Error with CBEAM's for lattice based geometry

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

Hi, 

 

I am attempting to create a lattice structure using CBEAM's. I have created a box geometry and filled it with CBEAM's. This was achieved by solid map meshing, then using the mesh to create CBEAM's. However, I have now applied some BC's and when I run my model I get the message:  

 

*** ERROR # 1203 *** in the input data:
 Vector defined in fields 6 - 8 has zero length.

 

I believe that this has something due to the orientation of by CBEAM's but because I have so many CBEAM's I'm not sure how I would correct the orientation or what to correct the orientation to.

 

I have attached my *.fem file. If someone could have a look I would be very grateful.

 

Laurence

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited March 2019

    Hi,

     

    in the shared model no property and material were assigned. Material parameters were not defined so I have set up generic steel properties. I have also set up solid property for lvl0 component. Use Tools>Model Checker>Optistruct to find modeling errors.

    https://insider.altairhyperworks.com/wp-content/uploads/2017/09/T-T-1248-HyperMesh-Model-Checker.pdf


     

    Use the 1D>bars>update panel to update orientation (local axis). The element orientation is critical especially for noncircular, un-symmetric, or irregular sections. Orientations aligned with the beam axis are not allowed. The following document & videos might give you an idea about 1D element orientation and why it is important:

    https://altairuniversity.com/wp-content/uploads/2017/03/1D_Elements_Extract.pdf



     

     

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  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2019

    Hi Ivan,

     

    Thanks for the very thorough reply! I now understand that the orientation is wrong, and it needs to be along the axis vector. Is there a way to change the orientation of all elements that fail in one go, rather than individually? How did you do it?

     

    Kind Regards,

     

    Laurence Maskell

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited March 2019

    Glad to help. 

     

    If you are not interested in “location” of the stress recovery points you can define orientation in one go with 1D>bars>update>orientation>components and enter 1 for each x,y and z components and update local axis. If there are some elements aligned in this diagonal direction still causing error 41, slightly adjust the value in any direction.