Converting standard stresses to Mises stresses

Hi all.

I load a d3plot file from LS-Dyna into the ParaView program. My task is to remove stresses exceeding 600 MPa (singularities). After loading the file, the first thing I want to do is convert the standard program stresses into von Mises stresses. For this I did not find a standard button and use a calculator. I use the formula:

sqrt(0.5*((S11-S22)^+(S22-S33)^2+(S33-S11)^2+6*(S12^2+S23^2+S13^2)))

but I get errors and it doesn’t work.
How to do it?

Next, I need to convert the stresses to GPa, because… When calculating in LS-Dyna I used this dimension, I also planned to use a calculator, for example like this:

S11*1e-9

but that won’t work either.

Give answers please. Thank you.

It might help if you gave the specific error or shared your data. That said, it looks like you missed the 2 after the first ^. That’s definitely a parse error.

>> That said, it looks like you missed the 2 after the first ^. That’s definitely a parse error.
Yes sir, I was in a hurry and wrote the formula by hand, so there was a mistake, I actually used a number there. I will show below a screenshot of the error and formula. I also tried using the form with and without quoted expressions:

Sir I have tried so many variations of the formula but they do not work. I couldn’t save the project, so I attached my d3plot file:

D3PLOT FILE

Can you open it and try to apply the formula?
Thank you.

Is that the only file associated with this dataset? When I try to open it in ParaView 5.12.0-RC3, it says not timesteps are defined.

I’m sorry sir! Yes, to open a d3plot file you need accompanying files, which contain the results of timesteps.
I saved the entire archive, now everything opens as it should.
D3PLOT

Help please

Thanks for posting your dataset. In your expression you are using variables like S11, S22, S33, and so on, but there are no such variables in your dataset. Are these supposed to be matrix elements from a stress variable?

You have a cell data array called Stress. Wild guess, but I think you want your expression to be

sqrt(0.5*((Stress_XX-Stress_YY)^+(Stress_YY-Stress_ZZ)^2+(Stress_ZZ-Stress_XX)^2+6*(Stress_XY^2+Stress_YZ^2+Stress_XZ^2)))

Make sure to change the Attribute Type to Cell Data in the Calculator so that these variables are accessible:

image

By the way, you can see which variables are available by clicking on the Scalars or Vectors menus:

image

If you select a variable from one of these menus, it will be inserted into the expression.

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Thanks Sir it works. But why don’t the values match?


As Kenneth_Moreland pointed out, the 2 is missing after the first ^.

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Thanks for your answer sir! Yes, I saw this error, but it still didn’t show up for me. I removed the calculator and added a new calculator and formula again, now everything works! Thank you!

Please tell me how you set up such a rainbow on the scale?
изображение

And my second question.
I remove some of the tensions (singularities) using the Threshold filter. How can I save the changes correctly in my d3plot file after applying these filters? After saving correctly, I plan to use this file again for further calculations in Ls-Dyna for fatigue.
Thank you!

Please tell me how you set up such a rainbow on the scale?

In Color Map Editor > Color Discretization > Number Of Table, specify 10.

With regard to the second question, it may be difficult to use ParaView to directly reflect some modifications of the data in the d3plot file, as there is no LS-DYNA writer in ParaView. If LS-DYNA can read other file formats that ParaView can output, it may be possible to pass the modified data.

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Can’t ParaView just save changes to a d3plot file that was opened for editing?

Unfortunately, ParaView does not have the ability to output to d3plot file format, so it is not possible to save the modified results as a d3plot file.

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