Research On Vibration Characteristics Of Small Radius Curve Section Of Urban Rail Transit Underground Line

As a common objective phenomenon,vibration exists in the universe and can be roughly divided into macroscopic vibration and microscopic vibration.Some vibrations can be described in a clear mathematical language,and some vibrations cannot be explained by certain mathematical formulas.Since the birth of the railway,the vibration problems have come into being.As a derivative of the railway,the subway naturally cannot avoid this problem.With the intensification of subway vibration problems,it has continuously restricted the rapid development of urban rail transit.Due to some subjective and objective factors,urban rail transit has a small radius curve segment more or less in the constructio n of the line.Because of the interdisciplinary problems related to mechanics,tribology,and materials science,the vibration problems involved in small radius curves were generally thought to be very complicated and difficult to understand.In order to find out the vibration characteristics in the track structure of the small radius curve section of the urban rail transit underground line,the main research contents in this paper are as follows:1)Review the researches on the vibration characteristics of the underground linear section and curved section of urban rail transit at home and abroad,and understand their research methods and research ideas on the coupled vibration of the urban rail transit underground line and track,and summarize them.2)Establish a finite element model for analysis.In the early stage,Solid Works was used to establish the three-dimensional model of the rail,and the modal analysis of the rail was carried out by ANSYS to obtain the corresponding vibration characteristics(natural frequency and vibration mode).Then establish the coupling dynamics between the curved section and the straight section with the SIMPACK.The simulation model simulates the dynamics of the train at the speed of 60 km/h in the straight section and the small radius curve section,and compares the vibration characteristics of the straight section and the small radius curve section in the frequency domain.3)On line vibration test of track structure.The vertical and lateral vibratio n accelerations of the rail in the 350 meter radius curve section of the underground line of urban rail transit are tested in the field,so as to verify the correctness of the results obtained by the software simulation of the wheel rail coupling dynamic model of the 350 meter radius curve line.The vibration of the rail is transmitted to the floor of the carriage through the primary suspension and secondary suspension.Therefore,the vertical and lateral vibration acceleration of the carriage floor of the 350 m and 550 m radius curve section and the straight-line section are tested.The relationship between the size of the curve radius and the vibration in the carriage and the vibration characteristics of the carriage floor with different curve radius can be obtained.4)Based on the comparison between the measured results and the software simulation results,find out the similarities and differences between the measured results and the software simulation results,and verify the correctness of the results obtained by the modal analysis and software simulation.