Need help in meshing a simple plate

Sorry Johannes that I've created confusion with my words.

I should have said:

I enter "Face_1" into the "Main Shape" entry space in the dialog box.

I do not have an Add button available to add edges -- it is grayed out.

If I try to click on one of the edges in the left window, it makes no difference. The Add button is still grayed out on the Group dialog box.

If I click on Select All (the only button that is not grayed out), then I get 4 numbers in the dialog entry box and the Add and Remove buttons become available (not gray).

However, though I seem to be able to remove entries, I cannot actually add them.

Here is what happens: if I try to click on an edge in the left window, the Add button becomes gray again. I cannot click it.

If instead of Face_1 in the "Main Shape" entry box, I instead try Edge_1, I can only add that by clicking Select All. I cannot add any other edges, since that is now the "Main Group".

Thank you again for your help.

Best Regards,

Steve

Well, I've tried a workaround of Selecting All and then deleting the edges I don't want. The reason I hadn't tried that before was that I couldn't tell what I was deleting. There were simply the numbers 3,6,8, and 10 in the small window in the dialog box.

However, if I clicked on each of the numbers, the 3D display window would highlight the edge that the number corresponded to. So I finally deleted all but edge 3.

Of course it would be important to understand why the "Add" button doesn't work, especially because on a complex model it would be very difficult to do things the other way.

But I did want to try to solve this particular test problem. So I created my face and edge groups the hard way, computed the mesh, and wrote it out to a med file.

Then I tried to start ASTK. It wouldn't open, but instead threw an error message. Because this problem is a separate topic, I will open it in the Aster Forum section.

Meanwhile, I'd still like to understand why the Add button doesn't appear for me.

I did go to the Salome website, and found that there was a version 4.1.4. Service Pack 2 , and even a version 4.1.5. I wonder if what I am experiencing is a bug that was later corrected.

Thank you Kees! That makes me feel a lot better..... though I'm sorry you to have a similar problem. At least now I know it is a bug in the software, rather than a problem with my computer.

Too late to report the bug, I guess in version 4.1.4 -- it sounds like Salome has moved on.

Is there a way of telling what the object number is without selecting the object in the 3D screen, or the New Group dialog box?

I thought maybe it would be in the object explorer under "Entry" or "Reference Entry" but they are different numbers. For instance I see the numbers 3, 6, 8, and 10 in the Group entry box after hitting "Select All"

But under the "Entry" column in the explorer I don't see anything with a "10" in it.

Thanks again for your help. Also, you're welcome for the small word correction -- even though it is a wikki, I didn't want to change anything listed under someone else's name.

Best Regards,

Steve<br /><br />Post edited by: Steve Rednond, at: 2009/10/19 22:20

Addressing the basic request for a simple shell model mesh ... I would try something like proposed by Dr. Ackva. In SALOMÉ go to the GEOMETRY module. Define the four corner points, connect them with edges and define a face from the edges.

Then go to the MESH module. Create a new mesh on the geometric face - netgen 1d-2d mesh of linear triangular elements. Calculate the mesh. Then create groups of elements and nodes. The element group PLATE will identify the elements belonging to the geometric plane and the node group EDGES will identify the nodes belonging to the edges which you will support. If you change the mesh and recalculate, beware to redefine these groups.

When satisfied with the mesh: right click the mesh and export it to a file in MED.

You can now continue to the ASTER module with the following three informations for the analysis:

1. The mesh file
2. The group name for the elements
3. The group name for the nodes to be constrained.

Everything else will be in the writing of the ASTER command file. Only thing I have assumed is that you will use linear triangular elements (e.g. modélisation DKT) which will be good for small deflections. I have no experience with eigenvalues in ASTER but I guess that previous posters have enlightened that topic.

I have written the module names in bold typeface in order to emphasize that definition of groups of elements and nodes take place in the MESH module, not in the GEOMETRY module and the reason I do that is that it seems to me that you are following a different approach by defining groups while still in the GEOMETRY module.

Good luck with the analysis, and when completed it will be interesting to see the results.<br /><br />Post edited by: Torben, at: 2009/11/18 12:22