Calculation of a lumped mass at either of the bearing station mB
The mass is calculated out of equivalence of supporf loads caused by a stiff rotor and by the mass mB.
md , Jd - disk mass and transverse moment of inertia; w - speed of rotation.
Load P can be interpreted as a mass load reduced to the support:
Then the loads equivalence gives
Then the reduced mass can be calculated
If the rotor includes k inertia elements, their total reduced mass is
a - orbit radius of shaft due to a support flexibility