Lifting Device for Hub of a ۴.۵ MW Wind Turbine

Rotor hub is one of the major components of the windturbine, which is subject to all the blade’s weight andwind loads. This component is utilized to connect therotor blades to the drive train. Lifting of the rotor hubwith hub cover should be carried out by a special tool inworkshop. The lifting tool should be modeled anddesigned according to the specified strength criteria byconducting the finite element (FE) analyses. The toolwas supposed to construct from the low-carbonstructural steel S۳۵۵JR, which is widely used in themanufacture of various structural and mechanicalcomponents. This material is a weldable steel withsuperior mechanical properties. Since the material isregarded as the ductile material, for the purpose of staticstrength analyses, the maximum shear strain energyhypothesis, i.e., von-Mises stress criterion was applied asequivalent stress to survey the failure condition andfinding the safety factor of the designed tool. The rotorhub’s total weight was estimated about ۵۰ tones. Therewere some FE analyses to attain the final modifiedmodel of lifting tool. The investigated models wererevised in such a way that the weak sections werestrengthened and the unnecessary materials (with lowstress values) were removed to reduce the tool’s weight.The final model with total weight of ۶.۵ tones and safetyfactor of ۲.۹ was obtained. The M۴۲-۱۰.۹ bolts withpreload of ۴۴۸ kN were selected according to the bolts’calculations.

Keywords:

Wind turbine , Lifting device , Rotor hub , FEanalysis.