missing stress values Sxy, Syz, Szy

About the development of the FEM module/workbench.

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HarryvL
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Re: missing stress values Sxy, Syz, Szy

Postby HarryvL » Wed Jan 30, 2019 4:14 pm

Yes it is already used extensively.
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bernd
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Re: missing stress values Sxy, Syz, Szy

Postby bernd » Wed Jan 30, 2019 6:52 pm

HarryvL wrote:
Wed Jan 30, 2019 4:14 pm
Yes it is already used extensively.
and it is great to have it, but does not help if we gone disscuss property data structure of FreeCAD objects ...
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bernd
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Re: missing stress values Sxy, Syz, Szy

Postby bernd » Fri Feb 08, 2019 11:38 am

I have something working ...

how about these names for VTK ?

Screenshot_201998.png
Screenshot_201998.png (42.8 KiB) Viewed 227 times
Screenshot_201999.png
Screenshot_201999.png (54.96 KiB) Viewed 227 times

code is here. First the FreeCAD result property name than the VTK name ... https://github.com/berndhahnebach/FreeC ... #L661-L703

If someone would give it a try which is highly appreciated ... https://github.com/berndhahnebach/FreeC ... ultreading
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HarryvL
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Re: missing stress values Sxy, Syz, Szy

Postby HarryvL » Fri Feb 08, 2019 2:09 pm

Great!! Some really minor comments:

I would start “strain” with capital letter (ie Strain)

I would put them in the following order:

xx, yy, zz, xy, xz, yz (Just for convention sake. Same applies to stress)

I would drop “Cauchy” and capitalize Stress. There are many different stress measures, but the default is Cauchy. So if nothing is mentioned it is clear Cauchy is meant.

I would drop “magnitude” after Principal Stress.

PS: I am traveling so won’t be able to test soon
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bernd
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Re: missing stress values Sxy, Syz, Szy

Postby bernd » Fri Feb 08, 2019 2:58 pm

great ... I will do the changes in the regard of you comments. One hint ... stress and strain conventions I used from CalculiX frd file. See https://github.com/FreeCAD/FreeCAD/blob ... #L844-L850 But if yours ist standard FEM mathematics I would use yours.

Have you seen https://github.com/berndhahnebach/FreeC ... #L661-L703 the names in FreeCAD result property for stress and strain are NodeStressXX and NodeStrainXX ... How about them?

BTW they work in FEM result object user defined view as well as in vtk and in vtk file export. Means full access to them.

Testing ist not that important (I mean only in sense of the names, otherwise testing is highly apreteated any time :) ). I will rebase your concrete branch on that. For this some dev and testing will be required than. But thats another topic and story ...
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HarryvL
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Re: missing stress values Sxy, Syz, Szy

Postby HarryvL » Fri Feb 08, 2019 3:20 pm

bernd wrote:
Fri Feb 08, 2019 2:58 pm
(1) One hint ... stress and strain conventions I used from CalculiX frd file.

(2) NodeStressXX and NodeStrainXX ... How about them?

(3) I will rebase your concrete branch on that. For this some dev and testing will be required than. But thats another topic and story ...
(1) I can only express my preference :)
(2) That is good alternative. Just so people know it’s nodal values and not at integration points.
(3) Just let me know if, how and when I can help.
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bernd
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Re: missing stress values Sxy, Syz, Szy

Postby bernd » Sun Feb 10, 2019 1:00 pm

changed names and order

https://github.com/berndhahnebach/FreeC ... #L661-L703

had to change calculation of principal and von mises stress too ...

https://github.com/berndhahnebach/FreeC ... #L327-L355
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HarryvL
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Re: missing stress values Sxy, Syz, Szy

Postby HarryvL » Sun Feb 10, 2019 5:33 pm

bernd wrote:
Sun Feb 10, 2019 1:00 pm
changed names and order

https://github.com/berndhahnebach/FreeC ... #L661-L703

had to change calculation of principal and von mises stress too ...

https://github.com/berndhahnebach/FreeC ... #L327-L355
Ah, great, I tested it this morning, but with the old names. I'll try once more
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bernd
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Re: missing stress values Sxy, Syz, Szy

Postby bernd » Mon Feb 11, 2019 6:10 am

HarryvL wrote:
Sun Feb 10, 2019 5:33 pm
Ah, great, I tested it this morning, but with the old names. I'll try once more
Just fixed the result task panel with the new names. From my point of view https://github.com/berndhahnebach/FreeC ... ultreading is ready for a PR. Would be great if you could give it another try, as you stated
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HarryvL
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Re: missing stress values Sxy, Syz, Szy

Postby HarryvL » Mon Feb 11, 2019 2:29 pm

Looks good. I tried both result pipeline and Paraview and all descriptions are the same and make sense to me.