Within the 'Bladknik' project new method for Buckling load prediction are develop for the FOCUS design package.

Buckling load analyses

Rotor blade buckling invloves bending in flat and edge direction, torsion and shear. The load combination that is most critical for buckling may be selected from several load cases in the design load set. For this purpose the Panel-based methods in Focus apply. If the most critical loading is found, more detailed analyses can be performed with FINSTRIP or with a FEM package such as ANSYS.

Panel-based methods

Fast, so suitable for searching the critical loading in a load-set. Influence of blade bending, torsion, and shear included. Improved for buckling of sandwich panels (shear web).

FINSTRIP for cross sections

Based on beam-theory, but includes the full structural integrity within a blade cross section. Integrated in Focus. Improved for asymmetric layup (still orthotropic). Faster eigenvalue solver included.

Interface to FEM package

FEM analyses have the most detailed structural representation, but require many CPU and effort to build an input model. FEM model can be generated with Focus. Option for ANSYS element SHELL181 (accepted by GL).


For inquiries please contact:

Knowledge Centre WMC
Kluisgat 5
1771 MV Wieringerwerf
the Netherlands
phone +31(0)227-50 49 49