Troubleshooting seam-quad LTB Connector

Fellow community user @Mandy Kramer sent a HyperWorks forum question seeking guidance on how to identify and correct realization troubles for seam-quad LTB connectors. With their permission, I put this Knowledge Article together with a few best practices. Hope this is useful!

This article includes:

The Models and Presentation can be downloaded here.

The model contains six connections, as numbered below:


Connector 1: T-Joint

Question: How to change this from a continuous to an intermittent/stitch weld?

Answer: From 2022.3 release onwards, skip welding is available as a parameter for all line connector controls. For versions before 2022.3, there are two workarounds:

  1. You’d need to manually define separate connectors or
  2. Delete the connector and the elements which are supposed to be skipped. (Downside is that you lose the connector);

Connector 2: B-Joint

Question: The surfaces are coplanar and I've tried a range of connector tolerances, but the "Incomplete realization" error persists.

Answer: This connector only has one link. When creating the connector, make sure at least two components are inside the tolerance. After connector creation, even if you change tolerance, it won’t be able to realize because it doesn’t know who it’s supposed to connect (links). You can right click the blank space of Link 2 -> Add. Then try to realize it 

Connector 4: L-Joint

Question: How do I switch the direction of the angled shell element row? It's pointing inward toward the lap seam by default.

Answer: Try unrealizing then realizing it back again. If it doesn’t work, you can swap the Angle Direction, under Behavior

Connector 5: T-Joint, with overhanging nodes

Question: T-connection with some overhang. I am unable to get this to realize alone or along with the other connectors.

Answer: Trim the connector so it “sees” both links at all projection points. Double click it, then choose Trim. Click somewhere along the connector that you know it won’t overhang. This will divide the connector into two. Delete the overhanging one.

Connector 6: T-Joint at an angle

Question: Generated elements but is displaying a "quad transition error." Can you give guidance on how to address? Do you have any tips for working through the transitions for the corners where 3 or more weld seams are coming together?

Answer: Quad transition error doesn’t necessarily mean the connection wasn’t realized. Maybe the remeshing step couldn’t be completed. This is a sensitive case because there are 3 connectors intersecting. I suggest breaking connectors into pairs of components. Current configuration:

Best configuration: Trim Connector ID 1 so you end up with 2 separate connectors (7 and 8), with following links:

The end result should look like this:

Best regards,
Paulo Libório.