Applying a load in the middle of an open part

UGMENTALCASEUGMENTALCASE
Hi all,

I have a case where I would like to test a bracket I have designed. It holds a load around the horse shoe shape and the load centre is in fresh air (so to speak) It's been a while since I did anything on Mecway, but I seem to remember there being a way to do this?
Any suggestions would be great. I can get an idea of displacement by using the faces around the horse shoe shape, but I'd really like it to be more accurate (more for myself and learning a little more)

Thanks in advance

Comments

  • VictorVictor
    There isn't really a remote force or load distributing node-surface coupling like RBE3. CCX has that (*DISTRIBUTING) but it's sometimes wrong so I don't recommend it.

    Instead, you can apply the load to the surfaces around the edge and also apply a moment to the same surfaces to effectively move the line of action to where you want it.

    Or avoid that hand calculation and make a dummy surface somewhere else (eg. Mirror/copy the existing horse shoe shape) so the centroid of all of them lies at the center of the arc.
  • disladisla
    edited February 2023
    There has been a lot of discussion about coupling and each one has its own recipes to set it up. And not always work.

    This are some personal advice.

    -Move the model so the REF node occupy the (0,0,0) coordinates (same as the ROT Node) and nothing else there. May seem arbitrary and I can’t rigorously give you a reason for that but ...

    -Coupling with surface on solid elements if possible. If you work with shells, transform the shell to solid just for that specific coupled area.

    -Distributing usually works better with force and moments.
    -Kinematic usually works better with displacements and sometimes force and moments.
    -Rigid Body both.

    -In all cases if you try coupling displacements avoid mixing directions in the same BC.

    -Start slowly and don't push too far as coupling means to artificially overstiff/over constrain. Check solution with various deformation factors to see what's going on.

    Check carefully your results and that solution is compatible with the imposed BC.

    Find attached some examples. I haven't check if results are good.

    Good luck.





  • disladisla
    https://we.tl/t-OdoLP6scR5
  • UGMENTALCASEUGMENTALCASE
    Cheers for the information everyone. I'll take a look
  • JohnMJohnM
    If you need the right answer, put a part in that mimics the feature that is transferring the load. In the example, the collared ring actually comes out of contact and concentrates more load at the extremity. Also be careful with your frictionless support backer. If the part is held at the bolts, and there is even a small amount of clearance behind it, the vertical section of the bracket will take an "S" shape which will likely increase the deflection. See attached figure and a "tech note", very similar to you problem.

  • UGMENTALCASEUGMENTALCASE
    Cheers John really helpful. I would normally put the piece in like you have but I don't have all the information for that piece at the moment so was just getting ahead with some ideas :-)
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