Experimental Study On Correction Coefficient Of Wind Turbine Bearing Damage Accumulation

The load of wind turbines bearing is generally time-varying load-time series. Influenced by the wind turbines running status and the natural conditions, load-time series usually have multiple cases and the data of each case is very large. To accurately estimate the life of wind turbines bearing, the information in the load-time series must be extracted reasonably. At present, the load-time serial is processed according to the following method. Firstly, cycle count method is used to turn it into multiple load spectrum. Secondly, the equivalent load of multilevel load spectrum is obtained by cumulative damage theory. Finally, the equivalent dynamic load considering each directions load is used to estimate the lifetime of bearing. However, the linear cumulative damage theory has some errors and the other theory because of the complex is not suitable for engineering applications. In order to provide a reference for wind turbine bearings reliability design, the linear damage theory is modified by the test method.On the basis of previous studies on wind turbine bearings fatigue load spectrum, this paper turns the large-scale wind turbine bearing load spectrum into test spectrum which is suitable for ordinary bearing by similarity theory. The paper finds out a method which can estimate the correction factor of linear damage accumulation by testing large-scale wind turbine bearing load spectra. It provides a reference for wind turbine bearings reliability design. Then, we get the correction coefficients of the linear damage theory in this way and analyze the relationship between it and the fatigue load spectrum characteristics. The result shows that it is inaccurate using the linear damage theory to estimate the life of wind turbine bearing; The load spectral characteristics will reduce bearing life; The Miner correction coefficient and the discrete degree of load spectrum is related; For the high reliability requirements of wind power bearing, it is necessary to do the equivalent test about the actual load spectrum, to determine a reasonable coefficient of linear cumulative damage theory.