Gravitational Influence on TipALz

Hi Everyone.

My question is concerned with the gravitational influence on tip-acceleration. In steady-state operation of my simulation I get a constant tip-acceleration which equals exactly the centripetal acceleration.
Unfortunately I don’t get the gravitational component in z-direction which should oscillate in relation to the number of revolutions. I can see the oscillations caused by gravity in the axial root force (RootFzb).

Thanks for your help!


Dear Kai,

You are correct. The accelerations output by FAST are the structural accelerations relative to the inertia frame; they do not include the gravity effect, which would add a constant downward acceleration equation to the gravitional acceleration. However, the gravity effect is included in all of the loads computed by FAST.

Best regards,