direction of celas1 elements

Altair Forum User

hi,

if we connect two element with celas 1 elements and allowing dof3 will that allow movement in global z direction or z- direction of that element??and can u pls tell me directions of dofs?

Altair Forum User

Hi Jahnavi,

 

Can you explain what do you mean by allowing Dof3 for CELAS element?

 

When creating CEALS element the Dof defines the stiffness direction. 

tinh

Altair Forum User said:

hi,

if we connect two element with celas 1 elements and allowing dof3 will that allow movement in global z direction or z- direction of that element??and can u pls tell me directions of dofs?

 

I think you haven't understand my explanation yet

In you case, direction is global z (blue z, if 2 celas nodes are not assigned to any other system)

'allow movement' is not correct,

Instead of that, celas provide stiffness and movement along that direction is affected by the stiffness value

 

Altair Forum User

hi,

thankyou. but my problem is i want to allow only vertical vibrations in my system. so i chose dof3 so that it would provide  stiffness in z- direction only, but while connecting celas elements some of the celas  elements are  connected laterally  i.e length is along y direction with dof 3 . then it instead of vibrations in global z- direction it is moving in the z- direction of that element.how should i connect celas elements so on the whole the vibrations should be in vertical direction only??in which direction will i have the vibrations if connect celas elements as in the figure?

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

Altair Forum User

@jahnavi

 

How many such elements do you have?

 

You can try with CBUSH element by assigning a local system.

Altair Forum User

i'm using around 200 celas elements?? how can i assign local system to cbush elements??

Altair Forum User

@jahnavi

 

FYI,

 

 

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

Altair Forum User

can u pls tell me that if  i give z- axis in the system in which direction the movement of cbush element be??

Altair Forum User

Jahnavi,

 

You can provide stiffness via PBUSH property. So if you provide stiffness in only Zdirection, then the BUSH element will behave as a stiff element in Zdirection compared to other directional components.

tinh

Altair Forum User said:

i'm using around 200 celas elements?? how can i assign local system to cbush elements??

 

 

Look like you need a script 

ex: (will create a system for each celas, and assign 2 nodes of celas to that system)

 proc p_AssignCelasSystem {} {     *createmarkpanel elems 1 'Select Celas elems:'     set ElemList [hm_getmark elems 1]     foreach ElemId $ElemList {         lassign [hm_nodelist $ElemId] Node1 Node2         set Vector [list [expr rand()] [expr rand()] [expr rand()]]         *createmark nodes 1 $Node1         *duplicatemark nodes 1         eval *createvector 1 $Vector         *translatemark nodes 1 1 1.0         *createmark nodes 1 $Node1         *systemcreate 1 0 $Node1 'z-axis' $Node2 'yz plane    ' [hm_latestentityid nodes]         *createmark nodes 2 $Node1 $Node2         *systemsetanalysis nodes 2 [hm_latestentityid systs]     }     *nodecleartempmark; *clearmark all 1; *clearmarkall 2 }