Numerical Analysis of a Segmented Wind Turbine Blade Using the Substructure Method

Abstract

The wind turbine blade segmentation development remains a tough challenge for constructors to reduce the blade manufacturing and transport cost. In this paper, numerical analysis is developed in order to study the dynamic characteristics of a segmented wind turbine blade assembled with a spar. The spar and the blade segments are assimilated to a shell structure with different homogeneous and isotropic materials. Accordingly, the three nodes triangular shell element DKT18 is adopted to model the blade. To reduce the problem size the Craig–Bampton substructure method is applied. This study covers the effects the of twist angle on the blade natural frequencies. To validate the accuracy and reliability of the proposed substructuring approach, numerical results obtained from the present study were compared with those determined by modal analysis using ABAQUS software. Results showed that the blade natural frequencies are not monotonically varying with respect to the twist angle which must be investigated to be well above the wind turbine system frequencies.