Damage Analysis and Optimal Analysis on Rail Pre-grinding Profile in High-speed Railway
|School||Dalian University of Technology|
|Keywords||Rail Monte Carlo contact Pre-grinding Profile optimization damage|
With the development of railway transportation in the direction of high-speed, heavy-haul and high density, rail damage caused by wear and rolling contact fatigue has been increasingly serious. Due to rail damage, Traffic and transportation accidents occurred frequently, which not only affects the safety of rail transportation, but also lead to serious economic loss. The results show that rail grinding can effectively improve the quality of wheel/rail profile, and extend rail service life. Therefore, it is the wheel/rail damage analysis and the optimal analysis of the grinding profile that has become a hot research topic, which needs to be implement quickly.The main task of this study is to research on the analysis of optimal rail pre-grinding profile, and predicting the rail damage location. The main achievements and conclusions are as follows:1. Wheel/rail contact analysis using finite element method. According to the actual shape of wheel/rail profile, boundary conditions and material properties, An finite element model of3D wheel/rail contact is established, basing on finite element software ANSYS. Through the analysis of contact stress state on different radius curved tracks and heavy-haul lines, it is obtained that when the upper rail of curved track is undertaking grinding, strip uplift which can cause contact stress concentration should be avoided.2. Optimal analysis of rail Pre-grinding profiles. Based on the method of tracing line and wheel/rail contact first order theory, an wheel/rail contact geometrical model is established and programmed. The model can calculate the contact points of different wheel/rail tread profile efficiently. Considering the lateral displacement of a rolling wheel on the rail, wheel/rail contact points often change, which lead to the uncertainty of the value and distribution of contact stress. Therefore, a wheel/rail probabilistic contact model is established. Firstly, based on Monte Carlo method, the random lateral displacement of wheel is produced, then, through the analysis of rail and wheel contact model and finite element model, a weighted index which both considering the accumulated contact stress and the average contact stress is proposed and used for evaluating the rail pre-grinding profile. A optimal profile is determined from four types of rail pre-grinding profiles which are designed by the engineering experience according to the weighted index, that is, the minimum value of the index for the rail pre-grinding profile.3. Rail damage location analysis. When the wheel moves transversely on the rail, the uncertainty of rail internal stress state makes it difficult to predict the fatigue damage position. It is assumed that random lateral displacement of wheel obey Gaussian distribution, through the wheel/rail contact geometry and finite element analysis, the internal stress state of rail is obtained. Then, based on the cumulative fatigue damage theory, the wheel/rail cumulative fatigue damage probabilistic model is proposed, and finally rail fatigue damage location is predicted.