Contact between two metal blocks

Hello all,

I am using Salome 3.2.2. & Code-Aster 8.3 to model a contact problem between two hexahedron (or rectangular) metal blocks. One is steel and the other aluminum. The lower block (Steel) is fixed (say to the ground) and its opposite (top) face is in contact with the upper aluminum block. The bottom face of the aluminum block is the other contact face. The opposite (and top) face of the aluminum block is subjected to a pressure. I am trying a simple linear static analysis involving contact. I suppose I will have to attach \"soft springs\" to the aluminum block to prevent the stiffness matrix from becoming singular (to prevent the aluminum block from \"floating away\" uncontrollably). I just am not quite sure how to do this in Salome/Code-Aster. Somebody correct me if I am wrong.

Does somebody have a good .comm file for such an analysis?

Later on I would like to do an elasto-plastic analysis, where the aluminum undergoes plastic deformation. But that is for another day, another time. Your help for my first analysis will be appreciated very much.

A rough sketch is shown below:

(pressure)
________
|Aluminum|
=======
| Steel. |
_______
(fixed)

JMB

Sorry, I forgot to mention in my previous email that it is a solid (3D) model using tetrahedral linear elements. My additional questions are:

Can I do this with linear elements or do I need to use quadratic tetrahedral elements.

Can I use Salome's (3.2.2) feature for converting linear to quadratic elements or should I do the conversion in Code-Aster, then translate back to linear for the results file?

There are many things I do not understand, because of my limited knowledge of French, so I would appreciate some careful hand holding.

Thank you
JMB

Hi,

I sent you an email reply, but received an error of the kind \"SPAM BLOCKED\" or something like this. Did you receive my email anyway?

You can find some elements of answer in my reply to Jerry in the Salome Forum: www.caelinux.com/CMS/index.php?option=co...p;id=774&catid=4

and more important, try to have a look to the Advanced Examples / Contact problem.

For the stability concerns, do you absolutely need an imposed pressure or could you live with a imposed displacement?
Imposed displacement is for sure the best option for stability concerns, but is it does not suite your needs, you will need to create some \"springs\". The best way to create
springs in an easy way is to create some thin \"extrusions\" out of your volumes with a very low Young modulus.
If you prefer 1D elements, you will probably need to create \"CABLE\" elements (1D springs with non-linear capabilities).

Concerning the quad/lin question: the best option is to create quadratic elements directly from Salome either by specifying the 1D hypothesis option \"Quadratic elements\" or with the lin2quad conversion tool (check project on geometry, geometriy is very important for contact!!).

Good luck

Hello admin,

Thanks for your advice. I have been able to analyze quite a few models utilizing contact. I am now trying contact with friction. I think a good source of information for this specific topic is SSNV128 (V6.04.128b) available in English as well at \"www.biomechanik.fh-aachen.de\" I intend poring over it to learn more...

JMB