Post processing for superposition effect

General Questions
1

Good morning,

I am working on two files of the same project. I did it in order to use superposition effect, because a rigid body constraint has a negative effect on a certain load.
So, I exported the stresses ‘’.dat’’ files of the same regions, and merged the values by using Excel.

Is there a way to visually display the merged stresses? I.e. a software that displays the 3D model and the combined stresses at the same time. Beacuse that option could be more understandable instead of an excel file of merged values.

Thank you

2

I would recommend ParaView for this purpose. It’s a really powerful postprocessing tool and will definitely let you do this. I showed some basics here: PrePoMax (CalculiX FEA) - Tutorial 26 - Thermo-mechanical analysis of a thick pipe (with ParaView) - YouTube

2 Likes
4

Thank you,

I saw tutorials of this software, but I haven’t found how to perform a superposition effect. I created two .VTK file, but I don’t know how to merge the models.

5

Use the Programmable Filter tool with a script like this:

v_0 = inputs[0].PointData['variable_name']
v_1 = inputs[1].PointData['variable_name']
output.PointData.append(v_1 + v_0, 'sum')

Then select sum for contour plot.

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6

Superposition of results only applicable for linear analysis, no plasticity or large deformation. In case of nonlinear analysis, it’s required the load to be combine before the analysis performed.

7

In ‘variable_name’ I have to put the name of the .vtk file opened, isn’t it?

8

No, the name of the output variable that you want to be summed over two data sets. Depends on how it’s displayed in ParaView. It can be ‘Displacement Magnitude’ for instance.

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9

I’m not so good in programming, so, I don’t know how to correctly define that script. I want to merge the Von Mises stress of the two .vtk files.
Where do I need to define v_0 and v_1?
Then, how can I use the programmable filter tool on windows version?

Thank you in advance

10

Just paste that code into the programmable filter’s input field and substitute the name of the output variable, no need to define anything else.

11

I did as you said, but on coloring section desn’t appear Von Mises Stress. Contour1 and Contour2 are Von Mises Stress of the two .vtk file.

image
image716×752 35.1 KB

12

Is “sum” selected as a variable to be plotted ?

13

I am trying but I don’t know where to modify into sum.

14

sum
sum707×157 32.2 KB

15

I don’t know why I haven’t it, neither on ‘‘Programmable filter’’.
image

16

What are those Contour1 and Contour2 objects ? There should be just 2 vtk files and 3 objects named ProgrammableFilter1.

17

These are the contour plot. I deleted them, now this is displayed:

image
image647×816 59 KB

18

Can you share these two .vtk files here ?

19
20

Shapes/meshes are different, they should be the same for this procedure to work. Ask here if you want to know if there are any other ways to achieve similar result: https://discourse.paraview.org/

21

Thank you for the support.