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N.R. July 26, 2007 10:51

define surface in 3D with quadratic elements
 
Hi,

does anybody know how to define a geometry with quadratic triangles? When I import a geometry (e.g. in nastran) made out of quadratic triangles (CTRIA 6 type), the surface will not be interpreted correctly (no smooth triangle sides). However when I import the quadratic triangles as a mesh (same nastran file) they are interpreted correctly (smooth transition between elements).

Is there a way to define a geometry from a mesh in ICEM? Can you recommend an open ascii geometry format for quadratic triangle or quad elements? Can you remesh a quadratic mesh independent of a geometry, keeping the outer described surface?

Thanks,

N.R.

Robin July 26, 2007 11:21

Re: define surface in 3D with quadratic elements
 
Hi N.R.,

You can't do this in ICEM CFD but you can re-create your smooth geometry in the ANSYS Workbench FEModeler module. You can then load the geometry into ICEM CFD or the Workbench Meshing module from the Workbench Project Page.

Regards, Robin

N.R. July 26, 2007 13:04

Re: define surface in 3D with quadratic elements
 
Thank you for the hint! But when I import the CTRIA6 elements via nastran into FEModeler the adjacent nodes are still connected by lines instead of a smooth curve... Although the import statistics show that all of my elements are of type "Quadratic Triangle CTRIA6 Curved Triangular Shell " Am I importing in a wrong way?

I would now like to create a surface geometry which takes into account the smoothed data from the quadratic elements. Which command do I use to export to a geometry? Which format can I use that ICEM supports?

Thanks,

N.R.


Robin July 26, 2007 14:24

Re: define surface in 3D with quadratic elements
 
Hi N.R.,

I don't use this tool much so I'm short on details. You need to create a skin and subsequent geometry. I've done it before and it is relatively straightforward, but I'll refer you to the doc for more details.

Once you have the geometry in FEModeler you can actually do some simple parametric changes to the model such as extending a surface in a specified direction or normal to it's face.

Regards, Robin


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