Analysis And Prediction Of Gears Fatigue In Large Wind Turbine Gearbox

Nowadays, the wind power is a new energy, which has been invested substantially by many countries around the world. And performance issues of wind turbine have also got attention of experts. As a core component of wind turbines, gearbox plays a decisive role to safe operation of the entire wind turbine. This paper mainly studies fatigue life of all levels gears, which belong to transmission of gearbox. Taking measured time-torque data of wind power gearbox as the basis, using probability and statistics, fatigue analysis, fracture mechanics, and finite element methods, we study the prediction of fatigue life and fatigue crack growth of all gears in wind turbine gearbox, which under random loads.Rain flow counting method was chosen to make statistical treatment of the measured data for each condition, and got time-load data finally. Then, this data was compiling into two-dimensional load spectra under different conditions. Then we analyzed two-dimensional load spectra to get the distribution of fatigue stress worked on all levels gears. Combining the measured frequency of conditions together, atwo-dimensional load spectra of multi-condition would be synthesized. Based on nominal stress method, Miner linear fatigue cumulative damage theory and Carten-Dolan nonlinear fatigue cumulative damage theory were used to estimate fatigue life of different levels of gears, then we can get the result that Carten-Dolan theory is safer than Miner theory. After that, based this analysis result, we studied the influence of several parameters to fatigue life of gears. In addition, from the perspective of fatigue crack growth, based on fracture mechanics theory, we used finite element analysis for representative planetary gear train and high-speed stage gears in gearbox, to forecast their residual fatigue life and verify the reasonableness of the last method.