[Gmsh] Selection of element type during Mesh generation

[Christophe Geuzaine]

> On 29 Jul 2019, at 05:25, VARSHA GOEL <varshagoel94 at gmail.com> wrote:
> 
> Hello 
> Thank you for the prompt reply. The most common element type  for 3 node triangle is S3 for abaqus format.

Ok. Here's what we current output:

2-node line: T3D2
3-node triangle: CPS3
6-node triangle: CPS6
4-node quad: CPS4
8-node quad: CPS8
4-node tetra: C3D4
10-node tetra: C3D10
8-node hex: C3D8
20-node hex: C3D20
27-node hex: C3D27
6-node prism: C3D6
15-node priem: C3D15

Looking at https://www.sharcnet.ca/Software/Abaqus610/Documentation/docs/v6.10/books/usb/default.htm?startat=pt10eli01.html it seems that, for 2D elements at least, it's going to be impossible to satisfy everybody, as the element type also encodes the physics. For 3-node triangles for example I see CPE3 (plane strain), CPE3E (plane strain piezzo), CPE3T (plain strain thermally coupled), CPEG3 (generalized plane strain), CPS3 (plane strain - what we currently output), S3 (general purpose shell, finite membrane strains), etc.

Switching to S3 for 3-node triangles as you suggest could then indeed make sense, but there doesn't seem to be a 6-node equivalent... Using "S3" and "CPS6" for 3- and 6-node tris respectively is sure to be even more confusing.

I'm wondering if there is a solution to this issue beside either providing all choices, or providing some option for each element type. I'm not sure if this is worth the trouble though, and if simply post-processing the output with "sed" would not be enough.

Christophe




> 
> On Thu, 25 Jul 2019, 17:58 Christophe Geuzaine, <cgeuzaine at uliege.be> wrote:
> 
> 
>> On 25 Jul 2019, at 12:01, VARSHA GOEL <varshagoel94 at gmail.com> wrote:
>> 
>> Hello,
>> 
>> I created a mesh using Frontal Delaunay Algorithm for a CAD geometry.On being exported
>> to Abaqus .inp format , i found that the element type being generated is CPS3 type tria element.I want the mesh to have S3 type elements.Please let me know how can i  set the element type.
> 
> You'll need to edit the source code in gmsh/Geo/MTriangle.h (getStringForINP() function). Our knowledge of the Abaqus format is limited: what would be the most general type to use for 3-node triangles?
> 
> Christophe
> 
> 
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> — 
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science 
> http://www.montefiore.ulg.ac.be/~geuzaine
> 
> 
> 

— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine