# Post Processing Stresses Output

**URL:** <https://prepomax.discourse.group/t/post-processing-stresses-output/1444>\
**Category:** General Questions\
**Created:** [January 24, 2024, 10:19am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444 "2024-01-24T10:19:57Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\
**Post date:** [January 24, 2024, 10:19am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/1 "2024-01-24T10:19:57Z")

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Dear Sir, Good day.  
Regarding the stress output, Von mises and Tresca are easy to find.

1. I would like to clarify Sir which one is Membrane stress, Out of Plane stresses, normal stress and In plane stresses, shear stress among S11, S22, S33, S12, S23, S13.
2. Is there any way, or command we can apply where we can display the stress Vector along x, along y, along z ? Thank you sir and really appreciate for your kind inputs.  
 ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/9/960faa19069cb45001da0b91669fba64616cd043.png)

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [January 24, 2024, 10:28am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/2 "2024-01-24T10:28:34Z")

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> [@jsarocena](#):
>
> I would like to clarify Sir which one is Membrane stress, Out of Plane stresses, normal stress and In plane stresses, shear stress among S11, S22, S33, S12, S23, S13.

The stress components are in global coordinates. So S11, S22 and S33 are normal stresses (SX, SY, SZ) while S12, S23 and S13 are shear stresses (SXY, SYZ, SXZ). Local coordinates aren’t currently supported in PrePoMax and you would need keyword edits to use them, if needed.

> [@jsarocena](#):
>
> Is there any way, or command we can apply where we can display the stress Vector along x, along y, along z ? Thank you sir and really appreciate for your kind inputs.

No, such plots are not yet available but you could use the Glyph filter in ParaView for that.

> [@Converting results to ParaView format](https://prepomax.discourse.group/t/converting-results-to-paraview-format/453):
>
> ParaView doesn’t support CalculiX’s results (.frd) files but there are several converters to .vtk format available: FreeCAD: a) Import the .frd file b) Select the Results object in the tree c) Export to .vtk note: FreeCAD’s FEM module currently displays results in SI(m) unit system and the conversion will also write the results in this unit system [GitHub - calculix/ccx2paraview: CalculiX to Paraview converter (frd to vtk/vtu). Makes possible to view and postprocess CalculiX analysis re…](https://github.com/calculix/ccx2paraview)

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**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\
**Post date:** [January 25, 2024, 5:23am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/3 "2024-01-25T05:23:19Z")

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> [@FEAnalyst](#):
>
> The stress components are in global coordinates. So S11, S22 and S33 are normal stresses (SX, SY, SZ) while S12, S23 and S13 are shear stresses (SXY, SYZ, SXZ).

😍 Thank you very much Sir Jakub, really appreciate for your kind advise.

> [@FEAnalyst](#):
>
> No, such plots are not yet available but you could use the Glyph filter in ParaView for that.

😍 Thanks a lot, I will try and explore Paraview converter.

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**Author:** ![ANYS](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/anys/32/7737_2.png) [@ANYS](https://prepomax.discourse.group/u/ANYS)\
**Post date:** [January 25, 2024, 7:35am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/4 "2024-01-25T07:35:22Z")

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Hi,

When comparing Prepomax results against tabulated values (e.g. Rp0.2%,Rm,…) keep in mind the difference between True and Engineering Stress.  
Up to the Yield point the difference is typically small but if you intend to look beyond, the difference might be noticeable.  
All CalculiX input and output is in terms of True stress. Tabulated values are Engineering Stresses.

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**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\
**Post date:** [January 26, 2024, 4:51am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/5 "2024-01-26T04:51:45Z")

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> [@Converting results to ParaView format](https://prepomax.discourse.group/t/converting-results-to-paraview-format/453/1):
>
> GitHub - calculix/ccx2paraview: CalculiX to Paraview converter (frd to vtk/vtu). Makes possible to view and postprocess CalculiX analysis results in Paraview. Generates Mises and Principal components for stress and strain tensors.

Dear Sir Jakub, Good day to you. I’m verry sorry I am not yet successfully overcome this Paraview and Ccx2paraview how to use it, as I am not good in python. Appreciate if there is a direct command in edit/calculix keywords? Im happy with the visual where I can display the Von mises at the support and midspan using Tools query. However I cant do it to display the Reaction at the support. I really appreciate if you could advise me how to do it. Thank you and appreciate any advise you can share.

 ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/4/4fb0e043d993f3013e3744b4517f56c54a80a7b2.png)

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [January 26, 2024, 8:08am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/6 "2024-01-26T08:08:56Z")

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You could also try converting the .frd file to ParaView in FreeCAD but ccx2paraview is really easy to use. Try following the instruction in the referenced post. You may have to install Python first but it’s also simple.

> [@jsarocena](#):
>
> However I cant do it to display the Reaction at the support. I really appreciate if you could advise me how to do it.

The best way to get total reaction forces is to create a nodal history output request with RF for region(s) with applied BC(s). If you set Totals to Only, you will get the sum of reaction forces.

Another way is to use FORC contour plots and Query to get the sum at a given location.

 ![output](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/d/d3351ae20dd23fa13918e92395aedc6526b8acb4.png)

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<div class="post-metadata">

**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\
**Post date:** [January 26, 2024, 12:11pm UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/7 "2024-01-26T12:11:16Z")

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> [@FEAnalyst](#):
>
> The best way to get total reaction forces is to create a nodal history output request with RF for region(s) with applied BC(s). If you set Totals to Only, you will get the sum of reaction forces.
> 
> Another way is to use FORC contour plots and Query to get the sum at a given location.

Dear Sir Jakub, thank you so much. I’m ok with what you share, as I can display and view now the Total Reaction as per your advice. Thanks a lot. 😍

Meantime I will also explore the option of Paraview and CCx2paraview seems very interesting and a lot of features is there. Thank you for sharing a very helpful information.

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [January 26, 2024, 3:03pm UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/8 "2024-01-26T15:03:17Z")

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> [@jsarocena](#):
>
> Meantime I will also explore the option of Paraview and CCx2paraview seems very interesting and a lot of features is there. Thank you for sharing a very helpful information.

Yes, ParaView is a really powerful postprocessing software. I showed some of its capabilities (and conversion from .frd to .vtk) in this tutorial: [https://www.youtube.com/watch?v=wRcTD1zSbLU](https://www.youtube.com/watch?v=wRcTD1zSbLU)

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**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\
**Post date:** [February 9, 2024, 4:42am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/9 "2024-02-09T04:42:38Z")

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Dear Sir, Good day.  
Appreciate if you could help me how to deal with this error message from ParaView:  
After I load state the converted vtk file, error message appear in Paraview as shown below:

 ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/d/d1aeb03a6ee3b804bc112daf5d109013d4e9462b.png)  
Thank you in advance and really appreciate your kind assistance.

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [February 9, 2024, 7:49am UTC](https://prepomax.discourse.group/t/post-processing-stresses-output/1444/10 "2024-02-09T07:49:25Z")

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It might be better to ask here: [https://discourse.paraview.org/](https://discourse.paraview.org/)

If you can share your data there because they will need it to find the source of the problem.
