Performance Analysis And Structural Optimization Of Yaw Bearing Based On The Thin Plate Theory

Compared with the ordinary bearing, yaw bearing has the structural features of large size, big load and small stiffness, considering the structure and operating characteristics of the yaw bearing, the axial flexible deformation of the ring becomes a factor that cannot be ignored in mechanical analysis. Therefore, it is of great significance to establish the mechanical analysis model applicable to large yaw bearings along with consideration of axial flexible deformation. Based on the thin plate theory, the formula for solving the axial flexible deformation of the yaw bearing is derived and the mechanical analysis model in view of the axial flexible deformation is established in this thesis; on this basis, the main structural parameters of the yaw bearing are optimized by using the static load capacity and the fatigue life as the optimization objectives. The research results provide a theoretical reference for the structural optimization design of the yaw bearing.(1) The development background, domestic and foreign research status, structure and work characteristics of yaw bearings are introduced, and the research contents of this thesis are presented. The Hertz contact theory, the thin plate theory and the L-P fatigue life theory are discussed, and some important formulas are deduced.(2) A solution of bearing ring axial flexible deformation calculation method is proposed based on the thin plate theory, on the basis of the calculated axial flexible deformation, the mechanical analysis model of yaw bearing is established, whose solution has been solved by the adoption of the single rank inverse Broyden iterative method along with Newton-Raphson iterative method, the calculation results of this method are contrasted with the results of finite element method and rigid theoretical method, the results are between the finite element method and the theoretical method, which proves it is more reasonable compared with the rigid theory.(3) The static load capacity of the yaw bearing is calculated respectively by the empirical formula, the rigid theory and the flexible theory, after which the calculation results has been contrasted as well. The effects of the bearing ring thickness, bolts distribution circle diameter, initial contact angle, number and diameter of rolling elements and osculation on the static load characteristics are analyzed. Aimed at the static load ability of the yaw bearing, the optimization mathematical model is established, and the genetic algorithm is applied to optimize the main structure parameters of the bearing.(4) The solving process of fatigue life in DG03 is elaborated in this thesis. Based on the L-P theory and flexible mechanical analysis method, the fatigue life analysis model for the design of the structure parameters of the yaw bearing is established, and this model is adopted to analyze the effects of initial contact angle, number and diameter of rolling elements, osculation on the fatigue life. A mathematical model of structural optimization with the aim of fatigue life is established, and some parameters are optimized.(5) By the method of introducing the weighted coefficient, the multi-objective optimization mathematical model is set up with the static load capacity and fatigue life as its objective, and some structural parameters of the bearing are optimized as well.