×
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

Stress transformation question

Stress transformation question

Stress transformation question

(OP)
I have normal stresses in x, y, and z along with shear stress in x-y. I am rotating the coordinates about the z axis, so the normal stress in the z direction should be the same in the new coordinate system as in the old.

My question is, since the stress in z does not change, and since all the other stresses are in the x-y plane, can I use the stress transformation equations attached? They are clearly labeled as being useful for "plane stress and plane strain" situations only(http://en.wikipedia.org/wiki/Stress_%28mechanics%29#Stress_transformation_in_plane_stress_and_plane_strain), but the stress in Z really doesn't seem to have anything to do with the other stresses here.

Any help is appreciated.

RE: Stress transformation question

i haven't read the wiki article, but ... plane stress and plane strain are "just" two extreme stress states ... plane stress, typically for thin panels, has 2D stress (ie no stress thru the thickness) and 3D strain (due to poission); plane strain, typically thick plates, has 2D strain and 3D stress since the thick plate creates stiffness thru the thickness.

your equations are correct for rotating stresses in-plane.

RE: Stress transformation question


Yes you are correct.

These equations are simply Mohr's Circle.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

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