Research On Fatigue Test For Levitation Chassis Of High-Speed Maglev Train

The high-speed maglev train can effectively supplement the inter-city railway network system,and it can further improve the point-to-point transportation demand between cities.As one of the important components of high-speed maglev trains,it is necessary to carry out in-depth research on its structural reliability.This paper studies the fatigue test method of a high-speed maglev train levitation chassis independently researched and developed in China,and provides a basis for the reliability design of the high-speed maglev train magnetic levitation mechanism,and has certain guiding significance for the indoor fatigue test of the levitation chassis.In this paper,the structure and corresponding functions of the levitation chassis of high-speed maglev train are introduced.The characteristics of the levitation chassis and the force transmission route are analyzed.The difficulty of the finite element model of the levitation chassis and the constraint mode and loading mode of the finite element calculation are determined.By comparing the advantages and disadvantages of each method of pre-tightening force,bolt and riveting connection,the equivalent efficiency method and the coupling and constraint equation method are combined to solve the overall connection problem for the hundreds of bolts and riveting parts of the levitation chassis.The finite element model of the levitation chassis is established according to the finite element modeling principle.Secondly,the common load types of the levitation chassis are introduced in detail,and the static strength,fatigue strength and modal calculation of the levitation chassis are calculated according to the 14 kinds of abnormal load conditions and 8 kinds of operational load conditions.The results show that the basis is the fourth strength theory evaluates the static strength of the levitation chassis.The maximum stress position appears at the pendulum of the vehicle body and the Z-direction support.The maximum stress values of other parts are less than the allowable stress of the respective materials;the multi-axial stress is utilized.The uniaxial stress method was applied,and the fatigue strength of each substructure was evaluated by modifying the Goodman fatigue limit diagram.The stress and stress amplitudes of all key points on the levitation chassis were within the modified Goodman fatigue limit of 6005A-T6 and ZL101A;the mode is 14.07Hz,and the excitation frequency of the whole high-speed maglev is generally around 8Hz.The natural frequency of the first-order mode is much larger than the excitation frequency,which effectively avoids the resonance phenomenon;the static strength and fatigue of the levitation chassis both strength and modal calculations meet design strength.Then,according to the loading position and restraint mode of the levitation chassis,the levitation chassis fatigue test bench is constructed.Refer to the high-speed magnetic levitation design load conditions and the UIC 615-4-2003 standard to determine the static strength test and fatigue strength test load conditions,and the test point patch position is determined according to the finite element simulation result.Develop a test result evaluation method and complete the study of the fatigue test method of the levitation chassis.Finally,based on the quasi-static stress analysis method,the fatigue life calculation software is used to compare the damage of the key parts of the levitation chassis under the test load with the damage in the actual road condition.The results show that the large damage position of the levitation chassis calculated by the fatigue test method can cover the large damage part of the levitation chassis under actual working conditions.The fatigue life calculated by the two methods meets the design life.The suspension fatigue test method designed in this paper can effectively reflect the reliability of the levitation chassis under actual operating conditions.