consider the Clevis fork domain (see here for an image https://www.traceparts.com/it/product/camloc-motion-control-h1-stainless-steel-clevis?CatalogPath=TRACEPARTS%3ATP01001005&Product=10-12112014-075680&PartNumber=084337) and the linear elasticity equation on it. What are suitable boundary conditions that can be applied on such a domain? Even the simplest possible ones are fine, as long as they have physical meaning. I tried to search on the net but I didn't manage to find a clear setup!


Let's call $u_D$ the displacement field and $f$ the load (the rhs of the equation). Also, let $A,B$ be the surfaces of the two holes of the clevis (where the pin is passing through) and $C$ the annulus at the front of the clevis.

If I understood correctly:

  • $u_D = 0$ on $A$ and $B$
  • $\sigma \cdot n=(1e6,0,0)$ on $C$
  • $f=0$

What I mean with the second condition is that a traction of $1e6$ is applied on $x-$direction.

Now, I need to provide boundary conditions for the rest of the boundary $\Omega \setminus (A \cup B)$. As the surface is kind of free, I think a homogeneous Neumann boundary condition should be correct, i.e.

  • $\sigma(u_D) \cdot n=0$ on $\partial \Omega \setminus (A \cup B)$


  • $\begingroup$ Have you tried conditions resembling: Point x shall not move, being attached to a very rigid structure. Point y shall have a load placed on it in a direction. $\endgroup$
    – Abel
    Aug 10, 2023 at 4:38
  • $\begingroup$ I don't understand what you are referring to with Point x and Point y, I'm sorry, could you elaborate? @Abel $\endgroup$
    – VoB
    Aug 12, 2023 at 9:10
  • $\begingroup$ You have points (or areas) where your clevis is prevented from moving in some way, and similarly where loads are applied. These are the boundary conditions. $\endgroup$
    – Abel
    Aug 12, 2023 at 12:35
  • $\begingroup$ Sure, what it's not clear to me is where you would locate those areas (with reference the attached figure). Sorry for not being clear! @Abel $\endgroup$
    – VoB
    Aug 12, 2023 at 22:53
  • $\begingroup$ The holes in the clevis. One set where the pin goes, and one where the rod threads in. These are also where other parts attach or make contact. Things that are far apart and not extremely massive tend to apply pretty negligible forces so look for contact surfaces... $\endgroup$
    – Abel
    Aug 13, 2023 at 0:16


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