Fatigue Analysis And Application On Multi-MW Wind Turbine Key Parts

In the past decades, along with the drain of fossil energy, more and more attentionis paid to the wind power which belongs to clean energy. With the development ofglobal wind power industry, some problems of wind turbine come out gradually. Duringthe last ten years, there were hundreds of wind turbine accidents at home and abroad, alarge portion of which are caused by fatigue damage. Lacking of relevant technologies,wind turbine manufacturing enterprises paid little attention to fatigue analysis in China.It is of great value to improve the designing and manufacturing level of wind turbine inChina by analyzing the fatigue damage of key parts of wind turbine accurately.The dissertation proposes a study entitled “Fatigue Analysis and Application onMulti-MW Wind Turbine Key Parts”, which was sponsored by the National Science andTechnology Support Projects named “the Design and Demonstration of5.0MWDoubly-fed type VSCF offshore Wind Power Units”(2009BAA22B02).Based on thefatigue analysis of a MW-level Doubly-fed type VSCF offshore Wind Power Unitswhich is produced by a famous wind generator producer in China, the fatigue damage ofshaft and bolts on wind generator was analyzed in this paper. The shaft and bolts are keyparts of a wind generator. All the analyses are based on Germanischer Lloyd standard ofwind power, A practical method of fatigue analysis was proposed in the paper at last.The main contents of the paper are as follows:①At first, the basic knowledge of fatigue analysis was elaborated, including thefatigue damage mechanism of metal, the measurement of fatigue and factors which havegreat impact on fatigue life. Otherwise, how to improve the fatigue life when practicallydesigning or producing a machine part was also pointed out in the paper. This work isthe base of the subsequent research.②In the paper, a feasible method of fatigue analysis of wind power generator wasproposed. According to the discussion of several multiaxial fatigue theories and thecompetition of several common fatigue damage cumulative rules, the failure methodwhich suit the key parts of wind turbine best was got in the paper. By using the softwareof Bladed, the wind generator model was simulated and the fatigue load time historywas got. The fatigue load spectrum was acquired through processing the fatigue loadtime history by using modified rain-flow counting method. The fatigue load spectrumoffers the input data for the subsequent fatigue study of the wind generator parts. ③The main shaft fatigue life was analyzed in the paper. In order to get the fatiguedamage of main shaft, the finite element model and material model of main shaft wereestablished. Through the fatigue load spectrum and finite element model, the shaftfatigue damage under fatigue load was calculated. These works provide a practicalmethod of fatigue damage calculation for such kind of parts.④The paper also conducts a systematic analysis on high strength bolts which isused for connecting the foundation embedded and tower. By using Schmidt/Neuperbolts fatigue calculation model, the fatigue damage of bolts under actual condition wascalculated. This approach was of great reference value for the choice and check of windturbine bolts.