A physics-based simulation tool for replicating the deformation process of cubic microstructures across different operating systems.
Inputs: 1) Processing sequence (param files - explained below) 2) Process strain rate (param files - explained below) 3) Initial Orientation Distribution Function i.e., ODFs (76 independent values to be sampled for cubic microstructures)
Outputs: 1) Final ODFs including nine intermediate steps (demonstrating the microstructure after processing) 2) Cauchy Stress Tensor (3x3) (homogenized property of the microstructure)
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This code is written for the BCC and FCC crystal structures which have 76 independent crystal orientations with a total of 145 orientations. Crystal orientation is defined by the Orientation Distribution Function (ODF). Therefore, BCC or FCC has 76 independent ODFs and 145 total ODFs (dependent and independent).
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In "Simulator" folder, there is an executable file named "app.exe" which performs the process simulation. We need to run this app to get the results.
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We can control the loading conditions using "param.txt" file and the initial (input) ODF values using "Input_ODF.txt" file.
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The input file name must be named as "param.txt" to run the "app.exe". Otherwise, the code will give an error. Therefore, the MATLAB code will always produce a "param.txt" file for any loading condition.
For your reference, "param_tension/compression.txt","param_plane_strain_compression.txt", "param_xyshear.txt","param_yzshear.txt", and "param_xzshear.txt" files are provided in the Simulator folder. Please change the name to "param.text" before running the processing condition you would like (tension/compression, plane strain compression, xy_shear, xz_shear, and yz_shear).
For singular loading, the corresponding param file only contains one non-zero value (strain-rate), indicating the load direction.
For a combined loading condition (for example tension and xy shear applied together) we will provide two non-zero values (which are strain rates for the given loading condition) in the param file at the corresponding space (direction).
- Please note that the input ODFs (independent microstructure orientations) must satisfy two constraints: (i) the normalization constraint which is: sum of (volume fraction*ODF) = 1; (ii) ODFs cannot be negative (ODF>=0).
The MATLAB code includes the commands to ensure that ODFs are satisfying these two conditions.
- The code is written for 0.1 sec of loading time. We can monitor the change in the ODFs in each 0.01 sec time step. Therefore, we will have 10 ODF vector outputs in each run.
If we want to run the process for 0.3 sec, for example, we have to run the code three times. After each run, final ODFs should be input ODF of the next run.
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We cannot make any change in the input file named "input.txt".
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A MATLAB code is provided to make the process simulation automatic for multiple runs and to save the necessary output files for analysis.
The MATLAB file name is "process.m" is located in Simulator folder. Each step is explained within the code. Two '.mat' files named "newmesh.mat" and "cubicstructuredata.mat" are loaded before the main code.
The code will work for a particular loading condition (single or combined loading) for multiple runs. However, if we need to make different loading in each run we can not use the 'for' loop. We have to execute the first loading, then we need to wait for obtaining the output which can be used as the input ODFs for the next run which has a different loading condition. This is happening because each time the input file of loading should be named as "param.txt".
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After each run a "stress-strain.out" file will be generated that include the Cauchy Stress Tensor (material property output). Matlab code is also saving this output. Each run will generate 10 Cauchy Stress Tensors. Therefore, if we run 3 times it will have 30 Stress Tensors. Cauchy Stress Tensor is a 3x3 matrix. In Matlab, it is converted to a column vector. Each column of the file named "Cauchy.mat" represents the Cauchy Stress Tensor. We need to reshape it to make it a 3x3 matrix.
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Without the MATLAB code, the process can also be run by "app.exe". In this case, we have to make sure that "param.txt" and "Input_ODF.txt" files along with other necessary files are available in the folder.
In Simulator folder 5 param files are given for tension/compression, plane strain compression, xy, xz and yz shear forces. For example, we want to run the process for tension then we need to name "param_tension/compression.txt." as "param.txt".
In order to load the neccesary files and to add permission for wine, run the commands on Unix-like operating systems:
cd ../wine-dirs/wine64-build/nls/
make
cd ../wine-dirs/wine64-build/server/
chmod +x wineserver
In order to set the directory of wine copy and paste the command to the bashrc. file:
export PATH=$PATH:./wine-dirs/wine64-build/loader
To run the process in process.m and execute the command for running the simulation, you can use the following code after setting the current directory as "./Simulator":
system("wine app.exe"); % Command for process runningThis command will execute the app.exe file using Wine, which is a compatibility layer for running Windows applications on Unix-like operating systems.
The provided code is a command that runs an executable file called app.exe inside MATLAB. Let's break it down step by step:
matlab -nodisplay -nosplash -nodesktop -r "run('process.m');exit;
matlab: This is the command that launches MATLAB, the programming environment for numerical computing and data analysis.
-nodisplay: This flag tells MATLAB not to display the graphical user interface (GUI). It is useful when running MATLAB in a non-interactive mode, such as in a script or a command line.
-nosplash: This flag prevents MATLAB from displaying the splash screen when it starts up. The splash screen is the initial loading screen that shows the MATLAB logo and version information.
-nodesktop: This flag prevents MATLAB from opening the desktop environment, which includes the Command Window, Editor, and other interactive tools. It is commonly used when running MATLAB in a non-interactive mode.
-r "run('process.m');exit;": This is a MATLAB command that is executed after MATLAB starts up. It consists of two parts:
run('process.m'): This command runs the MATLAB script file process.m located in the Simulator directory. The run function executes the specified script file within the MATLAB environment.
exit;: This command tells MATLAB to exit after executing the script. It ensures that MATLAB closes automatically once the script has finished running.
Overall, this code launches MATLAB in a non-interactive mode, runs the process.m script, and then exits MATLAB. It is commonly used to automate the execution of MATLAB scripts or to run MATLAB code from external programs or scripts.
Md Maruf Billah, Muhammed Nur Talha Kilic, Md Mahmudul Hasan, Zekeriya Ender Eger, Yuwei Yao, Kewei Wang, Alok Choudhary, Ankit Agrawal, Veera Sundararaghavan, Pinar Acar, "MicroProcSim: A software for simulation of microstructure evolution", Manuscript in preparation.
email: [email protected], [email protected]
Copyright (C) 2024, Virginia Tech, University of Michigan, Northwestern University.
See COPYRIGHT notice in top-level directory.
This research was supported by the National Science Foundation (NSF) CMMI Division Grant CMMI-2053840/2053929. Partial support from NIST award 70NANB19H005 and Northwestern Center for Nanocombinatorics is also acknowledged.