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Ansys Basic Structure random Force/Deformation

  1. Feb 10, 2012 #1
    Ok I've been surfing trough the internet for quite some time now trying to find a solution to my problem but nothing similair pops up.

    This is my problem:

    http://i40.tinypic.com/295dc9f.png

    For some peculiar reason the structure tends to bend over to the left. I have no idea why and i've tried to change te thickness and strength of the center Link/2d Spar without any luck.
    The results show a force acting in the x direction in the top and bottom as if some kind of torque is applied..

    When I remove the center piece the results do not include the erroneous force/deformation and it just streches while keeping the horizontal bar absolutely horizontal.

    Does anybody know why this deformation is not symmetric ?
     
    Last edited by a moderator: Feb 12, 2012
  2. jcsd
  3. Feb 11, 2012 #2

    nvn

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    Science Advisor
    Homework Helper

    Po1ng: Yes, it appears your structure is unstable; therefore, the structural analysis solution is ill-conditioned. Therefore, the slightest numerical inaccuracy (random round-off error) might cause the structure to rotate to one side or the other, randomly.

    Add a horizontal constraint (Tx) at the top joint in your structure, where your applied load is applied, to prevent your structure from rotating about the bottom joint in your structure (where your Tx and Ty translational constraints are currently located).

    By the way, please do not post wide images directly to the forum page. If your image is wider than 640 px (pixels), just post a plain text link to the image.
     
  4. Feb 13, 2012 #3
    Thank you very much! It totally makes sence now that you've explained it. You've just made my day nvn! Now I can finally continue with learning Ansys.

    Sorry about the awfully wide pic.
     
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