The Thermal-structural Coupling Analysis For The Brake Of Wind-Turbine Generation

The brake is a key part of wind-turbine generation. Nowadays the brake of wind-turbine generation in China relies mainly on imports and the domestic market shares are controlled by foreign brands. The braking is a complicated process involving multi-physics. The research on the braking process not only can better understand frictional mechanism of the brake, but also have significant impact on breaking the foreign monopoly and develop independent innovation brand.Based on SVENDBORG brake of hydraulic factory and combined with theoretical foundation of thermal-structure coupling, the paper establishes the numerical model for the brake and simulates this model and simulates the temperature field and stress field of the disc and pad according to this model. The results reveal the regularity of difference and distribution of the temperature and Von Mises stress and temperature gradient for the disc and pad during the braking.Firstly, the paper introduces the basic theory of thermal-structural coupling. It includes the establishment of temperature field for the brake, the finite element method of transient temperature field, the finite element calculation of thermal stress and the introduction of the method of thermal-structure coupling.Secondly, the numerical model of the temperature for the brake is established. According to the working condition of the brake, the hypothetical condition of the temperature field for the brake is proposed. In accordance with actual structure of the brake, the thesis establishes the geometrical model of disc and pad in ANSYS software and confirms the initial conditions and boundary conditions of the model on the basis of actual condition. After calculating the thermal loading of disc, the paper confirms physical performance parameters, motional parameters and thermal parameters.Furthermore, based on the numerical model of previous temperature field, the paper simulates the temperature field with ANSYS finite element analysis software. According to the rotating motion of disc when emergently braking, the thesis comes up with a method of iterative calculation to load the heat flux. The results reveal that the temperature distribution of points in the frictional region of the disc is from non-uniform to uniform and later from evenly to non-uniform while the distribution of the counterpart in pad has obvious contour lines in radial direction. Finally, the stress field of the brake is simulated. Since the general unit cannot achieve large rotation in ANSYS, in order to simulate the deceleration movement of the disc, this paper adopts 184 Element to drive the brake. Under the consideration of the mutual coupling relationship for the temperature field and stress field, it puts forward a method of step-by-step loading to calculate the stress field of the disc and the pad. The conclusion shows that the Von Mises stress distribution and the temperature distribution of disc is basically the same while that of pad are different.The analytical method in the paper could supply reference for later researchers on the simulating of frictional braking process and the calculation results provide a basis for further analyzing the mutual coupling relationship of the temperature field and stress field and developing high-performance wind-power brake.