×
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

Stresses in hollow pins
2

Stresses in hollow pins

Stresses in hollow pins

(OP)
Will someone please tell me the formulae for calculating shear and bending stresses in hollow pins.  My old textbooks only discuss solid pins.  Can you suggest a good reference book?

Thanks

Albie2

RE: Stresses in hollow pins

for a solid pin

S = F/A = F/(PI * r^2)

for a hollow pin

S = F/A = F(PI * (ro - ri)^2

not much to it...

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

RE: Stresses in hollow pins

Try STRENGTH OF MATERIALS; by J. P. Den Hartog, Dover Publications (June 1, 1961);ISBN: 0486607550

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

RE: Stresses in hollow pins

for bending stresses, there's only a change in I ... if you can calculate this for a solid bar, you should be able to do it for a tube.

for shear stresses, the same formulae applies for solid bars and tubes (VQ/It) ...

RE: Stresses in hollow pins

RB57 has the rigth approach for bending stress calculation.

RE: Stresses in hollow pins

for a hollow pin

S = F/A = F(PI * (ro^2 - ri^2))

essentially you are subtracting the area of the hole
from the area of the solid pin to get the rim
area as the above formula indicates.

RE: Stresses in hollow pins

for a solid pin

S = F/A = F/(PI * r^2)

for a hollow pin

S = F/A = F(PI * (ro - ri)^2

I agree to wes the formulas are listed above

RE: Stresses in hollow pins

Why are you multiplying the force with the area?

S = F/A
For a hollow pin:
      A = PI*ro^2-PI *ri^2 = PI *(ro^2-ri^2)
(NOT PI * (ro - ri)^2)

and

S=F/(PI*(ro^2-ri^2))

RE: Stresses in hollow pins

That slipped by me too.
Thanks gearguru!

RE: Stresses in hollow pins

2
The shear resistance of a tubular member not subject to other modes of failure actually approaches half of the value stated, i.e., S=2F/A.

I've always understood this as the near-vertical side walls taking the shear (as in the web(s) of an I or box beam), where the top and bottom portions do most of the work in bending.

RE: Stresses in hollow pins

Swearingen,
Could you give the resource for that conclusion?
Interesting!
It does seem that there would be some difference
as to whether it was a thin vs heavy cross section
and/or rim thickness vs diameter.

RE: Stresses in hollow pins

I've been using that equation for years and once saw the derivation, but a quick look in my library found this one:

AISC Steel Construction Manual, 13th Edition, Spec. Chapter G6, Round HSS.

"The nominal shear strength, Vn, of round HSS, according to the limit states of shear yielding and shear buckling, is
         Vn = FcrAg/2 "

Fcr is the critical buckling stress and depends on D/t ratio, Ag is the gross area, and HSS stands for Hollow Structural Section which pertains to a specific type of pipe used in structures.

Note that the AISC spec is not intended to design watchband pins and the like, but I've used it for hollow pins as small as 1/2".

My first post alluded to other failure modes such as local buckling;  this equation and the ones further along in the text take those issues into account.  However, if you have a good feel for the material and proportions of the pin and know it won't fail in those modes, I think the S=2F/A number is a good one to compare to the yield stress.

RE: Stresses in hollow pins

Swearingen
Thanks!

RE: Stresses in hollow pins

It depends in how many places on the pin is the shear applied.
If in 2, then the swearingen's formula is what I would use also. If in one location only, then I'd prefer to use mine formula.

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