×
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

Hollow torsion bar equivalent as solid bar.

Hollow torsion bar equivalent as solid bar.

Hollow torsion bar equivalent as solid bar.

(OP)
Cheers all,

I am currently using a hollow torsion bar (splined on both ends) with an OD of 1.125" and an ID of .875". What dia. solid bar would give me equivalent performance.
I know this formula is in Shigley somewhere, but I cannot find it.

Thanks in advance,
Jason Miyamoto

RE: Hollow torsion bar equivalent as solid bar.

If u recall the elastic torsion formula relates to the polar monent of inertia:
J=1/2*Pie*c**4
Equating the solid J (Js) to hollow J (Jh)
Js=Jh
1/2*Pie*Rs**4=1/2*Pie*(Rhouter**4 - Rhinner**4)
Rs=1.004 inch

RE: Hollow torsion bar equivalent as solid bar.

(OP)
Thanks for the post boo1,
The fact that going to a solid bar will require an increase in dia. was not what I was expecting.

Thanks

RE: Hollow torsion bar equivalent as solid bar.

The answer should have said that the new OD was 1.004 inches for the solid torsion bar.  Note, however, that the solid torsion bar has twice the area (and twice the weight) of the equivalent hollow torsion bar.

RE: Hollow torsion bar equivalent as solid bar.

Boo1,

What kind of Pie? I suppose you were meaning π or pi, right?

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Hollow torsion bar equivalent as solid bar.

How do you add the special char to posts?

RE: Hollow torsion bar equivalent as solid bar.

Boo1,

Click on the Process TGML link and scroll down to the Special Characters section.

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

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