Strength analysis of MW wind turbine tower flange
                                  HE Hai jian, YANG Yang, MENG Ling rui, CHAO Guan liang, DONG Shu yan
                             （Xuchang XJ Group Wind Power Technology Company, Xuchang 461000, China）

Abstract: Aiming at the safety of tower flange in the MW wind turbine operating, take a certain high power level wind turbine top flange for example, the finite element model of the tower flange connection system which including top tower, top flange, bolts, washers, bottom flange and bottom tower was built up to analyze its stress distribution under the ultimate load case, and a new method which combines the critical plane method with shear stress method to calculate the fatigue damage of tower flange was then proposed in the tower flange fatigue strength calculation method study. The results indicate that the tower flange ultimate strength safety factor is 1.1, and its fatigue strength safety factor is 5.163, all of them above 1 and the critical locations are consistent with engineering practice, the tower flange can satisfy the strength design requirements according to Germanischer Lloyd standard. Besides, the results also indicating that the proposed method is feasible and reliable for tower flange strength calculation.

Key words: wind turbine; tower flange; strength calculation; finite element; critical plane