Misalignment in multi-spool bearings acts as a preload between the rotors and has a similar effect as predeformation in springs. Therefore, modeling misalignment requires adjustment of the relative motion between the shafts. Let u1 and u2 be the displacements of the shafts at the bearing center, and θ1 and θ2 be the corresponding tilt angles. For a parallel misalignment u0, the relative displacement between the shafts is given by

For an angular misalignment θ0, the relative angular displacement between the shafts is