Statics modeling of a stand

Project Support
1

Hello all,

I am trying to model an stand that I created for an engine that weighs ~3000 lbs. The axial length of that engine runs parallel to the ground, while the stand itself is perpendicular to the ground. I’m not entirely familiar with SimScale but I am shocked to see such low stresses in my results, so I just want to make sure I didn’t make any mistakes,

I’ll explain each boundary condition here:

Fixed support 1/2: This pin actually rests on a beam that goes straight toward the ground, so I figured fixing it here should be okay-- I am not particularly concerned about the stresses in that beam.

Remote force 5: I’ve placed this remote point such that it reflects the CG of the engine itself, then applied a force of -3205 lbf to represent the weight of the engine.

Here is a link to my model: https://www.simscale.com/workbench/?pid=7204410065080168187&mi=spec%3A405d2de9-55ee-4bde-9577-6f32dcde8b4c%2Cservice%3ASIMULATION%2Cstrategy%3A1&ps=analysis%2FboundaryConditions%2F2

Please let me know your thoughts, I appreciate it.

2

Hi @jciccosanti, thanks for posting

Quick suggestions:

  1. Insert the gravity on the -y direction under “model” to account for the mass loadings from the assembly
  2. Replace the force by a point mass
  3. Change the deformation behavior to “Undeformable” instead of deformable, this will make the connection between the point and the faces stiff

Cheers
Igor

3

Thanks for the reply, a few questions on that note:

As a response to your point #2, what are the advantages of using a point mass rather than a remote force? I had originally considered that but figured it would make more sense to apply an actual boundary condition rather than a weight as I thought it might help with convergence.

I am also wondering how making the deformation behavior to undeformable will change the results

4

Hi @jciccosanti, the suggestion to go for a point mass + gravity is mostly because of consistency - I think this makes it clearer that you’re attaching a weight. The effect should be the exact same as the force (for the static case).

Regarding the Deformable / Undeformable question, this makes a bit more difference. Since Undeformable makes the connections stiff, we should expect 2 effects:

  • The faces will not change shape (as if they were “glued” to these spider like elements) - which seems to be desirable.

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  • The simulation will be more efficient and stable, as the “deformable” option creates new chalenges that need to be addressed (since now the faces are free to deform).

Cheers