Fluid cavity reference point in import analysis Explicit/Explicit 1

[blazejpop]

I'm encountering some warnings while executing the import analysis and wondering if it's possible to get rid of them.
The first Explicit analysis is the case where some airbag is filled with gas to some specific pressure value. The modelling approach is to use the fluid cavity. In order to conduct such an analysis I need to specify the "cavity point" for this cavity which is enclosed by the airbag walls. I have to create a Reference Point in the Part module and then define the cavity point using the created Reference Point in the Assembly module.

When the second part of the analysis is executed (second Explicit analysis with impact test) I get the warnings which say:
"Node set assembly_airbag-1_airbag-refpt_ is not imported, as none of its nodes belongs to the element sets specified for *import."
and
"1 nodes are missing coordinates. The nodes have been identified in node set WarnNodeMissingCoords."

The node which is indicated here is the specified Reference Point. In the visualization module it is also moved to the new position out of the airbag.

Assembly in the first Explicit analysis:

Results of the first Explicit analysis with cavity point indicated in red:

Results in the second Explicit analysis with cavity point indicated in red:

Does anyone have any idea what happens here?

 

[FEA way]

It’s explained in the "Transferring results from obe Abaqus/Explicit analysis to another" documentation chapter:
- fluid cavity definitions can’t be imported
- reference node of fluid cavity is not imported unless it belongs to another element definition that is imported

 

[blazejpop]

Thank you FEA way for you reply.

Regarding your first bullet: The limitations you're talking about are described only in documentation for Standard/Explicit and Standard/Standard imports. There is nothing about that in Explicit/Explicit case. Did they missed it there?
As to the second bullet: It shouldn't be imported but somehow it imports it and marks it with this "WarnNodeMissingCoords" flag. If not, how did this red point end up in there?

 

[FEA way]

Which version of Abaqus do you use ? I’ve found this information in the documentation for 2020 release.

 

[blazejpop]

It's Abaqus 2019 and, indeed, they wrote it in 2020 version of the documentation. Suppose it's true also for 2019.

There's still a question why it imports this point and marks it as a warning instead of just omitting it.

 

[blazejpop]

Specifying a Reference Point of the fluid cavity in the Assembly module instead of the Part module seems to be a solution for the issue. Employing such approach results in no nodes with missing coordinates.