The Modeling And Experimental Research Of Belt-grinding Process In Rail Grinding

As a major means of railway maintenance technology, rail grinding can polish and repair the corrugations and fatigues from the rail surface. Because of lack of grinding process mechanism and factors of rail-wheel, it is difficult to enhance the rail grinding efficiency in the process of rail grinding, even cause rail abrasion and safety risks and so on. At the same time, the rapid expansion of railway transportation has made this problem more prominent. Therefore, abrasive belt as a major grinding tool has been applying to rail grinding in this thesis, which establishes the theoretical model between rail grinding depth and rail grinding processing parameters, and explores the influence law of processing parameters and particles characteristic on grinding depth and grinding efficiency, and provides theoretical supports for rail grinding and researching grinding equipment.Based on the mechanism of action between abrasive particles and rail in the process of rail grinding, the theoretical model of single grain cutting rail is set up and the process of particles cutting is simulated by means of the finite element method. This provides basic conditions for building the model of rail grinding depth. The causes of different wear types of abrasive belt are researched, which provides the theoretic foundation for analyzing the influence of wear process on the grinding efficiency. Based on the basic form of abrasive belt grinding and rail grinding requirements, the basic scheme of rail grinding with abrasive belt is proposed.Abrasive belt surface topography model in rail grinding is established, which builds foundation for researching the material removal process of rail grinding with abrasive belt. First of all, the distribution of abrasive particles is expressed by mathematical relation. The random distribution of abrasive particles in the space is obtained through configuration rules of abrasive particles and random vibration algorithm. Then the abrasive belt surface topography is acquired through random adjustment of the size and location of abrasive particles as guidelines that all of the generated abrasive grains don’t produce interference by compiling the computer simulation program. According to the grain protrusion heights distribution, the above modeling approach is validated by measuring the actual abrasive belt surface topography.Based on the abrasive belt surface topography model with the random distribution of abrasive grains in space, the grain protrusion heights distribution is presented in order to establish rail grinding depth model. By making use of probability theory and elastic mechanics theory, it can be assumed that the contact between contact wheel and rail accords with Hertz contact theory. The rail grinding depth model is built based on the cutting process of abrasive particles finally. On the basis of the above theory, the influence law of processing parameters on grinding depth is analyzed. The rail grinding depth model is validated by the material removal experiment of rail grinding with abrasive belt. This provides theoretical foundation for scientific control of processing parameters.Through the rail grinding test table, the experiment of testing the grinding performance of abrasive belt catered to rail grinding is launched. The grinding ratio of abrasive belt used to rail grinding is tested. It turned out that the abrasive belt with coarse-grained ceramic abrasive can be used to grind rail as a major grinding tool. The influence law of processing parameters on grinding efficiency is analyzed by the experiment method. It provides foundation for improving the rail grinding efficiency.