Pitchmoment blade root

Hi All,
I was wondering if there is any mass component in the pitching moment (i.e. rootMz) of the blade. Looking at the attached plots produced with FAST7 (at 2m/s slow idling pitch is at 90°), I guess it is not as we would otherwise see a rotor position component in rootMz.

Is this a feature that comes with the new nonlinear beam blade model? will we be able to enter a blade element wise CoG at least chordwise?

Best Regards,
Florian
morewind

Dear Florian,

The blade structural module in FAST v7 and in the ElastoDyn module of FAST v8 do not have chordwise CoG offsets from the pitch axis. However, there is still a mass component to the pitching moment when the blade deflects, as discussed briefly in the following forum topic: http://forums.nrel.gov/t/blade-twist-deflection/734/1.

The new BeamDyn module of FAST v8 supports a much more sophisticated blade structural model, including full geometric nonlinearity supporting large deflection, with bending, torsion, shear, and extensional degrees of freedom (DOFs); anisotropic composite material couplings (using full 6x6 mass and stiffness matrices, including bend-twist coupling); and a reference axis that permits blades that are not straight (supporting built-in curve, sweep, and sectional offsets).

Best regards,