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Meshing curved plates / conical sections

Hi guys,

 

I am struggling with the following meshing problem. I am trying to mesh a straigth section of a tube to a conical section of tube. However I cannot get the mesh to connect properly. 

 

The model was made using the geometry-surface-cilinder function for the conical section and extruded the straight sections. 

 

To mesh the model I used the following steps:

- Assigned a plate property to the surfaces (mesh control - attributes on surfaces)

- Set the mesh size on all curves (mesh control - size along curve)

- Meshed all surfaces (mesh - geometry - surface)

 

Does anyone have a solution for this meshing problem?

 

Thanks for your help.

Regards,

Marcel

2 REPLIES
Solution
Solution
Accepted by topic author Marcel23
‎04-02-2016 06:38 AM

Re: Meshing curved plates / conical sections

Dear Marcel,

This problem is very easy to mesh, your mesh is not coincident because you have two curves, one belonging to each surface: the key is to have only ONE sheet body, not isolated surfaces. You can use use two methods: either create a NonManifold-Add sheet body, or stitch surfaces. My preferred method is always stitching surfaces, the benefits are multiple: the command will do the job of properly have a consistent normal of all surfaces, all surfaces will have the same normal. But NonManifol-Add command simply add all surfaces as they are, not checking normals, then when later you mesh surfaces with shell elements you could have a problem of lack of consistency in shell normals that could cause problems when plotting stress results in TOP/BOTTOM faces, or when applying a pressure load.

 

In summary, you can do the following:

  • Use command GEOMETRY > SOLID > STITCH. The only inputs required for this command are the surfaces themselves, a stitching tolerance, and whether “mergeable curves” should be cleaned up. The tolerance can be adjusted to facility the closing of gaps between surface edges (the default value is 1e-6, but I suggest to use 1e-4, it depends of the model size). This is a very useful command when reading trimmed surfaces from an IGES file. You can read an IGES file, and then use this command to generate a Parasolid solid from the IGES surfaces. You can then manipulate this solid just like any other solid you would have created in FEMAP
  • The limitation of STITCH command is T-like joints, Parasolid can`t stitch them, then the only method is to use command GEOMETRY > SURFACE > NONMANIFOLD-ADD, but make sure all surfaces have consistent normals, OK?.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Meshing curved plates / conical sections

Dear Blas,

 

Thank you for your reply! Stitching worked greatSmiley Happy

 

Regards,

Marcel