fcFEM - FEA from start to finish

About the development of the FEM module/workbench.

Moderator: bernd

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HarryvL
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Re: fcFEM - FEA from start to finish

Postby HarryvL » Sun Mar 24, 2019 2:47 pm

Wait that’s not right. This is a pit of 8x8x4m deep.
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HarryvL
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Re: fcFEM - FEA from start to finish

Postby HarryvL » Sun Mar 24, 2019 3:14 pm

Now 4x4x4m:


fcFEM_Pit_4x4x4.jpg
fcFEM_Pit_4x4x4.jpg (75.62 KiB) Viewed 394 times

fcFEM_Pit_4x4x4.png
fcFEM_Pit_4x4x4.png (36.66 KiB) Viewed 394 times

Trench_Collapse_4x4x4.png
Trench_Collapse_4x4x4.png (208.92 KiB) Viewed 394 times


Now 38% stronger, but still not enough. This pit will collapse when reaching 3m depth or so.
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bernd
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Re: fcFEM - FEA from start to finish

Postby bernd » Sun Mar 24, 2019 3:27 pm

yeah this is what I like ... real 3D excavations !
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bernd
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Re: fcFEM - FEA from start to finish

Postby bernd » Sun Mar 24, 2019 3:43 pm

most engineering tools only allow 2D excavation and soil analysis.
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bernd
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Re: fcFEM - FEA from start to finish

Postby bernd » Mon Mar 25, 2019 6:51 am

HarryvL wrote:
Tue Mar 19, 2019 9:52 am
With as an obvious simplification:

Code: Select all

normal=stress[:3]
shear=stress[3:]
pressure=np.average(normal)
sig_mises=np.sqrt(1.5*np.linalg.norm(normal-pressure)**2+3.0*np.linalg.norm(shear)**2))
;)
there is one ")" to much above at the end ...

Code: Select all

  
normal=stress[:3]
shear=stress[3:]
pressure=np.average(normal)
sig_mises=np.sqrt(1.5*np.linalg.norm(normal-pressure)**2+3.0*np.linalg.norm(shear)**2)

like this: https://github.com/berndhahnebach/FreeC ... diff=split ? :)

I added a unit test lately. It still is ok :) The von mises test only coúld be run on linux with:

Code: Select all

./bin/FreeCAD --run-test "femtest.testresult.TestResult.test_stress_von_mises"
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HarryvL
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Re: fcFEM - FEA from start to finish

Postby HarryvL » Mon Mar 25, 2019 10:07 am

Yes, like that :D. It looks more Pythonic and should be slightly faster.
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bernd
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Re: fcFEM - FEA from start to finish

Postby bernd » Mon Mar 25, 2019 11:10 am

HarryvL wrote:
Mon Mar 25, 2019 10:07 am
Yes, like that :D. It looks more Pythonic and should be slightly faster.
BTW: what is best to name the tuple for the 6 stress components. Ist stresstuple fine, or just stress (I don't like this), or stresstensor or whatever ? We gone make some use of it in femconcrete branch too. https://github.com/berndhahnebach/FreeC ... f6e4e5L473
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PrzemoF
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Re: fcFEM - FEA from start to finish

Postby PrzemoF » Mon Mar 25, 2019 11:20 am

stress_tensor sounds fine. I don't like to name variables after type. If down the line you change the type for some reason you'll have to change variable name as well.
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HarryvL
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Re: fcFEM - FEA from start to finish

Postby HarryvL » Mon Mar 25, 2019 12:24 pm

I agree
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bernd
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Re: fcFEM - FEA from start to finish

Postby bernd » Wed Mar 27, 2019 2:01 am