Cosmos defining loads and constraints

Hi everyone,

My company is designing windturbines of 600kW. For ourcertification process, we need to do a series of FEA analyse.Currently i am working on the tower structure.

Constarints:
As some of you know there is a yaw bearing mounted on the towertop. The surface of the towertop which makes contact with thebearing, needs to be constrainted in a way that the entire surfacecan tilt or move horizontly and/or vertically. So no localdeformations.
The tower bottom is fixed.

Loads:
For the loads working on the towertop, i need to define a momentwhich will work on that constrainted surface. The points which larelocated far from the axis have to suffer more stress than the onescloser to the axis. It looks a bit like a bearing load, but thatthe force is higher as we move to the vertical plane.

Can please somebody help me to explain me if I need to define aconstarint plane and conect the surface at the towertop to this. Bydoing so simulated a constrainted surface? When i tried thisapproach Cosmos declared that i cannot implement a force/moment onconstrainted surfaces...

Pls help

Thank you in advance!

Sven
SolidworksSimulation