Displacement and Rotations in Solid Rotor
Bearing coefficients are specified in space-fixed directions, which are local to the bearing. Because the Solid Rotor interface is formulated in a co-rotating frame, the displacements are observed from a rotating frame. This displacement field should be transformed to a space-fixed frame before evaluating the average displacement and tilting of the connected boundaries. Let
u
1,r
and
u
2,r
be the displacement fields of the rotors in their respective co-rotating frames. The space-fixed displacement field can be obtained as:
where
R
is the rotation matrix corresponding to the axial rotation and
θ
1
and
θ
2
are the corresponding axial rotations of the rotor.
Average displacement and rotations of the connected surface can be obtained as:
where
r
c
is the center of the connected boundaries and
The Beam Rotor interface is modeled in a space-fixed frame. Therefore, there is no need to do any transformation to get the displacement in a space-fixed frame. Also, both displacements and rotations are degrees of freedom in the Beam Rotor interface. These are directly used for connecting the respective points.
