In the design of large wind turbines with variable speed pitch control strategy
due to the effect of pitch and the differences in the load bearing characteristics of the bolts at different pitch angle positions
it is necessary to take into account the magnitude and the direction of the overturning moment of the blade root
and the pitch angle in the fatigue calculation of the blade root bolts. This paper introduces a three-dimensional interpolation method of stresses with load magnitude
direction and pitch angle as input variables to realize more accurate fatigue calculation of blade root bolts without increasing the amount of finite element calculation. Taking a manufacturer’s design as an example
the relationship between the blade root loads and the simplification of the calculation have been discussed. Finite element method was used for the bolt stress analysis. On the basis of FEM results
the three-dimensional stress interpolation and fatigue cumulative damage calculation of the bolt have been completed.
关键词
Keywords
references
IEC 61400 Part 1: Wind turbines-design requirements third edition2005-08[S].
ZHENG T S, CHEN N Z, YUAN L.Structural strength assessment for thin-walled blade root joint of floating offshore wind turbine (FOWT)[J]. Thin-walled structures, 2023, 191: 111057.
ZHENG T S, CHEN N Z.Time-domain fatigue assessment for blade root bolts of floating offshore wind turbine (FOWT)[J]. Ocean engineering, 2022, 262: 112201.
CHEN G C, WANG C Z, XIAO Z M.Effects of supporting structure and bolt connection on the fatigue life and carrying capacity of a slewing bearing[J]. Proceedings of the institution of mechanical engineers, part J: journal of engineering tribology, 2017, 231(6): 766-782.
DONG Z Y, ZHANG H L. Study on finite element model of bolt strength in blade root[J]. Applied mechanics and materials, 2013, 427/428/429: 221-224.
BUCHER C, EBERT M.Load carrying behavior of prestressed bolted steel flanges considering random geometrical imperfections[C]//8th ASCE Specialty Conference on Probabilistic And Structural Reliability. University of Notre Dame, USA, 2000.
LOCHAN S, MEHMANPARAST A, WINTLE J.A review of fatigue performance of bolted connections in offshore wind turbines[J]. Procedia structural integrity, 2019, 17: 276-283.