Fracture analysis of high strength bolt in wind turbine

Abstract

During the operation of a wind turbine in a wind power generation limited liability company, the bolt connecting the blade and the paddle bearing broke. In order to find out the cause of fracture, a comprehensive test analysis was carried out on the connection bolt between the blade and the variable blade bearing by means of macro morphology analysis, chemical composition analysis, mechanical property testing, microstructure testing and fracture micro-area analysis. Experiments show that: the blade and blade bearing joint bolt fracture: was the main cause of the bolt in the operation process of changing, repeated impact of wind load and the effects of the alternating load blade rotation, along the severe stress concentration of thread form ascend a crack source and extension in fatigue, until the whole fracture failure.