Principal Stress Plots

About the development of the FEM module/workbench.

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HarryvL
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Principal Stress Plots

Postby HarryvL » Wed Jun 20, 2018 9:41 pm

As a step towards plotting stress trajectories (see https://forum.freecadweb.org/viewtopic. ... 85#p237229) I managed to export principal stress directions to Paraview VTK. Here the example of a block under pure shear conditions:

Shear_Input_004.png
Shear_Input_004.png (243.45 KiB) Viewed 1187 times

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Shear_Result_004.png
Shear_Result_004.png (276.73 KiB) Viewed 1187 times

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Principal_Stresses_004.png
Principal_Stresses_004.png (253.72 KiB) Viewed 1187 times

As can be seen from the Paraview plot, the principal stress directions (+/- 45 degrees) and values (+/- 1000MPa) agree with the applied shear stresses.

To be continued...
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Wed Jun 20, 2018 10:24 pm

... and here the results for a cantilever beam

Cantilever_Input_003.png
Cantilever_Input_003.png (197.92 KiB) Viewed 1182 times

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Principal_Stresses_003.png
Principal_Stresses_003.png (136.76 KiB) Viewed 1182 times
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Wed Jun 20, 2018 11:21 pm

... and a knee joint:

Knee_Joint_Input_005.png
Knee_Joint_Input_005.png (266.3 KiB) Viewed 1178 times

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Principal_Stresses_005_2.png
Principal_Stresses_005_2.png (243.02 KiB) Viewed 1178 times

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Principal_Stresses_005_3.png
Principal_Stresses_005_3.png (137.01 KiB) Viewed 1178 times

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Principal_Stresses_005_4.png
Principal_Stresses_005_4.png (380.31 KiB) Viewed 1178 times

To be continued ...
Jee-Bee
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Re: Principal Stress Plots

Postby Jee-Bee » Thu Jun 21, 2018 8:45 am

Are you trying to implement the results also in FC or just the calculation method?
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Thu Jun 21, 2018 9:37 am

Jee-Bee wrote:
Thu Jun 21, 2018 8:45 am
Are you trying to implement the results also in FC or just the calculation method?
Hi @Jee-Bee. Paraview is a very strong and versatile tool and the link with FC is quite simple. So I am not sure that trying to replicate and maintain Paraview capability inside FreeCAD is the best use of our time. What is your view?
Jee-Bee
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Re: Principal Stress Plots

Postby Jee-Bee » Thu Jun 21, 2018 9:42 am

I don't have used it. so i don't know what the possebilities are and or how it's working :oops:
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Thu Jun 21, 2018 10:08 am

Ah ok. It's well worth a try. Simply export a VTK file from the result object. Paraview is very easy to use. I didn't read any manuals or guides - just Googled a bit and watched some videos :)
thschrader
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Re: Principal Stress Plots

Postby thschrader » Thu Jun 21, 2018 7:23 pm

HarryvL wrote:
Thu Jun 21, 2018 10:08 am
Ah ok. It's well worth a try. Simply export a VTK file from the result object. Paraview is very easy to use. I didn't read any manuals or guides - just Googled a bit and watched some videos :)
Harry, amazing work.
My wish is to see your plots in FC-pipeline results.
"Paraview is very easy to use" :D
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Thu Jun 21, 2018 9:04 pm

thschrader wrote:
Thu Jun 21, 2018 7:23 pm
My wish is to see your plots in FC-pipeline results.
I will give it a try when I find the time Thomas. It is difficult to choose standard settings though. It takes quite a bit of playing with scale factors, colors, line thicknesses, etc. to get an acceptable result. That flexibility is available to the user in Paraview, but not in the FC VTK pipeline. So I fear that the plots will look clunky, driving people towards Paraview anyway.

Priorities for me at the moment are as follows:
1) leave this and the concrete reinforcement ratios in an orderly state on github, so people can compile and test it
2) try to finish my routine for stress trajectories. I am quite excited about it, because I believe FC would be the first post-processor to have this functionality
3) finish my own 3D elastoplastic collapse solver. This will read regular INP and produce regular FRD) so can simply be called as alternative to CCX

Just too many ideas and too few hours in a day :D
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HarryvL
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Re: Principal Stress Plots

Postby HarryvL » Thu Jun 21, 2018 9:10 pm

A concrete wall 4.00x2.00x0.15m on 0.50x2.00x0.15m columns, loaded by self weight and 1MN distributed load on top ...

Wall_Input_006.png
Wall_Input_006.png (90.03 KiB) Viewed 1072 times

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Principal_Stresses_006_1.png
Principal_Stresses_006_1.png (407.87 KiB) Viewed 1072 times

Red = Major Principal Stress
Blue = Minor Principal Stress
Green = Intermediate Principal Stress