Meshing error where multiple members of a beam frame meet

Gotta_Go_FastGotta_Go_Fast Member Posts: 2
edited October 2020 in Structural Mechanics

Hello everyone,

I am performing a static stress model on a chassis and I have encountered an error where the solver reports I have unconstrained nodes. I am certain I have the correct constraints.

My process for preparing the frame went like this:

  1. Import Parasolid from Solidworks
  2. Extra beams in SpaceClaim
  3. Fix gaps <= 25mm
  4. Manually trim some erroneous edges
  5. Imprinted areas where possible

I then imported my beam frame into ANSYS Mechanical with a static structural model. Then I meshed the frame and applied some boundary conditions. To simulate a simple front impact, I selected nodes at the back of chassis to be "simply supported." I persistently get solver errors due to different nodes having degrees of freedom. I have also changed where the constraints are just to make sure I did not make an incorrect assumption; the zero pivots persist regardless.

I checked the 0Hz frequency in Modal and found an element floating in and out of a joint. Very strange!

The geometry where the frame members meet looks messy. I am a novice so I do not know the correct way to "clean up" this geometry. I think these joints are the ones causing unconstrained errors.

I sincerely appreciate any help, I've been stumped for many many hours on figuring this out!

Thanks so much!

Best Answer

  • gnagappgnagapp Posts: 204Forum Coordinator
    Accepted Answer

    In Spaceclaim, display the beams that should be connected at these intersections, go to Workbench tab and click on Share. Click on the check mark to connect these beams. This will ensure that the beams are connected with each other at the intersections in Mechanical


    (Another option is to use "node merge" in Mechanica instead of this share in spaceclaim to make sure the beams are connected)

    In Mechanical, turn off thick shells/beams display and check the mesh

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