Research On Fatigue Life Of Track Slab Based On The State Of Track Irregularity

Under dynamic action between wheel and rail, the rail surface will produce uneven wear and rail head will appear abrasive damage local shortwave irregularity, at the same time, the track structure and rail elastic foundation uneven will cause long wave track alignment irregularity. With the increasing of the train by the total weight, development of track irregularity is directly related to the vibration state of the wheel rail system, so it can influence the track in long-term service performance. Therefore, it has important theoretical significance and practical value to study the development trend of track irregularity and to analyze the vibration characteristics and fatigue life of the track slab caused by wheel rail excitation.In this paper, the variation trend of the track irregularity is studied by using the theory of time frequency conversion and the traditional state probability, and the fatigue characteristics of the CRTSII type track slab are studied by using the method of multi body dynamics and finite element method.The main research contents are as follows:1. Through investigation and reference literature, it is concluded that the track irregularity prediction method is summarized, and the influence of track irregularity on the fatigue life of CRTSII type track slab.Based on the analysis and summary of domestic and international track irregularity forecast and track slab fatigue analysis method, the influence of the track irregularity wavelength on the fatigue life of the track slab is studied.2. Based on Wavelet and EMD theory and combined with the traditional state probability model, the establishment of the track irregularity prediction model is established.Two kinds of track irregularity prediction models are established, which are improved by using wavelet and EMD method respectively, to provide the source of non ride comfort for the following vehicle track multi-body dynamics model.In addition, the accuracy of the two methods and the prediction accuracy of the prediction method of the traditional state probabilities are compared, and their advantages and disadvantages are analyzed.3. A vehicle track multi-body dynamics model is established, which can analyze dynamic response of the rail, In addition, a coherent analysis of the track irregularity wavelength and the dynamic response of the track is carried out, which can find the unfavorable wavelength range of the irregularity.Using SIMPACK software to establish the vehicle track multi-body dynamics model. Through the model simulation, obtain the vibration characteristics of vehicle track system and the load time history of track system by using the method of numerical calculation. In addition, making the use of coherent analysis and other methods, to find the range of the non smooth adverse wavelength, through the reconstruction of the negative wavelength, analysis of track irregularity wavelength on the track board fatigue life.4. The finite element model of II CTRS type track slab is established, and the fatigue life of the track is analyzed, and the dangerous area and fatigue life of the track slab are determined.CRTSII model was established by the finite element software,create working conditions and load time history of the load time history of the fulcrum of the track system which is obtained by the above analysis software.Miner fatigue accumulation theory and S-N curve fatigue analysis method are used to analyze the fatigue life of the track plate and the easy to produce damage area. In addition, making the use of the above negative wavelength of the track is not smooth, and using the same method to analyze the fatigue life of the track board, so as to explore the track irregularity wavelength on the track board fatigue life.