nice picture in FEM module wiki, but it is wrong IMHO

About the development of the FEM module/workbench.

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vocx
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Re: nice picture in FEM module wiki, but it is wrong IMHO

Postby vocx » Wed Apr 17, 2019 9:11 pm

Jee-Bee wrote:
Wed Apr 17, 2019 7:23 pm
My personal workflow is materials first than constraint and final the mesh.
The reason i put mesh on the bottom is that it interacts with external software. When the arraows are added it gives more unneeded clutter.
Arrows add too much clutter? I personally think that it's one of the best things that humanity ever invented. Knowing how information flows is critical in understanding the relationships between the parts. Imagine if the dependency graph didn't have arrows pointing to the blocks.
vocx
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Re: nice picture in FEM module wiki, but it is wrong IMHO

Postby vocx » Wed Apr 17, 2019 9:26 pm

bernd wrote:
Wed Apr 17, 2019 8:27 pm
I must admit, Surely this has some points too. For the geometry I have I never did this, but my geometry usually does not have geometrical errors and is rather simple for our meshers.

We might should the user let decide ... and put them all 3 as Jee-Bee had it on the same step.
I purposefully put the mesh in its own block because it uses an external application. This makes it evident that an external piece of software is being used. Obviously in FreeCAD you can quickly define the geometry, the analysis, and then mesh inside FreeCAD; this is simple to do for simple geometry, and if you don't mind having only triangles and tetrahedra. But for complex geometrical elements, I wonder, do people really mesh inside FreeCAD? I would expect an experienced user to mesh the geometry with an external program to really control all details and produce an all-quad all-hexahedra mesh. I think this is what -alex- is referring to.

In traditional FEA, the mesh is one of the critical steps. But again, it depends on your own usage. It's not the same doing crash simulations, and doing structural simulation. Small deformation cases, like structural analyses, work well with triangular meshes, but large deformation time-dependent simulations do not.
Jee-Bee
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Location: Netherlands

Re: nice picture in FEM module wiki, but it is wrong IMHO

Postby Jee-Bee » Thu Apr 18, 2019 5:13 am

vocx wrote:
Wed Apr 17, 2019 9:11 pm
Arrows add too much clutter?
No arrows trough other boxes add to much clutter. It should be something like "I create the mesh at the bottom otherwise ..."
I didn't add the arrows because i was lazy and want show something fast :lol:
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Gurbhej Singh
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Re: nice picture in FEM module wiki, but it is wrong IMHO

Postby Gurbhej Singh » Sun Apr 21, 2019 4:51 am

Greetings for the day,
According to the work I have done with the FEM workbench meshing has to be done before the constraint and force step. Because sometimes some changes are required to achieve success in proper meshing. Due to these changes problem in analysis occurs If we apply constraint and force before the meshing.

Also according to the FreeCAD manual https://www.freecadweb.org/manual/a-freecad-manual.pdf, the steps for the FEM analysis were
a) Analysis
b) Meshing
C) Material
d) Constraint
e) Force
F) Solver
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Sudhanshu
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Re: nice picture in FEM module wiki, but it is wrong IMHO

Postby Sudhanshu » Sun Apr 21, 2019 5:50 am

I am not really an experienced FEM WB user, so I did a bit of research and found that though the order of pre-processing steps varied in various blogs and articles, but the generally followed order was:

1. Create 3D model
2. Setup Analysis
3. Assign Material
4. Create Mesh
5. Add Constraints
6. Add Forces

Some of the links that I referred to are this one and this one.

Also, in my opinion, we should consider the things like:

1. What steps are followed if we do FEM analysis without using softwares?
2. What workflow do other FEM/CAD softwares follow?