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Problem with a seam weld in V.Lab Durability

Experimenter
Experimenter

Dear Sirs,

I can't generate a seam weld. The weld status is "additional elements connected to seam welds".

The weld is defined bewteen two rows of shell elements connected by another row of shell elements. Automatic search was chosen.

Would you mind helping me?

Thank you very much

 

Best regards

Riccardo Testi
---
Development and Strategies
2 Wheeler Engines Technical Centre
Piaggio & C. S.p.A
Viale Rinaldo Piaggio, 25
56025 Pontedera (Pisa) - ITALY
Phone: +39 0587 272850
Fax: +39 0587 272010
Mobile: +39 339 7241918
E-mail: riccardo.testi@piaggio.com

6 REPLIES

Re: Problem with a seam weld in V.Lab Durability

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor

Riccardo,

 

Listed below are the mesh techniques supported by LMS Virtula.Lab Durability Seam Weld analysis. Please confirm your model matches one of these configurations.

 

Mesh Techniques Supported by LMS Virtual.Lab for Seam Weld Definition2.pngRegards,

Paul

 

Re: Problem with a seam weld in V.Lab Durability

Experimenter
Experimenter

Paul,

please find attached a description of the attempts I made.

Thank you very much

 

Riccardo

Re: Problem with a seam weld in V.Lab Durability

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor

Hi Ricardo,

The example shows a configuration that is not supported for what you are trying to do. I understand that you wish to model a tube section welded to a flat plate. Here is the modeling that is supported:

 

Option1:

1. Replace the shell elements connecting the tube (pink color) to plate (yellow color) with MPCs (RBE3 for example).

2. Put the Tube element into group1. Put the Plate element in group2.

3. Select group1 for Base Sheet, select group2 for Weld sheet

 

The detection should find the weld at the MPC connection.

 

Option 2:

1. Remove the shell elements connecting the tube to the plate.

2. Make common nodes in the tube and plate that defines the weld line

3. Put the Tube element into group1. Put the Plate element in group2.

4. Select group1 for Base Sheet, select group2 for Weld sheet

 

The detection should find the weld at the MPC connection.

 

If there is really a sheet connecting the Tube to the Plate then the alternative is:

1. Put the Tube element into group1. Put the Plate element in group2. Put the the Connector elements (green color) in group3

2. Select all groups for weld detection.

 

The detection should find 2 T-welds; 1 at the Plate-Connector and 1 at the Tube-Connector. This assume there are common nodes between the Plate and Connector, and the Tube and Connector.

 

I assume this is really not your situation but I thought I would mention it.

 

Good luck!

Paul

Re: Problem with a seam weld in V.Lab Durability

Experimenter
Experimenter

Paul,

unfortunately V.Lab does not recognize MPCs connections coming from Ansys, which is the FEA tool I use; so Option 1 cannot be followed.

I will try Option 2, even if it will be painful, since the real structure is a scooter frame, whose shell model comes from midsurface extractions of many 3D CAD parts; that's why gaps exist between the shells.

Thank you very much

 

Regards

Riccardo

Re: Problem with a seam weld in V.Lab Durability

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor

Hi Riccardo,

 

The VL Help Docs says REB3 elements are supported.

 

On a side note, I asked a colleague about this example. He stated that the I-Weld does not have a background fine model and therefore the Force Based approach does not work. This is a known limitation for this type of joint. Also the model with the connector sheet is appropriate for I-weld. (I did not know this!).

 

For I-weld it is recommended to use the Stress Based approach where you will have to pick a S-N curve from the IIW library. In this case your first weld selection method is correct. Just use the Stress Based tab below on the Edit Seam Weld dialog.

Re: Problem with a seam weld in V.Lab Durability

Experimenter
Experimenter

Paul,

thank you very much again. I'll switch to the stress-based apporach.

 

Best regards

Riccardo