Dear Enrique,
Thanks very much for your nice help!
I really want to know in the sample, when the air is meshed with unstructured elements, and the length and width are meshed with 40 interval while the thickness with 4 interval. But I can’t generate it.
If the lenth and width are meshed with 200 interval, the problem will be very large for the Finite element analysis.
My problem is more complicated than the sample I attached.
Here the attachment is my problem. And in this attachment model(team13all.geo),I enlarged the air gap from 0.0005 to 0.0032 compare to the real model(which is also in the attachment,PDF file,and team13last.geo). if I didn’t enlarge it ,I can’t generate the mesh. (Or I can generate the mesh all with unstructured elements, but air gap is only with one element.I want split the air gap for 3 or 4 interval.)
My ideal was that after I generate the mesh, I would modify the coordinate of the node in the air gap to the real model.
So after this idear, I enlarge the air gap and the thick of steel,too. ( team_13_OK).But the problem is after I
modify the coordinate, there are some elements(6,7) are bad( their volume is little than 0).
So the core problem is that I don’t want to modify the real model, and I want to spit the air gap and the thickness of steel to 3or4 intervals. Because the air gap is very important for the FEM result. And I used this mesh, my result is 1/3 of the experiment result.
I work on the model for 2 months, and there is rare progress. So I’m so appreciate for your help and suggestion.
By the way, our group bought 6 license of GID8.0.2. how can we update to GID9? If GID9 will be help in my problem?
Best regards,
CHEN Ningning
I have been able to generate a mesh without any problem using GiD 9.1.0b
Rfast, Automatic correct sizes=Normal, transition=0.7
internal volume structured 200x200x4 cells (your applied number of
divisions)
General mesh size=0.1
I’ve obtained about 1.6 Milion of elements
The geometry is very simple, if you are unable to mesh unstructured with the
number of divisions that you want, then you can split your volumes into 27
structured volumes (it’s easy to rebuid it using the copy window)
I attach this kind of splitted model, you can generate the mesh with the
current number of assigned divissions to obtain 9.36 Milion of hexahedra (or
assign less division to avoid so big mesh)
Enrique
----- Original Message -----
From: “CHEN Ningning” xjtucnn at 163.com
To: gidlist at gid.cimne.upc.edu
Sent: Thursday, February 19, 2009 6:18 AM
Subject: [GiDlist] Hi,there is a question about the unstructured mesh on
thin plate
Dear gidlist，！
There is a question about the unstructured mesh.
When I model a thin plate surrounded by air in 3D(the long and width are
100 times than the thickness), I want to using unstructured tetrahedral
elements to mesh the air.
The problem is I want to mesh 4,5 intervals on the thickness direction to
assure the accuracy of the solution, so I need to using structured mesh on
the thin plate.
But when I generate the unstructured mesh on the air, I failed.
I must guarantee the size of edge on the triangle element on the
intersaction of air and plate is almost the same. Just like if I mesh 4,5
intervals on the thickness direction, I must mesh 400-500 intervals on the
direction of the longth or width.
I want to only mesh 40,50 intervals on the direction of the longth or
width, but I can’t generate that mesh.
Are there any parameters which allow me to generate the mesh?
I have set the unstructure size transitions to any value I can, but it
failed also.
My major is computational electromagnetics and there are many problems about
very thick air gap in between the iron.
So it is the problem disturbed me most.
The attachment is my model. Thanks,
Best Regards，
_ CHEN Ningning_
_ 2009-02-19_
Best Regards，
CHEN Ningning
2009-02-20
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