Add a Rotor Coupling node to model the coupling characteristics between two rotors. The selection for this feature is a point on the rotor where the coupling is located.

Select Coupling type — Spline, Torsional, or User defined. Then, go to the relevant section below to continue defining the properties.

Enter the value of the Torsional stiffness, kθ,ax. This coupling type connects displacement and tilting rotations across the two rotors on interior points and axial rotation of both rotors are connected by a spring of stiffness kθ,ax. On exterior points, displacement and tilting rotations are free. The axial rotation is connected by a spring of stiffness kθ,ax relative to an imaginary fixed point.

Select Displacement connection — Rigid or Flexible. In the Flexible case, enter the Translational stiffness, ku. The displacements in the two rotors are connected by a spring with the specified stiffness. In the Rigid case, the displacements in both rotors are rigidly connected. On an exterior point, the other rotor is assumed to be fixed.

Select Axial rotation connection — Flexible or Rigid. In the Flexible case, enter the Torsional stiffness, kθ,ax. The axial rotation in the two rotors is connected by a torsional spring with the specified stiffness. In the Rigid case, the axial rotations in both rotors are rigidly connected. On an exterior point, the other rotor is assumed to be fixed.

Select the Bending rotation connection — Flexible or Rigid. In the Flexible case, enter the Bending stiffness, kθb. The bending rotations in the two rotors are connected by a spring with the specified stiffness. In the Rigid case, tilting rotations in both rotors are rigidly connected. On an exterior point, the other rotor is assumed to be fixed.

Physics tab with Beam Rotor selected: