Study On Stiffness Characteristics Of Air Spring Of Rail Vehicle

The stiffness of air spring greatly affects the safety and comfort of rail vehicles.In this study,the air spring of rail train is taken as the research object,and the theoretical mechanical model and finite element model are established around the air spring.Combined with the stiffness test,material performance test and simulation analysis of air spring in service,the main reasons for the change of air spring stiffness performance are studied,and the causes and influence mechanism of air spring rubber and cord material degradation are further studied,which can lay a theoretical foundation for the prediction method of air spring stiffness degradation law.The specific work and conclusions are as follows:In order to find out the main reasons for the stiffness and material degradation of air spring,fatigue test,high temperature aging test and coupling test of fatigue and high temperature aging are carried out.The test results show that the elastic modulus of air spring material decreases gradually under pure fatigue;Under the action of pure thermal aging and the coupling action of fatigue and thermal aging,the elastic modulus of air spring rubber and cord materials increases gradually;Compared with thermal aging,the degradation rate of elastic modulus of air spring material under the coupling of fatigue and thermal aging is faster.This shows that when natural air environmental load and fatigue load exist together,hot air aging is the main reason for the performance degradation of air spring,and fatigue load mainly plays a role in accelerating the natural air aging speed of rubber and cord materials.In order to study the aging law of air spring,the influence of aging time on the stiffness of air spring was systematically analyzed by using the method of accelerated aging test and finite element simulation.The accelerated aging tests of the whole air spring,the rubber material of the air spring airbag and the cord material were carried out respectively,and the laws of the static stiffness of the whole spring,the elastic modulus of the rubber and the cord material changing with the aging time were obtained;The finite element simulation model of air spring is established,and the influence of rubber and cord material elastic modulus and cord angle on the vertical and horizontal static stiffness of air spring is further simulated and analyzed by using the simulation model calibrated by experiments.The conclusions are as follows: the vertical static stiffness of air spring increases with the increase of aging time;The aging of air spring cord material and rubber material will increase the vertical static stiffness,and the latter will have a greater impact;The vertical static stiffness of air spring with cord angle of 25 ° is more stable during aging;The transverse static stiffness of air spring also increases with the increase of aging time,and is more affected by aging than the vertical static stiffness;The conical emergency spring helps to reduce the influence of aging on the vertical and horizontal static stiffness of air spring.58 Figures,47 Tables,88 References...