How to calculate Torsional Vibration
How to calculate Torsional Vibration
(OP)
I understand about lateral vibration, but how do you calculate (formulas) for torsional vibration of a tube?
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How to calculate Torsional Vibration
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How to calculate Torsional VibrationHow to calculate Torsional Vibration(OP)
I understand about lateral vibration, but how do you calculate (formulas) for torsional vibration of a tube?
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RE: How to calculate Torsional Vibration
RE: How to calculate Torsional Vibration
RE: How to calculate Torsional Vibration
If the tube is of non-constant cross section, you may want to use the Mykelstad-Prohl transfer matrix approach, and divide the tube into multiple mass elastic stations of constant cross section. Same approach would apply if calculating the torsional modes for a free-free supported tube.
Best regards,
Tom McGuinness, PE
RE: How to calculate Torsional Vibration
Putting the above posts into formula mode :-
wn=√ (To / I)
where wn=natural angular freq in rads/secs
To= torque per unit angle of twist
I = moment of inertia of oscillating mass
regards desertfox
RE: How to calculate Torsional Vibration
If you can supply more specific information on your problem we can help you more.
RE: How to calculate Torsional Vibration
Terve,
Aaron
RE: How to calculate Torsional Vibration
Basically what I am determining is the torsional frequency of a vertical shaft for a pump. You not only have to worry about lateral frequency but also torsional. You have to determine the Vane Pass Frequency (VPF) of the system. That is the RPM*# of Vanes of the impellar. The drive shaft torsional natural frequency (TNF) must be designed away from multiples (based on the # of vanes) of the operating speed and the speed of the pump itself.
I am trying to learn how to determine the TNF of a vertical pump shaft from single to multiple sections.
I've been pouring over the data left and it looks like you split the system into mass - spring - mass - spring, etc using the inertias and torsional stiffnesses.
RE: How to calculate Torsional Vibration
Cheers
Greg Locock
RE: How to calculate Torsional Vibration
Let us know how it works out.