| The structure irregularity of rigid frog is the key factor of effecting the train passing speed and limiting its using range. Improving the wheel/rail contact relationship by optimizing rigid frog structure is benefit to improve the stability and the safety of the train passing over the turnout and the structure stationarity of rigid frog. Based on the theory of wheel/turnout contact relationship and wheel/rail system dynamics, the structure optimization and dynamic simulation of rigid frog were carried out with the following aspects:1. The establishment and program verification of a calculation method of wheel/rail contact geometry for rigid frogBased on the theory of wheel/rail contact relationship on normal track, a calculation method for the wheel/rail contact geometry in rigid frog zone was proposed and the corresponding software was developed. By using the automatic extraction of point coordinates in CAD, the rigid frog can be changed into space curve to analyze the wheel/rail contact relationship, which makes this method reliability; practical and feasible; the field test for wheel/rail concact point further validates the practicability and feasibility of the program.2. The establishment and the solution of vehicle-turnout of rigid frog dynamic coupling modelBased on the wheel/rail system dynamic theory, the structure of the rigid frog turnout was properly simplied, then the vehicle-rigid frog turnout space coupling system vibration model was established and the corresponding vibration equations were derived. According to this model, the simulation analysis program was developed to analyze the influences of the structure design parameters and irregularities to wheel/rail dynamic characteristics, which provide an important foundation for the optimization design of rigid frog wheel/rail relationship.3. The analysis of the wheel/rail contact geometry relationshipBy using the program of the wheel/rail contact geometry relationship, the variation regularity of the wheel/rail contact geometric parameters for the rigid frog of 60kg/m rail No.12 turnout was analyzed, which includes that the wheel/rail contact relationship along the longitudinal direction of the rigid frog without the consideration of wheelset sway and hunting; the wheel/rail contact characteristics of the key sections; and the wheel/rail contact relationship along the rigid frog with the consideration of wheelset sway. All the variation characteristics of the wheel/rail contact parameters showed the wheel/rail contact geometry features in rigid frog zone, and provided a guide for the selection of the structure optimization cases and the analysis of wheel/rail dynamic contact relationship.4. The comparison and selection of structure design parameters of rigid frog and the optimization cases designVarious optimization cases were proposed according to the key design parameters of rigid frog, the structure irregularities and wheel/rail contact parameters in all cases were analyzed and the influencing rules of all design parameters to the wheel/rail contact relationship were analyzed, and then the structure design parameters and their reasonable values were decided. So the analysis above can help to reach the aim of improving design efficiency, increasing the credibility of cases and promoting the scientification and the reasonability of wheel/rail relationship design and optimization.5. The dynamic evaluation of structure design parameters of rigid frogBased on vehicle-turnout space coupling dynamic theory, the influencing rules of structure design parameters to wheel/rail dynamic characteristics for rigid frog were analyzed; with consideration of all parameters, an optimization design case was proposed which can improve the safety and stability when train passes over the rigid frog; finally the influences of the speed and the axle load of train to the wheel/rail dynamic characteristics when the train passes through the rigid frog zone, which provides the basis to determine the proper service conditions for rigid frog. |
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