of the measured data of the subway line test,the vibration transmission relationship of the vehicle is studied.The results show that the main frequency of the vertical vibration of the axle box,frame,car body and seat has the vertical vibration of the 42 Hz.Comparing the wheel before and after repair,it is found that the main frequency has not disappeared.The modal of car body and seat is analyzed by ANSYS software,and the cause of vertical vibration of seat is established.The dynamic model of the subway vehicle is established by using SIMPACK software,and the low order polygon of the wheel is simulated.It is found that the vertical vibration of the seat is more obvious when the wheel produces low order polygons.Especially when the wheel produces 6 order polygons,the vertical vibration of the seat is the most intense.It is suggested that the structure and material of seats should be optimized.When the vehicle runs at 65km/h speed and the wheel generates 6 order polygons,the seat will generate vertical vibration.At the same time,the vertical vibration acceleration frequency of 42 Hz will be generated by axle box,frame and car body,which is consistent with the line test,and the seat jitter will be reproduced.It is proved that the seat jitter of Metro Line 4 is caused by low grade polygons.After finding the cause of the problem,the problem of the low-order polygon of the wheel cannot be solved immediately and effectively,so the focus of the research is on the structure and material optimization of the seat.Two schemes are proposed,the first one is the optimization structure and the other is the second optimization material.The two methods are modal analysis and response analysis,which verify the feasibility of the optimization scheme.