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APPENDIX 2

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.

, aaa

; ;

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

Fig. A2.1

a - orbit radius of shaft due to a support flexibility

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