Reliability Sensitivity Analysis And Robust Design Of High-speed EMU Traction Device

Traction devices are important connecting components transmitting tractive force and braking force between the body and bogie. Due to the error in manufacturing, installation and other processes, the structural dimensions、loads and material parameters of the traction device unavoidably contain random changes. Therefore, uncertainties also exist in the fatigue life of the traction device. Study the reliability of the traction device has great engineering significance.Strength and reliability of CRH2EMU traction device are studied in this dissertation. The analytical model of the traction device is established and the finite element analysis is carried out, the response value of the stress and fatigue life is obtained. The implicit limit state equation problem is solved by using design of experiment (DOE). The first-order second-moment method is employed to compute the traction device reliability and reliability sensitivity with normal distribution parameters. The Perturbation Method based Edgeworth series is used to analyze the traction device reliability sensitivity with arbitrary distribution parameters. The optimal design and reliability robust design are performed based on the reliability sensitivity results. The main contents of the paper are as follows:(1) The parametric model of the traction devices is built, HyperMesh is used to establish the finite element model, besides, the mixing cell finite element model of the traction support is built with the shell and solid hybrid element.(2) The structural strength analysis of the traction device is carried out according to the UIC615-1code. The fatigue life of the traction device is respectively predicted by applying the Goodman curve and the nominal stress method.(3) As the traction device has sufficient allowances for optimization, size optimization of the traction support and topology optimization of the traction rod are performed considering the structural characteristics of traction device, and the weight of the traction device is reduced through optimal design.(4) Sample values of the response and random variable are obtained by DOE, Kriging model is used to perform fitting to the sample achieving the response function with respect to the random variable. The limit state equations of the traction support and traction rod are built according to the stress-strength interference model, first-order second-moment and fourth-order moment method are employed to analyze the reliability sensitivity of the traction device.(5) By combining reliability optimal design theory and reliability-based robust design method, the reliability optimal design of the traction support is carried out by minimizing the volume of traction support. On this basis, the reliability robust design of the traction support is conducted by introducing the reliability sensitivity into the optimal design model, the reliability sensitivity is reduced and the volume of the traction support is minimized.