Static Analysis On High Strength Bolt Connection In The MW Wind Turbine Generator System

With the development of society, the energy and environment problems intensified.The development of new energy technology is the urgent problem needed to be solvedthat brook no delay. Wind energy as an inexhaustible green energy, is the futuredevelopment trend. But there are many incidents of large-scale wind turbine towercollapses occurred in recent years, and the most reason is the high strength bolts notmeet the strength requirements. The high strength bolt is one of the importantcomponents of the MW wind turbine generator system, played the role of connection,positioning and sealing, and its used amount is also the largest. How to explore therelationship between the high strength bolt preload and external load, as well as how toimprove the strength of the bolt connection, keep megawatt wind turbine safeoperation is a difficult problem to be solved at first. Therefore, it’s very necessary toresearch on the stress intensity and fatigue strength characteristics of high strength boltconnection.Therefore, this paper is supported by Key Laboratory of Regenerative EnergyElectric-Technology of Hunan Province Open Fund Project [2011KFJJ001]&School-Enterprise Cooperation Project―Research on High Strength Bolt ConnectionReliability of MW Wind Turbine Generator System‖. Taking a combination method oftheoretical calculations, numerical simulation, strength theory and fracture mechanicstheory to study the stress intensity, fatigue strength and surface crack propagation ofthe high strength bolt connection, the innovation and research work of the paper are asfollows:(1) Based on the bolt connection between MW wind turbine yaw gear and topflange, using VDI2230engineering algorithm to simplify the model, then a single highstrength bolt connection model was established to reveal the basic parameters of bolt,resilience of the bolt, residual pre-stress, load factor, losses of preload, minimum (max)preload, minimum length of engagement, tightening torque, et al. on the influencemechanism of high strength bolt strength and fatigue limit.(2) The FE model of bolt connection between flange and yaw gear was established,and the stress intensity&fatigue strength of the high strength bolt was analyzed byusing ABAQUS&FEMFAT, then obtained the distribution of stress, injury, life andother characteristic indexes of the high strength bolt connection, finally comparative analysis was done through the experimental.(3) The surface crack analysis model of high strength bolt was established, and thestress intensity&fatigue strength of the high strength bolt was analyzed underdifferent preload&crack shape, and then obtained the stress nephogram, fatiguedamage&life image and stress intensity factor of crack to verify the components meetthe design requirements.