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Problems with ODE's and equations. Please help
Posted Aug 18, 2010, 3:50 a.m. EDT 0 Replies
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I'm trying to model the porosity of a piece working with general heat transfer, conductive media and axial symmetry strain-stress models with COMSOL 3.5 (a time dependent analysis between 0 a 1 second). I have in paper the model of the porosity, it's a system of ODE'S and scalar expressions. The problem is that I can't manage to write my ecuations into Comsol. I want that it only works in one subdomain (the model has 7 subdomains), this one is heated by Joule effect and it's under pression, with an initial porosity. My intention is to obtain the distribution of the porosity, which depends of time and temperature, in this subdomain. Can somebody help me?
More or lees, this is the function:
y = function of porosity
psi = function of temperature
epsilon (d_e/d_t) = function of "y" and "psi"
porosity (d_theta/d_t) = function of "y" and "epsilon"
I tried constructing the ecuations in the "Subdomain expressions" and "Global equations" for the ODE's, but when it tries to calculate it, it shows the error "Failed to evaluate variable Jacobian". I read and read the help but it there wasn't enough information.
Thanks in advance.
Hello Alejandro Estrada
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