Contact between plate element and beam element

[Anonymous]

Hello, I am new to nastran FEA.  I am doing a test run on a welded assembly of 2 tubes and a gusset plate.  Forces are simply pulling the ends apart, 10 lb in either direction.  Constraints are: point nearest gusset is fixed, endpoints where the force is applied is constrained to have no rotation and no translation in Y.  The tubes are meshed as beam elements, the gusset is meshed as solid.  I am getting E5000 Singularity detected at grid 4347 component 3.

See images

I am thinking it is probably the contact between the gusset plate and the tubes.  How do I do that?  Is it a surface contact?

[Andrew.Sartorelli · Accepted solution]

Hi Cheyenne19,

Welcome to the Nastran In-CAD. Nastran In-CAD is not capable of generating contact between line elements and shells or solids. Line elements need to be connected to a geometric point on the solid or surface parts. I think a better approach in your simulattion be to use shell elements on a midsurface of the pipes and then join the shells using a bonded contact or offset bonded contact depending on if there is a gap between components or not.

Regards,

Andrew

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[Anonymous]

Thank you.  A followup dumb question: For shell elements, how do I select points to apply forces/constraints? I tried selecting the edge at the end of the tubes, got Nastran could not find a node to apply the load.

[Andrew.Sartorelli]

Hi Cheyenne19,

You can apply a force or constraint to any face, edge, or point in the model. It's important to note that these must geometric entities, adding these things to individual mesh nodes is not available. You may have been selecting a sketch entity instead of a geometric entity and that's why you the load or constraint wasn't being added. If you right-click in the selection field you can select a filter for your selection to only choose faces, edges, or points.

Regards,
Andrew