×
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

Interesting Joint Stiffness Method

Interesting Joint Stiffness Method

Interesting Joint Stiffness Method

(OP)
So I was doing some FE work (w/ NASTRAN) to determine the stiffness in all 6 DOF of a model bolted to another model. To characterize the bolted interfaces I attached surface nodes within the bolt frustums to rigid body elements (RBE2). Then, these RBE2s were connected with a directional stiffness element (CBUSH) to model the bolt. To determine the directional stiffnesses of the CBUSHs I used a method suggested by another person with much more experience. Details below.

CBUSH Stiffness Determination:

Using Shigley's method, I found the bolt stiffness as Kb = E*At/L'. Where At was the tensile area, and L' was the effective grip length.

Then, to approximate the surrounding material stiffness, I multiplied Kb by 2. This was the joint longitudinal stiffness (2*Kb).

The joint transverse directional stiffness was found by multiplying the longitudinal joint stiffness by G/E ~ 0.4 to get a short beam in shear vs. tension stiffness.

This is a method that I had never heard of, or thought of. But because it was based on industry experience, I rolled with it. Does anybody have any comments or thoughtful input on this method?

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