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!

*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.

Jobs

Joint Separation Analysis

Joint Separation Analysis

(OP)
Hi,

I refer to Joint Slip Analysis for fasteners. One reference for such an analysis is NASA-STD-5020.
I have been wondering if there is merit to apply this analysis beyond bolts, and on countersunk fasteners.
Can countersunk fasteners slip?

I'm questioning this because I have been tasked to prove that all fasteners used in my design, including countersunk screws, satisfy the non-slip condition.

Thanks!

RE: Joint Separation Analysis

Be careful that you have the proper load capability for your flush head fasteners. Because of the penetration of the recess, many of these designs are down rated on their tensile strength to account for failure through the head prior to full potential load being reached. most flush head parts are designed for non-structural or shear loaded applications where they are used in shear, rather than for use in slip-critical designs.

RE: Joint Separation Analysis

I don't recall any part of NASA-STD-5020 prohibiting use of flush head fasteners. The joint-slip analysis approach described in section 6.4 is for "Friction as a Load Path for Shear Loading". This relies on axial preload in the joint fasteners to create sufficient clamped friction at the joint interface to prevent any relative sliding between the contact surfaces. I think it would be safe to assume that if there is sufficient axial preload in the fasteners to meet the joint-slip safety analysis margin, then there should be more than enough friction at the flush head bolt contact to prevent any sliding there.

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close