## Principal Stress Plots

About the development of the FEM module/workbench.

Moderator: bernd

HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Principal Stress Plots

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 (243.45 KiB) Viewed 2502 times

-

Shear_Result_004.png (276.73 KiB) Viewed 2502 times

-

Principal_Stresses_004.png (253.72 KiB) Viewed 2502 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...
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

... and here the results for a cantilever beam

Cantilever_Input_003.png (197.92 KiB) Viewed 2497 times

-

Principal_Stresses_003.png (136.76 KiB) Viewed 2497 times
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

... and a knee joint:

Knee_Joint_Input_005.png (266.3 KiB) Viewed 2493 times

-

Principal_Stresses_005_2.png (243.02 KiB) Viewed 2493 times

-

Principal_Stresses_005_3.png (137.01 KiB) Viewed 2493 times

-

Principal_Stresses_005_4.png (380.31 KiB) Viewed 2493 times

To be continued ...
Jee-Bee
Posts: 2181
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

### Re: Principal Stress Plots

Are you trying to implement the results also in FC or just the calculation method?
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

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
Posts: 2181
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

### Re: Principal Stress Plots

I don't have used it. so i don't know what the possebilities are and or how it's working
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

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
Posts: 1967
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: Principal Stress Plots

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"
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

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
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

### Re: Principal Stress Plots

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 (90.03 KiB) Viewed 2387 times

-

Principal_Stresses_006_1.png (407.87 KiB) Viewed 2387 times

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