Extraction of equivalent beam properties from blade models


  • This article is a US Goverment work and is in the public domain in the USA.


A method is presented for extracting the equivalent beam properties from a finite element model of a wind turbine blade so that full aeroelastic models can be constructed more reliably. The method is based on applying unit loads at the tip of the blade and processing the resulting nodal displacements to generate the 6 × 6 stiffness matrices for the specified beam discretization. The finite element model can comprise shell and/or solid elements, but the use of shell elements with centroids offset from the surface has been shown to produce erroneous torsional stiffness values. The method includes all three-dimensional effects such as shear and warping as well as flap–twist coupling, and these are demonstrated in a series of validation examples. The process will accommodate blades with curvature in one or both directions and has the added advantage of identifying the centre of mass, elastic centre, principal directions and shear centre. Published in 2006 by John Wiley &Sons, Ltd.