Fatigue Reliability Sensitivity Analysis And Reliability Robust Design Of High Speed Train Wheel

Train wheel, axles, bogie and bearing are important components for the safety of railway trains. With the developing of heave haul transportation and high speed trains, more and more problems happen in the field of reliability. So it requires higher reliability and longer service life of trains'travel parts to ensure the safety of traveling. There are many factors influents the reliability of trail wheel in the course of traveling and it is very difficult and may cost a lot to eliminate the impact of these factors. However, to reduce such impact is easier to realize while train wheel is working with a certain reliability. Therefore, a reliability-based sensitivity analysis is needed to make sure the reliability of train wheel is not sensitive to the change of these factors.To solve this problem, a deep analysis of fatigue reliability and reliability-based sensitivity of high speed train wheel is taken in this assay under the premise of a safe and reliable driving. Following are concrete contents:(1) Based on the load condition of the wheel, build parametric solid models of wheel and axle separately and set needed structural parameters on wheel model. Then, build a wheelset by assembling the wheel and axle which is to be analyzed in the following steps.(2) Based on the actual measured spectrum and actual parameters of locomotive body, obtain a load spectrum acting on wheel by theoretical calculating; make a strength check of wheel under static load using FEM method; and then, make a fatigue strength analysis under dynamic load, find the dangerous position on the wheel, get maximum stress-time history which is the needed stress spectrum.(3) according to the stress spectrum, the life of wheel is estimated to be about 2.7410×106km; by experimental designing and ANN training, fit a approximate function among maximum stress and structural parameters, based on S-N curve and Miner's rule, a explicit function among the life of wheel and those parameters is obtained; using kronecker algebra theory, matrix differential theory, second moment method and linear cumulative damage theory, reliability curve of fatigue life of wheel is obtained.(4) Calculate the fatigue reliability using Monte-Carlo method, by comparing the results with that obtained by second moment method, a fact is showed that the function used in the second moment method is accurate. According to the theory of reliability-based sensitivity, sensitivity curve of structural parameters is obtained. According to the curve, the sensitivity degree of different parameters on wheel is showed.(5) Based on the reliability robust design method, establish objective function of wheel mass and reliability sensitivity and constraint function of dimension. By computing, the optimized dimension and its reliability sensitivity are obtained.The results obtained in the assay provide theory support for the design and application of high speed train wheel in China; besides, it helps to reduce repair time, consume of material, number of extra needed wheels, and also reduce the failure frequency of trains. The obtained results have an important academic value and practical value.