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Parameter optimization for biphasic confined compression stress-relaxation
Only the model file (CCsrlxFit.feb) can be imported into PreView. The optimization file (CCsrlxOpt.feb), which is created manually, should be opened in a text editor.
Thanks for the speedy response. I have tried to run the optimization file from the command line, and I am getting an error message (Error message attached). The other file is running okay. Am I doing something wrong here ? OPT_Error.jpgAre there steps I am missing or something I am not doing correctly. My aim is to run your files first and then start working on my own model and experimental data
I am getting the following error when I try to run the optimization file (FATAL ERROR: failed openning input file CCsrlxFit.feb). I have checked the file name and its correct and the CCsrlxFit model file run okay by its self. I was wondering if its a matter of running the wrong FEBio version. As stated on my previous discussion I have viscoelastic compressive experimental data that I want to see to simulate using the bi phasic method Untitled.jpg
2nd question is: Do we have an FEBio biphasic model that I can use for transversely isotropic viscoelastic tissue properties. I have experimental data obtained when the load is applied with the muscle fibres oriented at the following angles 0, 15, 30, 45, 60, 75 and 90 degrees.
Thanks
Michael
Last edited by takazam; 06-04-2013, 03:39 AM.
Reason: Correcting the format
If you run the optimization file from a folder other than where it resides you must include the full path to the model filename in the optimization file.
I am trying to run optimization for a tension test using a biphasic model. Neo-Hookean viscoelastic was chosen for the solid phase.
The first 10 points in the load curve are related to constant strain rate ramp and proceeding points are showing relaxation. While the optimization is running, in all iterations, when I compared the current column with required column, I saw that the load in the current column is increasing in the first 12 points. It seems that there is an inconsistency between the FEBio file and loadcurve in terms of time. I checked FEBio file and the time for prescribed displacement is the same as ramp time in the load curve data.
I would like to know if there is an explanation for it.
To help you understand the problem better, I have attached the FEBio file and Optimization file. Tension.febOp.feb
You did not use must points in your Tension.feb file. This means that FEBio will not necessarily pass through the time point corresponding to the end of the ramp displacement (t=18 s according to your Op.feb file). That's why you are getting this problem.
To run this example in FEBio2, use CCsrlxFit2.feb for the model file and CCsrlxOpt2.feb for the optimization file. Use the following command to run the optimization:
I am doing Optimisation on viscoelastic and hyperelastic material coefficients by simulating indentation test. By doing the optimisation, I got some coefficients, but the force-deformation graph using optimised values, have some positive loads which means tension. These positive values have effects on objective function and may change my final results.
I thought may be not a bad idea to change these positive values to zero, however I couldn't find any way to do it. Do you have any suggestion about this problem?
When using solid mixtures, you need to assign a name to each mixture component, then use that name in the optimization file. For example, in the model file,
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