Formula Student Chassis Analysis

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

Hi,

 

I've followed one of the video tutorials to perform a torsional analysis on our chassis, however, there is a problem, which I am not sure how to fix.

 

Basically, a few components of the chassis seem not to be connected to anything therefore the whole structure loses stiffness and analysis obviously is not correct.

 

When I run the check for free 1D elements it shows 16 free 1D elements and this must be the problem. I've tried using the function to connect the nodes (equivalence), but it didn't help.

 

I attach pictures, first on is showing free elements and the second shows that the elements act as if they are no connected (eg main roll hoop).

 

Could someone help me of how to fix this problem?

 

Thanks,

 

Justas.

<?xml version="1.0" encoding="UTF-8"?>post-33784-0-62119600-1424722324_thumb.j

<?xml version="1.0" encoding="UTF-8"?>post-33784-0-48368700-1424722331_thumb.j

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2015

    Hi Justas,

     

    one of the reasons why HM could not equivalence the nodes is because there is no node available within the tolerance limit.

     

    One suggestion is that split the 1D elements and equivalence or use replace panel (F3 is the shortcut) to attach the free node to the nearest node manually.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2015

    Thanks for you help Prakash,

     

    The nodes replacement did work for a few of the free nodes and main roll hoop finally shows deformation, however for a few other ones I get the message 'Replacing nodes would destroy the element', which makes sense, but I'm not sure how do I go about solving this problem? 

     

    Also, if I try to use equivalence function, the tolerance has to be very big for it to work and it would distort the structure.

     

    For example, what would be the best way to attach these 3 free elements to the structure in the picture below?

    <?xml version="1.0" encoding="UTF-8"?>post-33784-0-62198300-1424774835_thumb.j

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2015

    Hi Justas,

     

    yes, with high tolerance there is a chance of distorted element(s).

     

    Assuming you have few free 1D elements,

     

    one way is to split the elements. Use Split panel (F6 is the shortcut) to split the 1D elements (NOT THE FREE 1D elements) such a way that a node is created near to the free node of the 1D element.

     

    or

     

    Delete the free 1D elements and recreate using bars/beams panel in 1D page.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2015

    Thanks a lot!

     

    Splitting elements and then equivalencing worked great.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2015

    Thanks for the update image/emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'>

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