Mechanical Characteristics Analysis Of Wind Power Yaw Bearing Based On Collaborative Simulation

The yaw bearing of wind turbine can adjust wheel and blade’s azimuth to make it alignment with the direction of the wind and working under axial load, radial load and tilting moment together, the bearing is working with low speed and overloading. The yaw bearing’s operating conditions is very scurviness, and the installation or replacement is expensive, so mechanical properties of the yaw bearing should be studied. The mechanical properties analysis of bearing includes two aspects:the contact characteristics between rolling element and rings, which influence the stress of contact surface and the surface inside cause fatigue failure; The flexible deformation of bearing rings and its supporting structure would cause the change in contact load and contact angle of rolling element, which affect the contact stress distribution indirectly., this article mainly studies the influence of contact characteristics and flexible deformation on the mechanical properties.First, the contact behavior between bearing rings and rolling element is studied, and introduced the calculating formula of relationship between the contact load and the relative approach with Hertz contact theory. And contact stiffness between the rings and single rolling element is obtained by formula conversion. The local finite element model of the bearing is built with ANSYS software; the elastic and elastic-plastic analysis is developed. The contact load, maximum stress and the elastic relative approach are obtained with local finite elements model and Hertz contact theory, and compare the two calculation results. Respectively, the elastic-plastic analysis is based on the elastic modulus of bearing materials and real stress-strain relationship. The study finds the relationship between contact loads, contact stress and the elastic relative approach in contact behavior. The relationship between contact loads, contact stress and the elastic relative approach is derived through interpolation and fitting, contact characteristic equation is established according to the relationship.Secondly, a calculation model is built, which consider the flexible deformation of bearing support structure and rings on large rotary bearing. The flexible deformation compatibility equations of bearing are derived, which consider the effect of bearing support structure and flexible deformation of ring on raceway curvature center. The multi-degree of freedom statics equilibrium equation is set up to determine the contact load distribution of rolling body. A simulation method which couple the theory and finite element, through MATLAB calling ANSYS looped and paralleled. MATLAB iterate arithmetic theory, calculate the output of displacement caused by deformation of flexible change though ANSYS and implementing the data transmission through intermediate text document. And studied contact load, contact Angle and groove center displacement of 2.0 MW wind yaw bearing through the calculation model under load case. The bearing test bench and displacement testing method are designed, processing experimental data, compare the analysis of rigid, flexible model and experiment, and found the relationship and difference with the measured data. With the experiment, the analysis of bearing mechanical characteristics with theory-finite element combined method is verified.