| Research on the dynamics and fatigue reliability of rail transit vehicles under the wheel-rail adhesion effect.Rail transit vehicles have the advantages of strong carrying capacity and high transportation efficiency and become the main force of public transportation in medium and large cities.However,with the increase of load capacity and operating speed,the transmission system As the core subsystem of the whole vehicle,its internal and external excitations make the dynamic characteristics and fatigue reliability of the transmission system particularly complicated.Since each platform needs to start and stop frequently for about one kilometer adjacent to each other,the stick-slip characteristics of the wheel and rail will change under the excitation of track irregularities and complex and changeable operating conditions,and the drastic fluctuation of its adhesion torque will affect the meshing of gears.Response and cause vibration and shock to the transmission system,and the nonlinear factors of the gear itself will in turn affect the stick-slip characteristics of the wheel and rail,thereby affecting the reliability of the gear and leading to serious safety accidents.Therefore,research on wheel-rail adhesion characteristics to the dynamic characteristics and fatigue reliability of the transmission system has theoretical guiding significance and engineering practical value for improving the safe and smooth operation of rail transit vehicles.This article uses the metro wheel rail-transmission system as the research object,and the adhesive torque caused by the adhesive characteristics of the wheel track.Based on the Polach contact model and dual-linear model,it proposes to consider the wheel pair under the rail interface factors and the conditions of large creep conditions at the same time.Twisting the vibration rail sticky model.Consider the internal and external incentives of the gear transmission system,and establish a multi-freedom dynamic model of the wheel-rail-gear-bearings coupling of the metro transmission system.Through the response of the dynamic model output,based on non-linear fatigue damage,the theory Considering the remaining intensity of the remaining intensity Gear fatigue reliability model,and solve its reliability indicators and reliability through the swimming method.The main research content is shown below:(1)Different wheel/rail creep models are summarized and their applicable working conditions and shortcomings are compared and analyzed.Finally,the calculation accuracy and time of four wheel/rail creep models under different creep rates are solved,providing research ideas for the following transmission system dynamics models considering wheel/rail adhesion torque.(2)The adhesion characteristics of metro are analyzed.Based on the bilinear model of wheel rail adhesion characteristics and the Polach contact model,the adhesion torque equation is derived.Taking into account factors such as wheel rail nonlinear adhesion torque,time-varying meshing stiffness of gears,nonlinear backlash,bearing support force,and track irregularity excitation,a multi degree of freedom dynamic model of a gear bearing transmission system considering wheel rail nonlinear adhesion torque load is established,Analyze the vibration response characteristics of the transmission system under different adhesion conditions and different parameters.(3)By establishing a dynamic model of the transmission system considering internal and external excitation and solving its dynamic response,the limit state function of gear fatigue reliability is established based on the nonlinear fatigue damage accumulation theory,and finally the fatigue reliability and reliability index of the gear are obtained. |
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