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I
ilyachaban16-Pearl
16-Pearl
March 1, 2024
Solved

Beam continuity is destroyed by rigid and weighted links

  • March 1, 2024
  • 2 replies
  • 2201 views

Hello, I've been trying to simulate one interesting case in which i did stuck. 
Here is an image of what i've been trying to achieve

ilyachaban_0-1709300647537.png


Here is an example of using advanced rigid link beam is discontinued after first rigid link is applied

ilyachaban_5-1709301150202.png

 

ilyachaban_6-1709301164013.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here is an example of using advanced spring (point to suface(projection)). It is deforming in wrong direction 

ilyachaban_3-1709300972600.png

ilyachaban_4-1709301012301.png

 

ilyachaban_2-1709300913355.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Can you help me solve this mystery?

Best answer by SweetPeasHub

 

The mystery is that nodes on solid elements only have 3 dof and links to them will receive this limitation from them. This means that the selection of rotational dof on the advanced rigid link have no effect. It is also quite easy to create dof conflicts and unconstrained conditions when using links.

 

SweetPeasHub_0-1715171494946.png

 

Add an intermediate rigid link between your original links and the beam that is point to point and the rotational dof are now in effect and can be free. Chaining links like this is not unusual in FEM.

 

SweetPeasHub_1-1715171711980.png

 

 

2 replies

I
ilyachaban16-PearlAuthor
16-Pearl
March 1, 2024

Looks like all models hasn't been uploaded so here it is again

F
fdio-28-Gravel
8-Gravel
May 8, 2024

Do you mean like this?

7c53a2b4-eb80-4cb6-9aa8-62d68040cbfe.png

 

 

 

These is my boundary conditions and I only use sketches, points and no solid model

ilyachaban_0-1709300647537.png

    I
    ilyachaban16-PearlAuthor
    16-Pearl
    May 8, 2024

    yes,exactly how you've shown it.
    but i have to attach beam to solid geometry by some kind of a link

    S
    SweetPeasHub17-PeridotAnswer
    17-Peridot
    May 8, 2024

     

    The mystery is that nodes on solid elements only have 3 dof and links to them will receive this limitation from them. This means that the selection of rotational dof on the advanced rigid link have no effect. It is also quite easy to create dof conflicts and unconstrained conditions when using links.

     

    SweetPeasHub_0-1715171494946.png

     

    Add an intermediate rigid link between your original links and the beam that is point to point and the rotational dof are now in effect and can be free. Chaining links like this is not unusual in FEM.

     

    SweetPeasHub_1-1715171711980.png

     

     

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