Strange BC Issue

Altair Forum User
Altair Forum User
Altair Employee
edited November 2020 in Community Q&A

Hi, 

 

I have a wired BC issue: 

When I run my simulation the BCS/3 'ConstraintFlexion' seems to block my /CLOAD/2 'Torque'. I can see this because their is almost no motion when I compute the simulation, BUT when I delete BCS/3 'ConstraintFlexion' then there is normal motion as it should be. 

However, this makes no sense for me since I defined for both BCs the same skew and applied the Torque to XX and opened the Constraint for R_x. Could someone explain me the reason for this issue?

 

Thanks, Best

Jonas

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Hi Jonas,

    We will check the model and will update soon.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Hi Georg,

     

    Could you figure out the issue?

     

    Thanks,

    J

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Hi J,

    For the BCS/3  free up the translation in Z direction also and try running.

    Along with the rotation there seems some translation dof's also, and so try running with Tz also free.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Hi George, 

     

    Hmm... but I don't want to have translation. If I have a rbody rotation around a fixed point I should not have any translation. What is wrong on my setup that I still have translation?

     

    best, J

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Ah... figured out the issue... ICOG of the rbody was not set to 3. 

     

    Best, J

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2018

    Hi J,

    As a general information, ICoG is the center of gravity computation flag for rigid bodies in RADIOSS.

    If ICoG is kept to 1  RADIOSS solver will automatically calculate the center of gravity and the master node is moved to the computed center of gravity.

    If the user dont want to move the master node keep ICoG=3, so that the master node is not moved.

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