Quick tutorial for your first simulation with Code_Aster (after instalation)

We will run the use case sdld02a from the examples/benchmarks provided with code_aster. The examples can accessed in the directory : aster-full-src-xx.x.x/SRC/aster-xx.x.x/astest, where xx.x.x is your downloaded Code_Aster version.

STEP 1 : Copy the following files to your working directory 

- sdld02a.comm : command file 

- sdld02a.mail : meshing file

- sdld02a.export :  parameters file. this post explains how to create a basic export file.


STEP 2 : RUN the model with the command

as_run sdld02a.export

You may add a line with :

P mode interactif

to the .export file. If your get an error “file not found : config.txt“, then you should check your export file. Make sure to not mix up different kind of new-lines otherwise the export file parser may have difficulty to load your  export file. Finally adding the line (XX.X is your Code_Aster version)

 P version XX.X

may help locate the right config.txt.

Documentation about this use case is available here. It solves a two-dimensional problem consisting of finding the frequencies and modes of vibration of a mechanical structure composed of 8 masses and 7 springs. This benchmark corresponds to a dynamic analysis of a discrete model with linear behavior.


STEP 3 : View your model

In order to view your model with a software like Paraview you need first to export a 'med' file during your simulation. For this add to your 'comm' file the following command and re-run the simulation.

# Impression au format MED du fichier de maillage après modification

unit2=DEFI_FICHIER(ACTION='ASSOCIER', ACCES='NEW',TYPE='LIBRE', FICHIER='/home/user/test.med',)

IMPR_RESU(UNITE=unit2,FORMAT='MED',RESU=_F(MAILLAGE=MA, RESULTAT= FREQ ,),)

DEFI_FICHIER(ACTION='LIBERER',UNITE=unit2,)

DETRUIRE(CONCEPT=_F(NOM=unit2),INFO=1,)


If you build your own mesh, using gmesh, then make sure to use the 2.2 version of gmesh. Example :

gmsh -3  geometry_file.geo -format msh2

then you can use, the PRE_GMSH command in Code_Aster to load the gmsh mesh.

in the course, we use simscale to view the model. simscale is a cloud basis CFD and FEM suite based on OpenFoam and Code_Aster. You need top create a free account to use it. Once you have your account go to your Dashboad, create a new folder and then a new project. Once you created a new project you drag and drop the med file from your simulation to view it.



Click on Create Folder, then double click on the new created folder (e.g. POSTPROCESS) to create a project inside. 


You can also use SalomeMeca to view the model.

You need to install first the Singularity container : sudo apt-get install -y singularity-container

(see also: https://www.linuxwave.info/2022/02/installing-singularity-in-ubuntu-2004.html)


Then download the '.sif' file from the Salome Meca website.

Then : singularity run --app install salome_meca-lgpl-2021.0.0-1-20210811-scibian-9.sif 


Alternatively you can download a 'salome_meca-xxx.run' file from Salome website and execute it in a terminal with : 

./salome_meca-xxx.run