×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

The relationship between RPM and end load??

The relationship between RPM and end load??

The relationship between RPM and end load??

(OP)
Hello,

I can't seem to find the answer to this one.

I have a 1/4" rotating rod (12L14 Steel) extended 2" out of a double angle collet. At the tip of the rod I have a metal disk with dimensions 3" round, 1/2" thick and weighs 4 oz.

How can I determine a theoretical safe RPM for this load? Is there a relationship between the moment of inertia and RPM at the tip of the 2" rod (assuming all parts are concentric)?

Can anyone lead me to a book or online site that talks about this?

Thanks.

RE: The relationship between RPM and end load??

The normally accepted answer is that to avoid whirling, the safe RPM would be 80% of the natural frequency of the overhung shaft+disk in cycles per minute. The best way to get a rough idea of the natural frequency would be to measure it in the non rotating condition. In addition to the stiffening effect of the moment of inertia of the disk about a transverse axis, the flexibility of the chuck is an unknown and may have the opposite effect of reducing the natural frequency. A measurement would incorporate both these effects. However, gyroscopic stiffening effects will also influence the behavior in the rotating case. If you want a book which covers the theory of a thin cantilevered rotor, you could try "handbook of rotordynamics F.F. Ehrich". A detailed analysis is pretty complex.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources