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Inverse calibration using Mcal and Abaqus

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blackhole612
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I am modelling a 3D printed lattice structure so I need the material properties of the lattice build. therefore, I did some experimental compression tests on a single strand (material) to see what is the behaviour of material and seemed it is kind of crushable foam.

The geometry in abaqus is very simple (single circular bar). I followed all steps in the calibrate a material model using abaqus simulations pdf file (exist in Mcalibration tutorial) and created the same geometry and BC and create .inp file. (attached is .inp file and data from experimental test)

I saved .inp from abaqus along with .txt of experimental result at a location path :D:\abaqus_NSC\Mcalibration_abaqus

Then I check at mcalibration preferences button to make sure the specified path to abaqus is correct which is: C:\SIMULIA\Commands

The error faced when I click the run once button at Mcalibration is that:

Could not find the file: D:/abaqus_NSC/Mcalibration_abaqus/AbaExtSolver_LC_1.data [4]

Load case 1 (abaqus_mcalibartion_f_d_2) finished: final stress=0

Error: Could not calculate the fitness value.

Simulation done

I check the mentioned path and found that there is no file called AbaExtSolver_LC_1.data. after click run, the only files that created are AbaExtSolver_LC_1.inp, AbaExtSolver_LC_1.py and AbaExtSolver_mat_LC_1.inp Files in the directory after running the calibration.

I think the error probably related to the Mcalibration cannot run the abaqus file (or connect the abaqus) maybe due to installation path or something like that. What do you reckon? I attached .mcal file as well and you can run it.

Can you please help me to find a solution as I dont know what the main factor that cause the error and would be highly appreciated to help me?

Best Regards
Maedeh

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Jorgen
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Interesting problem. Your zip-file contains a data file with 3 columns. I assume column 1 is time, column 2 is displacement, column 3 is force. Is that right?

I then noticed that your Abaqus inp-file has the following step definition:
[CODE]*Step, name=Step-1, nlgeom=NO
*Static
1., 1., 1e-05, 1.[/CODE]

That is wrong. The STATIC step need to follow the same applied displacement history as in your experimental data file (Specimen_RawData_1.csv). The final time point in your experimental data file is 195.38802, so your step needs to have the same final time.

Also, you should divide your STEP into multiple increments, and I think you should turn on NLGEOM=ON.

There might be other issues, but try these changes first.

-Jorgen

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blackhole612
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Thanks Jorgen,
I modified it (please find the attached modified .inp file) but there is still the same error. I think something is related to that Mcalibration cannot link to abaqus and find the .data file. is there any thing that I should do before running Mcalibratin e.g pre-installation requirement??

I would say I only installed trial licence of Mcalibration (not Polyumod) and I sent many email to Veryst to purchase an academic licence but still waiting for their response.(after about 4 days).
As my research got stock due to the inverse calibration using abaqus and Mcalibration, I highly appreciate if you can please assist me in this point.

Regards
Maedeh

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Jorgen
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There was something wrong with your mcal-file. I recreated it by: (1) starting a new MCalibration window, (2) reading in the experimental data, (3) copying over your plasticity model from the original mcal-file.

Heres a screen shot:

I then clicked Run Once to see what your Abaqus FE simulation is doing. The simulation starts just fine, but the deformation field seems odd. This is what I see:

Is that what the deformation should look like?

-Jorgen

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Jorgen
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Use the following [URL= https://verystsoftware.atlassian.net/servicedesk/customer/portal/3]web-page[/URL] to purchase an academic version of MCalibration.

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blackhole612
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Thanks Jorgen,

I am just really confused and frustrated as I open the attached mcal file you sent and run it , the same error happened again !!!
can you please let me know if the path of abaqus (in preferences) should be the same as the path of saved .inp file and .txt (experimental file).
in other words, where should I save the .inp file, text file?

about the deformation, it is wrong as I applied the 0.8 mm compression displacement on top of the strand line and fix the bottom line.
Do you think it is the correct BC based on experimental test?

Thanks a lot for all your hep on this point.
Maedeh

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Jorgen
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The path of Abaqus that is specified in the Options Dialog box should be the path to the script that starts Abaqus. Here is an image from my Linux computer.

On a Windows computer the abaqus run script typically ends with .bat. For example: abq2019.bat

Note that this path has nothing to do with the inp-file or the experimental data file. You can save the inp-file, the experimental data file anywhere you like on your computer. Note that you should save your mcal-file in that same directory.

It sounds from your last message that the inp-file that you provided does not apply the deformation field that you had in mind. I recommend that you fix that.

-Jorgen

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