CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   ANSYS Meshing & Geometry (http://www.cfd-online.com/Forums/ansys-meshing/)
-   -   [ICEM] meshing of a journal bearing in ICEM (http://www.cfd-online.com/Forums/ansys-meshing/91803-meshing-journal-bearing-icem.html)

Pac August 23, 2011 06:20

meshing of a journal bearing in ICEM
 
Dear community,

I am trying to mesh a journal bearing which more or less consists of two pipe surfaces with different diameters (61.32mm and 61.205mm) as you see, the resulting gap is only 0.0575mm high. The geometry was developed in DM.

From the many problems I have already encountered, there are two, which I have no idea where they come from and much less how to solve them.

1. When generating a PreMesh, at some points periodic around the geometry, Icem melds the surfaces. That of course divides the gap and leads to an unusable Mesh.

2. The Mesh has a large amount of inverted volumes and smoothing only leads to more inverted volumes.

I used an O-Grid.

If you need more details, please ask me for them.

I would be very glad if somebody told where the problems result from and how to solve them.
Thank you,
Pac

BrolY August 24, 2011 07:32

Did you associate all the edges to the curves?

Post some pictures of your problem, it would help a lot !

Pac August 24, 2011 08:03

2 Attachment(s)
Thank you for your reply!

yes, I associated all edges to the curves, I also tried it with associating the vertices to points I created along the curves, but that would not help either.

Here are two pictures, one of the geometry and one of the defective mesh, the location where the inner and the outer surface merge, occures periodicly around the cylinder, left and right of the oil groove.

Attachment 8926 Attachment 8927

BrolY August 24, 2011 08:08

Can you attach your CAO here ?
I can have a look if you want.

Pac August 24, 2011 11:40

That would be great. But I must admit that I do not know what you mean with "CAO". Which files do you need?

BrolY August 24, 2011 11:43

The *.tin file ! CAO = geometry ;)

Pac August 24, 2011 11:54

1 Attachment(s)
oh, ok :) here it is. Attachment 8937

BrolY August 25, 2011 03:57

Ok I think the issue is the gap between the part "Shaft" and the part "Bear" is very thin. At the same time, your geoemtry is pretty big.
It looks like ICEM has troubles to handle this case. You could try to create a lot of splits and to associate each vertices to a node (and also each curves to each edges) ... It would require a lot of time but some ICEM tools could help to handle that.

Have fun ;)

Pac August 25, 2011 06:14

Thank you very much for your help, I already suspected that the dimensions might be a problem but I hoped that there was a trivial solution to this... I will try what you recommended and create more splits and more associations.

Greetings, pac

stuart23 August 25, 2011 20:59

You could try decreasing all your tolerences. The tolerences might be low enough that ICEM just believes that you wanted one surface instead of two seperate surfaces in some areas.

Also maybe try spliting surface by curvature to generate more lines for ICEM to read off.

Stu

BrolY August 26, 2011 03:19

Stuart, if ICEM believes there is only one surface, you would end with a 2D mesh which is not the purpose of this study I guess ...

Pac August 27, 2011 06:57

First of all, thank you two for your help.

After doing what BrolY recommended, ICEM created me an acceptable mesh. There are still some bad elements, but with a little fine tuning, I think I will get rid of them.

I think what Stuart ment is to decrease the tolerence so that ICEM understands that there are two surfaces instead of (in some regions) one. But since it worked by splitting the surfaces, I think that the tolerence was not the problem.

I now ponder if a struct mesh created with the workbench mesher by sweeping would be a better solution than the unstruct mesh created with ICEM...

qingyue1987 December 12, 2011 07:56

hi,
i think you should try to us ICEM to creat much more block .then doing the association work .


All times are GMT -4. The time now is 19:41.