Harmonic Response Analysis And Fatigue Life Calculation Of Aluminum Alloy Gearbox For EMU

As "China Speed" continues to move towards the world,the safety and reliability of its outstanding representative high-speed trains have attracted more and ore attention.As a key component of vehicle traction and braking torque transmission,gear box not only bears the torsional load,but also bears the vibration load which caused by wheel-rail excitation,which is very complicated during operation.In recent years,the speed of High-speed trains in China has been continuously improved,and the lightweight and stability requirements of EMU are also more and more stringent,which requires that the gearbox must have sufficient strength while reducing the quality.This paper carried out the harmonic response of the aluminum alloy gear box body under vibration load,analyzed the reliability of the gearbox under the excitation of simple harmonic load and calculated t the fatigue life under the standard load and vibration load.The main research contents as follows:(1)Establish the finite element model of the aluminum alloy gear box,calculate the gear box load according to the EN13749 standard,use ANSYS to calculate the stress response of the gear box body,and analyze the static strength and fatigue strength.(2)The modal analysis of the gear box body is carried out,obtained the natural mode frequency and mode vibration mode of the gearbox body by modal analysis,and analyzed the natural vibration characteristics of the gearbox body.The results show that the first natural frequency of the gearbox body is 635.64 Hz under constraints,and the vibration mode is transverse torsional vibration,which laied the foundation for dynamic response analysis.(3)Based on the modal acceleration method,within the range of the main vibration frequency of the high-speed train wheel shaft from 200 Hz to 700 Hz,conducted the simple harmonic response analysis of the gearbox casing under high-speed straight line,lowspeed straight line,and bifurcation passing conditions.Obtained the vibration response characteristics of the gearbox body under the excitation of simple harmonic excitation in different working conditions.Analyzed the structural strength of the gearbox casing and the resonance frequency of the casing under different excitation loads,which provides an important reference basis for structural design.(4)Carried out the fatigue life calculation of the gear box body,based on the stress response of the gear box body under standard load,and the the harmonic response analysis results under three working conditions which contains high-speed straight line,low-speed straight line and turnout through,calculated the fatigue life of gear box under different working conditions at the different cating level.