Effacer les filtres
Effacer les filtres

Use of Fmincon for stress relax data

21 vues (au cours des 30 derniers jours)
DAVIDE MEULLI le 30 Mai 2024 à 9:49
Commenté : Mathieu NOE le 30 Mai 2024 à 10:11
I have to use "fmincon" to solve the optimization problem for the fitting of an "Stress Relaxation" curve. My aim is to define the coefficient of the Prony Series (gamma_i & tau_i).
The problem is that i don't know how to define my function and start the fitting in order to find e1,e2,e3 & tau1,tau2,tau3.
In Input i have the experimental data (stress relax) and time
fun= E0 * (1 - ( (e1*(1-exp(-t/tau1))) + (e2*(1-exp(-t/tau2))) + (e3*(1-exp(-t/tau3)))))

Réponses (1)

Torsten le 30 Mai 2024 à 10:09
Modifié(e) : Torsten le 30 Mai 2024 à 10:11
I suggest you read the examples for the different suitable solvers. They will show you exactly how to proceed for your case.
Maybe it's better to use a solver especially designed for parameter fitting than fmincon:
fitnlm, fit, lsqcurvefit from the curve-fitting toolbox or fminspleas from the file exchange.

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