Dear Philipp,
While BModes doesn’t directly output the polynomial coefficients needed by FAST, we’ve supplied the “ModeShapePolyFitting.xls” spreadsheet in the FAST archive to aid in the effort of deriving the polynomial coefficients.
Yes, those tower-top mass/inertia properties are correct for the NREL 5-MW turbine and the same values can be used for any tower modeled within BModes for this turbine .
The tower damping ratios used by FAST are described in my Oct 08, 2013 post in the following forum topic: Natural frequency and damping ratio calculation.
Best regards,