# Shaft critical frequency



## BrianC (Apr 6, 2010)

When using f = 1/(2pi) * (g/delta)^1/2 to solve for a rotating shaft's critical frequency you can use beam equations to solve for the static deflection (delta). Is the static deflection calculated for the location of the weight or the maximum deflection of the beam?

I am specifically referring to 6MS machine design problem 70, where the maximum beam deflection does not coincide with the location of the 250 lbf gear. The deflection at the gear is used to solve for the critical frequency.


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## gaidox (Apr 6, 2010)

BrianC said:


> When using f = 1/(2pi) * (g/delta)^1/2 to solve for a rotating shaft's critical frequency you can use beam equations to solve for the static deflection (delta). Is the static deflection calculated for the location of the weight or the maximum deflection of the beam?
> I am specifically referring to 6MS machine design problem 70, where the maximum beam deflection does not coincide with the location of the 250 lbf gear. The deflection at the gear is used to solve for the critical frequency.


i know for static deflection in vibration prob. to use location of mass. it may or may not coincide with max deflection depending on location. again ,i dont have md sms to check it but merm 58.3 maybe helpful .


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## BrianC (Apr 7, 2010)

Thanks!! That is the answer I was looking for.


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