| The secondary vertical hydraulic shock absorber is an important damping element in the suspension system of high-speed train,and it has a crucial influence on the dynamic characteristics of the train system.At present,domestic and foreign studies on the vertical dynamic analysis and suspension parameter optimization of high-speed trains usually idealize the hydraulic shock absorber as a linear element in vehicle modeling.This approach not only cannot reflect the real working characteristics of the hydraulic shock absorber,but also cannot reveal the complex coupling relationship between the shock absorber and the vehicle system.This results in a certain error in the response of the vehicle model,and is not conducive to the dynamic analysis of the train system and the global optimization of the suspension parameters.In this paper,considering the nonlinear damping characteristics of the secondary vertical hydraulic shock absorber,the coupling modeling of the high-speed train was carried out by numerical simulation,and the problems in the parametric modeling of the shock absorber,the modeling of the vertical dynamics of the high-speed train and the optimization design of the suspension parameters were studied.The main work and innovative achievements are as follows:(1)A parameterized model of the hydraulic shock absorber with shim stacks considering the temperature effect was established.Considering the influence of ambient temperature,based on the actual structural parameters of the secondary vertical shock absorbers of high-speed trains,a parametric model of the shock absorber considering the temperature effect was established by using the fluid mechanics theory and the oil model,and its correctness was verified by bench tests,which can enrich the existing theory of shock absorber modeling and provide a model basis for the parametric modeling of the thermal-fluid-solid coupling high-speed train.(2)A parametric model of the thermal-fluid-solid coupling high-speed train was established.Using D’Alembert’s principle,a train vertical dynamics model considering the stiffness of the shock absorber nodes was established.Following the concept of system engineering,the thermal-fluid-solid coupling high-speed train parametric model was established.Based on the Newmark-β implicit integral method,the train model response solution method under random track excitation was presented.Using the Morris sensitivity analysis method,the influence of the parameters of the shock absorber valve system on the dynamic response of the train was investigated.It can provide an effective model tool for vertical dynamics analysis of high-speed trains.(3)A parameter optimization design method for shock absorber valve system based on the thermal-fluid-solid coupling high-speed train parametric model was constructed.Combining with the results of Morris sensitivity analysis,aiming at the running stability of the high-speed train,taking the running safety and locomotive shock absorber design requirements as the constraints,the parameters of the shock absorber valve system were optimized by using genetic algorithm,which can provide a reliable technical reference for the optimization design of suspension parameters of high-speed trains.Through software simulation verification,the reliability of the optimal design method of shock absorber valve system parameters based on the thermal-fluid-solid coupling highspeed train parametric model was verified.The results showed that the established optimal design method was correct.This study can provide a useful reference for the vertical dynamic analysis of high-speed trains and the optimization design of suspension parameters. |
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