Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Interesting Joint Stiffness Method

  1. Jun 5, 2010 #1
    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 I used a method suggested by another person with much more experience.

    Using Shigley's method, I found the bolt stiffness as so 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 longitudinal directional stiffness (2*Kb).

    The 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 used with it. Does anybody have any comments or thoughtful input on this method?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted