critical speed for vertical shaft

[aftabhanifee]

Hello,
I have a problem as shown in attachment,here a vertical shaft is powered by a motor.
at the top of the shaft a circular disk is fixed weigh approximately 3 kg.
the shaft runs at 3000rpm and motor power is 0.75 hp.

Iam intrested to know the critical speeds within the working rpm range.( first ,second and may be more critical speeds).

i would be obliged if somebody helps out.
regards,
aftab

 

[GregLocock]

There is at least one crucial piece of information missing, namely what sort of boundary condition the motor represents. I assume that your textbook assumes fixed, radially.

If you were only interested in the first bending mode I'd suggest Rayleigh_Ritz, since the mode shape is obvious, but i must admit for the higher order modes I've forgotten how to do it other than FEA.


Cheers

Greg Locock


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[aftabhanifee]

@GregLocock
thanks sir for useful information.

regards,
aftab