Easy natural frequency calc
Easy natural frequency calc
(OP)
Hi, I have a table that weighs around 600 lbs. How do I find it's natural frequency?
Thanks
Thanks
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Easy natural frequency calc
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RE: Easy natural frequency calc
If you can associate a stiffness with the mass, then w=sqrt(k/m).
If the deflection caused by gravity is representative of the vibration, then measure the static deflection and natural frequency can be calculated from that.
Most times a "bump test" is used to determine the natural frequency of something. You whack it with a hammer and measure the frequency of the response.
Also lots of computational techniques are available which would require a lot more info from you.
Not much help, huh? Any other commetns?
RE: Easy natural frequency calc
If you look in a mechanical engineering design book, you should be able to find a table of beam equations for the restraints in your situation and come up with a stiffness of the table. Figureing out how much of the tables mass is really contributing modally to a given natural frequency is another question.
I would be really interested to know why you are doing this.
Let me know if you want more help.
RE: Easy natural frequency calc
Thanks for the help. This table is to support several flexures that have an optics table on top. Acutuators attached to the table will provide tilt in the x and y directions. We just want to make sure that the frequency is higher than the one that we will be opporating with, something like 8 hz.
RE: Easy natural frequency calc
M
RE: Easy natural frequency calc
The only problem is you did not tell me how heavy the optics gismo on the table is, so I have not accounted for the modal weight contribution of the gizmo. If it is heavy that contribution might be significant.