Multi-objective optimization for dynamics parameters of high-speed trains under side wind

To improve the dynamics property and the running stability and safety of high-speed train under side wind, the wheel shaft lateral force and the wheel load reduction rate were taken as the optimization goals, the multi-objective optimization design for the suspension parameters of high-speed train dynamics model was carried out, and the multi-body dynamics parameterized model of high-speed train was modeled. According to the wind speed limit standard, the aerodynamic data of high-speed train under side wind at different speeds were loaded. Total 11 variables were extracted such as the stop clearance, the first suspension longitudinal and vertical stiffnesses, the second suspension longitudinal and vertical stiffnesses, the first vertical shock absorber stiffness, the second lateral and vertical shock absorber stiffnesses, snake-resistant shock absorber stiffness and damping. The high-speed train dynamics model optimization platform was built. The correlation between the design parameters of multi-body dynamics parameterized model of high-speed train with the wheel shaft lateral force and the wheel load reduction rate was carried out, and the influence trend of suspension parameters on the wheel shaft lateral force and the wheel load reduction rate was obtained. Based on the correlation results, the optimization design for the high-speed train dynamics parameters was proceeded by using the NCGA, AMGA, and NSGA-Ⅱ genetic algorithm. Analysis result shows that the optimization result of NSGA-Ⅱalgorithm is ideal. The factor that has the biggest correlation with the wheel shaft lateral force and the wheel load reduction rate is the snake-resistant shock absorber stiffness, and with an adverse effect. After the optimization, the dynamics property of high-speed train has a marked improvement. The wheel load reduction rate decreases from the origin value 0.78 to 0.63 wholly, and the minimum value can be 0.49, reducing by up to 37.2%. The wheel shaft lateral force decreases from the origin value 16.8 kN to 9.6 kN wholly, and the minimum value can be 5.79 kN, reducing by up to 65.5%. The Pareto frontier optimal solution is got, the optimal solution set of each dynamics parameter design variable is determined, and the optimal solution sets with high applicability are verified at other wind speed and train speed states. 3 tabs, 14 figs, 33 refs. © 2020, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.