Study On The Design Theory And Application Of Performance And Stability Of High-Speed Train Hydraulic Shock Absorber

Hydraulic shock absorber is one of the key components of high-speed train. It directly affects the running stationarity and safety of high-speed train. With the increasing speed of the high-speed train, in order to maintain its efficient and quick operation, the railway department wants to make hydraulic shock absorber for high-speed train more stable and not be replaced for a long time. And this is a hard work for researchers and designers of hydraulic shock absorber in world-wide. The stability of Hydraulic shock absorber are particularly prominent in China, causing hydraulic shock absorber of high-speed train depends almost entirely on import, and restrict high-speed rail career develop independently and rapidly. And the main reasons are a lack of in-depth studies of the high-speed train design theory for stability of hydraulic shock absorber and technique blocked in developed country, causing domestic high-speed train manufacturing enterprises can only rely on the traditional "trial & test & modify" mode of design and manufacture. It is difficult to meet the requirements for hydraulic shock absorber of high-speed train.The author carried out the following areas of study in order to change the currently status of high-speed rail hydraulic shock absorber design and manufacturing, such as:the high-speed train design theory and method for stability of hydraulic shock absorber, establishes hybrid equivalent parameter model (HEPM) of hydraulic shock absorber damping characteristics, based on response surface methodestablishes high-speed train hydraulic shock absorber 17 parameters design model. The quality and cost hybrid robust design model (QCROM) was proposed based on the robust design theoy. The test and evaluation method of performance stability for high-speed trainhydraulic shock absorber was proposed. And a performance evaluation system for high-speed train hydraulic shock absorber was formed. Then a high-speed train hydraulic damper industrial technology development process was established initially after the research results was translated into engineering application. And this topic provides the necessary theoretical guidance and engineering references for the high-speed train hydraulic shock absorbers to achieve independent design, development and production.The main research works carried out are as follows:(1) Analyzing the present situation of design and manufacture of high-speed train hydraulic shock absorber in China. The topic research contents was proposed based on the study status of high-speed trainhydraulic shock absorber which was analyzed from the following three areas:the application status of hydraulic shock absorber in high-speed train, comprising the performance analysis of hydraulic shock absorber and the robust application status of high-speed train hydraulic shock absorber performance stability.(2) Based on the equations of motion of viscous fluid, the shock absorber damping throttle loss of component models was established. A hybrid e equivalent model (HEPM) was established based on the integrating application of CAE technology and pointing out the advantages anddisadvantages among the traditional lumped parameter model, equivalent parameter model and distributed parameter model. That is calculation of damping characteristics based on mixed equivalent parameter model, the key underlying data based on CAE method to obtain, and verifying the validity of the model. This model not only increases the calculation efficiency of the damping characteristics, and improves its accuracy (compared with the test value, deviation less than 5%).(3) Studying the process of fitting hydraulic shock absorber parametric design model using response surface method and design method of determining parameters. And building the second-order response surface model of rebound and compression storke of "Valve plate" type hydraulic shock absorber, and verify the validity of the model.The qualityevaluation index of rebound and compression stroke response surface model were 0.995 and 0.986, both of them were far greater than the inspection standards (greater than 0.9). The effect was analyzed between 17 design parameters and damping characteristics based on the response surface model.(4) The "quality-cost" hybrid multi-objectiverobust optimization model (QCROM) for stability of hydraulic shock absorber design was built based on the response surface model for parametric design of hydraulic shock absorber and summarizing and analyzing the advantages and disadvantages of the three modern robustdesign method:loss model, response surface model and stochastic model. And this model was solved by using the interact using an iterative optimization methods.This model not only has the advantages of the traditional robust design, but also turning the multi-speed design goals of hydraulic shock absorber into a single design goal. Meanwhile, this model overcame the heavy reliance on the data of traditional robust design model for constraints and targets probability. And the model became more suitable for product design and development stage becuse of getting the mean values and tolerance values of design variables directly.(5) Combining the processes and methods of properties stability design,6 styles hydraulic shock absorber were designed and optimized by using the performance stability methods. The discussing target was the the secondary lateral "valve" type hydraulic shock absorber. The total cost of shock absorber was reduced to 86.5%. Designed by hydraulic shock absorber performance stability while lowering precision design variables, the damper quality (performance stability) was not declined, but improved (22.2%). At the same time, precisely because of reduced design variable precision machining, manufacturing cost was reduced greatly (13.3%).(6) Studying and preliminarily establishing the industrial design and development technology processes of hydraulic shock absorberfor high-speed train. The structural design method of hydraulic shock absorber and testing method of performance stability were studied. Aiming at the CRH3 imported hydraulic shock absorber damping characteristics, the damping characteristics of designed and manufactured seven velocity points of the three hydraulic shock absorbers meet the requirements. Finally, the temperature-rise tests showed that:the damping characteristics of hydraulic shock absorber would be influenced deeply by the ambient temperature; Comparing to rapid changes of oil kinematic viscosity caused by temperature fluctuations (2 orders of magnitude), the damping characteristic of hydraulic shock absorber was more stable (the biggest change around 50%). This property could meet the damping characteristics requirements of high-speed train running in the larger temperature difference place.