MATLAB Answers


Nonlinear material model fit

Asked by Kálmán Németh on 22 Nov 2019 at 14:01
Latest activity Commented on by Image Analyst
on 23 Nov 2019 at 4:59
Hello there,
I have a few model functions, for example: y=2(x^2-1/x)(C1+C2/x).
I need to fit the parameters for a table of tension test data.Also, i would like to use different error functions, not just least root means square. How can i solve that?
Don't even know how to go about it.


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1 Answer

Answer by Image Analyst
on 22 Nov 2019 at 14:41
 Accepted Answer

fitnlm() is one of my favorite MATLAB functions. See my attached demos where I use fitnlm() to fit a variety of different functions. I think you'll be able to figure out how to make changes. If you can't, then attach some sample data and I'll modify the demo for you.


Kálmán Németh on 22 Nov 2019 at 23:17
Thank you, however i have some questions.
Can i somehow prescribe for the parameters to be positive values or between some value? Also can i modify the error function used in this method?
Image Analyst
on 23 Nov 2019 at 4:59
If you can, I don't know how.

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