how to assign property to RBE and rigid elements

Altair Forum User

Hi,

 

Are RBE and rigid zero dimensional elements? If they have zero dimension, is it right that I dont need to assign any property into them when mesh is generated for weld?

Please see the attachment for weld area.

 

Many thanks

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Altair Forum User

Hi,

 

you are right, you don't need any property for RBE3/RBE2.

 

I suggest to use RBE2 elements for your type of connection (since it is a rigid element and typically for weldings as you are using)!

 

Regards,

Mario

Altair Forum User

Hi Mario,

 

Tnaks for your suggestion. I just tried and it works perfect. 

But, as far as I can see from the model, there arent any difference between RBE2 and RBE3. Can you please indicate the difference between them?

 

Many thanks.

Altair Forum User

Hi Thomas,

 

The both element types are more or less complete different.

 

 

RBE2 – Rigid Body Element

Defines a rigid body whose independent degrees-of-freedom are specified at a single grid point and whose dependent degrees-of-freedom are specified at an arbitrary number of grid points.

 

RBE3 – Interpolation Constraint Element

Defines the motion at a 'reference' grid point as the weighted average of the motions at a set of other grid points.

 

 

RBE2 are transfering displacements/rotations and are complete rigid.

RBE3 are transfering forces and moments and are not rigid.

 

I don't want to write more then this here, but feel free to look at the manuals and internet for more informations.

 

Regards,

Mario

Altair Forum User

Hi Mario,

 

Thank you for the clear explanation of definition and function of both elements.

 

 

Regards,

Thomas

Altair Forum User

Hi, 

 

Although this topic is called 'how to assign property to rbe and rigid elements', what I would like to know is the opposite: how to remove an assignation I seem to have done to some RBE3 without being aware of it. I realized I had made a mistake when i showed the model by property, and also by material, and these elements didn't appear in grey colour. 

 

Thank you for your help,

 

Julio

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Simon Križnik

Hi,

 

if material and property were assigned indirectly (on component) just create new component and move RBE3 elements with Organize panel (shift+F11).

If material and property were assigned directly (by right-clicking property then assigning elements) go to toolbar button Property Collectors panel>assign>unassign.