[Gmsh] Material non-linearity simulation help

DILASSER Guillaume Guillaume.DILASSER at cea.fr
Tue Jun 28 09:25:02 CEST 2016

Dear Sandeep,

Yes, I my opinion you should be able to simulate a compression test of any kind of material, even a non-linear one, but for this you will not only need Gmsh but also GetDP. Indeed, Gmsh is only a pre/post-processor and you will need a numerical solver to work in tandem with it. To make things easier, you could choose to use GetDP as it is developed by the same people as Gmsh and the two software interact therefore very well. Note however that it is not the only solver you can use with Gmsh and it is maybe not the best to handle mechanical problems. Cast3M could also be a valid choice if you want to have a free solver (the academic & research license is free).

If you want to use GetDP, I would suggest you to have a look on this user-contributed example<https://onelab.info/trac/getdp/wiki/LinearElasticity> (use “getdp” for both the username and password if you are asked for one). It shows how to handle linear elasticity problems in 2D and 3D. Then, to go from linear to non-linear, you will have to modify a few section of the code :

·         In the “Function” definitions, the tensor C_m as a function of the displacement components [ux, uy].

·         In the “Formulation” section, you will possibly want to decompose the non-linear term instead of using C_m[ { u } ] * Dof[ { D1 u } ].

·         In the “Resolution” section, you will have to add an IterativeLoopN that will take care of the non-linearity (more information on this page<https://onelab.info/trac/getdp/wiki/IterativeLoopN>).
And I guess that is all.

On the other hand, if you want to try Cast3M, have a look on the documentation here<http://www-cast3m.cea.fr/index.php>. Plus, there is a lot of example on how to solve mechanical problems. It might not be exactly what you are looking for but this test case<http://www-cast3m.cea.fr/index.php?page=exemples&exemple=compression_nloc> should give you an idea on how you can simulate your problem.

Best regards,

Guillaume Dilasser

De : gmsh [mailto:gmsh-bounces at ace20.montefiore.ulg.ac.be] De la part de Sandeep Jagadeesh
Envoyé : lundi 27 juin 2016 19:46
À : gmsh at onelab.info
Objet : [Gmsh] Material non-linearity simulation help

I would like to know if it is possible to simulate 'compression test of polymer foams (material non-linearity)' in GMSH. If possible please help me with the methodology and any tutorial. It would be of great help to me in this regard.

Thanking You
Anna University,
Chennai, Tamil Nadu,
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