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Irreversible temperature dependence process
Posted 31 juil. 2019, 08:43 UTC−4 General, Modeling Tools & Definitions, Parameters, Variables, & Functions 1 Reply
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Hi,
I want to simulate irreversible thermal process same like phase change but in one direction. For the "phase change" I used alpha parameter which described by tanh (depends on T). however I want the process to be irreversible so when the matiral is heated the material properties will changed according to alpha but when the temp. goes down the materias parameter wouldn't change (not like alpha) How can I write this?
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Hi Ofer,
If I understand what you're trying to accomplish properly, here's something you could do:
- Add a distributed ODE to your model
- Set it up so its dependent variable, let's call it "u", solves the equation du/dt=(T>Tcriterion), with the initial condition u(t=0)=0.
- Having done that, you now have a variable that is equal to 0 unless the temperature has passed Tcriterion at any time in the past and takes a positive value if T has passed Tcriterion, and the boolean (u>eps) is equal to 1 if Tcriterion has been reached and to 0 otherwise and represents a state variable that you can use in your material properties to make them irreversible.
I am sure there is a more elegant solution, but the above should work.
Best,
Jeff
-------------------Jeff Hiller