Calculation Of The Stress Intensity Factors And Analysis Of The Residual Fatigue Life Of Locomotive's Spring

Spring of primary suspension of locomotive is one of the main components. Its quality and service life have a great effect to the safety and reliability. With the coming of the high-speed railway era, people have more and more requirements toward train operation safety and its reliability as well as the bogie and the spring which is on the bogie. However, it was found that, during the actual running of the vehicle, even in the allowable stress, the fracture of the spring of locomotive may also occur.After long use, it was inevitable to produce some defects on the surface of spring, further more the spring loads in a very complex and constantly changing of the gross weight on rail working environment, these defects will be in the effect of alternating stress constant evolution to the formation of cracks, and finally make the spring break and failure.In order to study the fatigue performance of spring and to predict its fatigue life. This paper is committed to the analysis and research of spring of primary suspension of locomotive, including defect and no-defect in both cases. In this paper, we use the finite element stress analysis and the MSC.FATIGUE fatigue strength to analyzing the fatigue life of spring and the remaining fatigue life of crack spring. The main research works are following:1. First, describing the basic theory of cylindrical coils spring, so we could have a basic understanding of this spring;2. Secondly, we explain on the detail the theory of the fatigue and the crack growth of spring, in order to pave the way for the calculations of the fatigue life and the crack growth of spring.3. The last two chapters are the focus of this paper. First of all, the stress intensity factors of crack tip are calculated to determine whether the spring will break. Then, we have a detailed calculation and analysis toward the no-defect and the status with a crack using MSC.FATIGUE, for predicting the fatigue life and residual fatigue life. Finally, we obtain the size of critical crack, predict the time limit of service of spring with crack and provide a basis for maintenance and replacement of the spring.