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Krande / adapy

A python library for structural analysis and design
https://krande.github.io/adapy
GNU General Public License v3.0
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code aster reduced integration element names #104

Open Krande opened 1 month ago

Krande commented 1 month ago

In connection with the issue raised in https://github.com/Krande/adapy/issues/101, I am currently adding basic support for specifying reduced integration for typical elements.

This is now done for calculix and abaqus, but I have still sesam and Code Aster remaning.

For Code Aster I have found two reference documents that describe in detail the theory and implementation of reduced integration for QUAD and HEX elements (see r3.06.10 and r3.06.11 in https://code-aster.org/doc/default/en/index.php?man=R3).

However, internally when writing these element types to MED, Code Aster does not use QUAD4/HEX8 names, instead they use an abbreviated form QU4/HE8.

So the question is, given the reduced integration variants are referred to as QUAS4/HEXS8 in the documentation, do they have different abbreviated names or are they activated by other means?

Krande commented 1 month ago

According to the reply I got here it seems I will have to modify the AFFE_MODELE param in my .comm files.

Hello Kristoffer,

you decide whether you work with reduced or fully integrated elements using the keyword AFFE_MODELE or "Assign finite element" in AsterStudy. code_aster assigns the element type to your mesh, which you define there under MODELISATION.

For TETRA and HEXA elements, 3D stands for the fully integrated elements and 3D_SI for the reduced integrated elements. Adding _SI to the element name usually switches to "reduced integrated".

You can find a list of all element types in the manual for AFFE_MODELE (U4.41.01) § 3.2.1. Here you will find references to manuals for the individual element types, e.g. U3.14.01 for 3D and 3D_SI. You will find all the details there.

Among other things, you can also read here which mesh you need to provide, for example from Salome.

As far as I know, 3D_SI is only possible for TETRA10 and HEXA20. So you have to convert the mesh into a quadratic first. You can do this directly in Salomes mesh module.

You can assign 3D to both linear (TETRA4 / HEXA8) and square networks (TETRA10 / HEXA20).

I hope I was able to answer your question.

Best regards, TOBI