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# Hex mesh T tube joints

Creator

Hello everyone,

Does anyone know how to properly hex mesh a T tube joint in FEMAP?

I have tried several approaches, deviding the surfaces, extruding, etc. See the attached image for example.

A general approach for T tube joints of same diameter would be nice, if possible.

9 REPLIES 9

# Re: Hex mesh T tube joints

Solution Partner Phenom

Dear Igor,

Is very easy, for instance a T-Join tube of external diameter Ø220 mm and thickness 10 mm:

Simply split solid (use command GEOMETRY > SOLID > SLICE) using symmetry planes. Also use the length of the external arc to split the horizontal tube by plane X-Y. Next use the resulting distance "A" to split the vertical tube by plane X-Z. Also split the solid by the intersection plane of the two tubes, and you are done!.

Next use an element size to have 3 elements in the thickness or so, you will need to "tune" the number of elements to have a regular "mapped" mesh, play with number of divisions using the MESHING TOOLBOX to have the same number of elements at opposite curves, here you are mine:

And finally mesh the geometry using HEX elements, the resulting mesh will have the following element quality:

```Check Element Quality
32655 Element(s) Selected...
No Elements Outside of Maximum Allowable Value.

Quality Check               Number Failed      Worst Value
Hex AR                             0           3.345548
Hex DetJ                           0           3.713188
Hex Warp                           0           0.999913

0 Elements Failed out of 32655 Checked.```

Try yourself and enjoy!.

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/
Highlighted

# Re: Hex mesh T tube joints

Creator

Hi Blas,

Sorry, i think i did not make my question very clear, i intend to mesh the full volume for a CFD simulation.

The volume inside a tube.

# Re: Hex mesh T tube joints

Siemens Phenom

Try using the command Geometry > Solid > Fill Hole and select one of the inner diameter arcs of the tube.
You can then use the method that Blas has shown to slice the solid and hex mesh the part.

Before:

After (hiding the original solid):

# Re: Hex mesh T tube joints

Creator

Let me explain my problem a little further.

Here is all of my geometry:

Here are some of the joints, that are giving me trouble.

This is an "OK" mesh for CFD:

The ideal would be to have the mesh that i plan to extrude all over the model, but i dont know if that will be possible due to the joints, so basically i am trying to hex mesh the volume including the joints.

This is just to elaborate further my problem in case anybody else looks at this post.

Thank you both for your sugestions, i am going to try that right now. If it works i will post the result here.

Att

Igor

# Re: Hex mesh T tube joints

Creator

Hello everyone,

It has worked when i followed @Blas_Molero's method.

@Blas_Molero thank you very much, i have a couple more question if you dont mind.

1- How do i plot the element quality like you did?

2- Do you think its possible to make a mesh like this :

Throughout the joints using the method you just posted? I'm going to try that now.

Thanks.

@T_Giampietro thank you very much too.

Att

Igor

# Re: Hex mesh T tube joints

Siemens Phenom

To plot element quality click the Contour Model Data button on the toolbar.

In the dialog box check "Show Model Data Contour" and expand Element Quality to select the criteria you would like to show.

# Re: Hex mesh T tube joints

Solution Partner Phenom

Dear Igor,

Well, I can do it, but takes time, is not immediate, with multiple joints at different orientation many solid splitting are required, and to arrive to a consistent HEX mesh with multi-solid sizing at the same time is complex, not doubt. Hopefully FEMAP in the future can make it at the push of a button?, we will see!

2- Do you think its possible to make a mesh like this :

Throughout the joints using the method you just posted?

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: Hex mesh T tube joints

Creator
Many thanks, it worked

# Re: Hex mesh T tube joints

Creator
I see, i tried it for sometime and got some results but it is very time consuming. I hope too some improvements are made on hex meshing, it is crucial specially for CFD...
Anyway, thanks for the help

Att