Issue with Skew

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

Hi, 

 

I try to define a moment around a local axis. I created a skew using 1D>systems>create by node reference. That worked! However, when I select it in the BC Manager 'Select skew' it is not assigned. Is this a bug or what am I doing wrong? (see attached file)

 

Thanks, J

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Hi,

    From the skew option, select the select skew option and pick the created local system.

    In the skew variable option you can see that it has been updated.

    <?xml version="1.0" encoding="UTF-8"?>Capture.PNG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    It looks like this on the first moment. But when you look how the moment is applied you can see that it is not assigned and still aligns to the global system (). Also when you change the ID nr from 1 to 2 it stays on 1 in the BC-table. 

     

     

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  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Hi,

    In the model file you have shared the id of the local system created is 1 and the same is assigned to BC which is shown in the above image.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Yes, and I changed it to 2 now and it stays 1 in the other file (even after updating). And it is also obvious (see image from post before) that the moment is aligned to the global system and not to the local one. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    When I create a second system and assign it to the moment the ID gets updated. So that seems to works. But nevertheless, the arrow shown by the software (CLOAD_M = 1.00e+000) still stays aligned to the global coord. system! ---> 

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  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Hi,

    Once the skew is updated in the load collector you can continue. The load direction will be with respect to the skew defined.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Hi George, 

    I know what you mean and how it is supposed to work. But in my model it is not like this. I assign the skew, I update and it will always stay oriented to the global system. Please try it out yourself with the model file I uploaded. Please also look at the screenshots I provided (which are taken after updating). It is clearly seen that the moment is orientated to the global system and not to the local. 

    I tried it out many times with different skews, with recreating the moment, with changing the order of defining everything, ect. Still the moment as visualized by the software keeps oriented to the global system! 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2017

    Hi,

    I just reviewed your model. And it seems to be fine. The CLOAD is acting as per the local skew defined, that is in  the XX  of the local skew.

    If you still have issues, please share the final model (_0000.rad) and the .h3d files.

    <?xml version="1.0" encoding="UTF-8"?>Capture.PNG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2017

    Hi George! 

     

    Thanks a lot! Your right it's only a visualization issue. I tried it out with a simpler model and experienced the same issue (as described above) but when I run the simulation it acts correctly according to the skew defined in the BC-Manager. But maybe something that should be corrected to prevent confusion! 

     

    Thanks anyway! 

    Best, J