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LFM1995

Error with CBEAM's for lattice based geometry

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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

Lattice_trial.fem

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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

 

 

lattice_trial_edit.fem

LFM1995 likes this

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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

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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.

 

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