Abaqus coupling constraint entity

Eli Maes_21620

Hi,

 

In the latest release, constraint entities for coupling kinematic/distributing were implemented for Abaqus profile. (the earlier RBE2/RBE3 elements)

Any old RBE2/RBE3s are automatically converted to this new entity when opening from an older version. This new representation makes sense from a graphical and user friendliness standpoint in defining DOFs, properties, etc, but I fail to do some things with them that I used to be able to with the RBE2/RBE3 elements.

• Equivalencing does not take coupling constraints into account. Especially for legacy models, this is quite a big handicap.
• How do I mirror constraints? If not possible, this is a big handicap when wanting to mirror an entire model model. Previously, could just select all elements, mirror, and all RBE2/RBE3s would be mirrored as well, and still be attached to the relevant nodes/elements. Now this is no longer possible.
  • With the new constraint entities, what's the recommended way to mirror a model containing elements/coupling constraints?

Regards,

Eli

Jason_Craanen

Hello,

• Equivalencing does not take coupling constraints into account. Especially for legacy models, this is quite a big handicap.
  • Better option would be to create from scratch using Connectors or Attachments or edit the nodes in the set to be equivalenced.
• How do I mirror constraints? If not possible, this is a big handicap when wanting to mirror an entire model model. Previously, could just select all elements, mirror, and all RBE2/RBE3s would be mirrored as well, and still be attached to the relevant nodes/elements. Now this is no longer possible.
  • Same as above. 

You can very quickly find holes and create attachments. Please check out video below

https://www.youtube.com/watch?v=jjQlDPpLtLY&list=PLGNemB0NFb0C_SyFVrdD9d0WZEr1aUiP3&index=2

Eli Maes_21620

Jason,

 

Because of removal of below functionalities, is there any possibility to offer an option to the user whether they want to use constraints or elements for couplings? (if no feasible, user friendly workaround can be provided that is)

 

The connectors/attachments indeed work fine in theory for a number of cases. However, how do I do the following cases with the attachments?

• A shaft for which I want the OD connected to a node. Somewhere, I'd also need to specify the width of the outer surface/asymmetry relative to the center node.
• Cases where there is no simple center to circumference. E.g connecting random geometry to a constraint.

If there are cases where connectors/attachments cannot be used, then the removal of couplings as elements is a major handicap. In particular for cases where many couplings are present. Lack of ability to mirror in such cases is one of many examples.

 

A number of different usecases where I don't see how connectors provide a solution:

• After the creation of couplings, how do I check if everything is properly attached to my model? 
  • Couplings are no longer recognized by the 'attached' functionality'

 

• Duplicate couplings
  • How do I check if there are duplicate couplings? Previously, could be done by equivalencing and then using duplicate element option.

 

• How do I organize the couplings? If I have a model with couple of 100 couplings, it can be challenging to organize and locate everything through the GUI
  • Previously, with elements, they could be organized within components (or element sets, since components are soon obselete)
  • The connector browser doesn't seem to offer any possibilities for organization/grouping?

 

• How can I select couplings for *model change?
  • Since it's no longer an element, I can't select it anymore

 

• How can I keep an overview of my surface_node set segments in the tree if there are 100s of Set_1, set_2 polluting it?

 

Regards,

Eli

 

Jason_Craanen

Eli Maes_21620 said:

Jason,

 

Because of removal of below functionalities, is there any possibility to offer an option to the user whether they want to use constraints or elements for couplings? (if no feasible, user friendly workaround can be provided that is)

 

The connectors/attachments indeed work fine in theory for a number of cases. However, how do I do the following cases with the attachments?

• A shaft for which I want the OD connected to a node. Somewhere, I'd also need to specify the width of the outer surface/asymmetry relative to the center node.
• Cases where there is no simple center to circumference. E.g connecting random geometry to a constraint.

If there are cases where connectors/attachments cannot be used, then the removal of couplings as elements is a major handicap. In particular for cases where many couplings are present. Lack of ability to mirror in such cases is one of many examples.

 

A number of different usecases where I don't see how connectors provide a solution:

• After the creation of couplings, how do I check if everything is properly attached to my model? 
  • Couplings are no longer recognized by the 'attached' functionality'

 

• Duplicate couplings
  • How do I check if there are duplicate couplings? Previously, could be done by equivalencing and then using duplicate element option.

 

• How do I organize the couplings? If I have a model with couple of 100 couplings, it can be challenging to organize and locate everything through the GUI
  • Previously, with elements, they could be organized within components (or element sets, since components are soon obselete)
  • The connector browser doesn't seem to offer any possibilities for organization/grouping?

 

• How can I select couplings for *model change?
  • Since it's no longer an element, I can't select it anymore

 

• How can I keep an overview of my surface_node set segments in the tree if there are 100s of Set_1, set_2 polluting it?

 

Regards,

Eli

 

Hi Eli,

All these concerns are covered in upcoming release. 

For now KINCOUPs are created as elements. COUP_KINs have migrated to constraints.