| Since Ministry of Railways of China launched the global tender for EMU trains on June 17,2004,CRRC has successively taken steps in importing,digesting,absorbing and re-innovating international high-speed railway technology monopolies such as Kawasaki,Bombardier,Alstom and Siemens.China’s high-speed rail technology has rapidly developed to a world-leading standard.The terms like High-speed railway,Hexie railway,Fuxing railway,etc.are familiar to the Chinese today.Subway,light rail and intercity railway have been embedded into the fabric of everyday life for the Chinese people.The fact that the rail transit technology prove to be one of national symbol,and win credibility and support from the Chinese people,is attributed to rail transit technology’s excellent reliability,comfort,safety and speed.Air spring,which is a key component of secondary suspension system in railway vehicles,is affected by high frequency of multiaxial loading during the actual working condition.The accuracy of the prediction on the life span of Air spring is critical.In consideration of aging phenomenon of the air spring rubber,and based on the theory of fracture mechanics and crack propagation theory,the paper analyzes the fatigue life of air spring.The main works are listed below:(1)This paper explains the fatigue damage and aging mechanism of rubber materials,and expounds the factors that affect the fatigue properties and aging properties of rubber materials.It also introduces the fatigue life prediction method based on cracking energy theory,and material aging prediction method based on time-temperature superposition principle;(2)Various material constitutive tests,fatigue tests and artificial accelerated aging tests were carried out.Data processing software is developed to assist in data processing to improve the efficiency of data processing and the consistency of results.The material constitutive model,fatigue model and aging model were established based on a large number of test data,which provided basic material data support for subsequent finite element simulation and fatigue calculation.(3)Finite element simulation and fatigue analysis of air spring were carried out based on ABAQUS &Endurica system.The fatigue life of air spring under a certain load spectrum is predicted,and the fatigue danger point is given.The fatigue life is about 16 years according to conventional calculation.(4)Considering the aging of rubber materials,the fatigue life was calculated.The calculated results showed that the ozone attack life was about 15 years,and the thermal oxygen aging life of the material was 11.9594 years.Considering the aging,the life span is about 1.2 times of the actual life span,which is about 66% less than the life safety margin of the conventional calculation method.The results show that the whole method has a certain reference value for the design and development of rubber elastic elements. |
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