Henrik Sönnerlind
COMSOL Employee
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Posted:
3 years ago
2021年8月25日 GMT-4 02:53
You can use the multiplication with determinant of the deformation gradient (solid.J) also in your own equations.
This said, having changing densities is always tricky. Is mass conservation to be valid in your calculation domain, or are you losing mass to the surrondings? Note also that the thermal coefficent of expansion in general is not imdependent of density, since it describes the change in volume of a piece of material containg a certain number of molecules.
-------------------
Henrik Sönnerlind
COMSOL
You can use the multiplication with determinant of the deformation gradient (solid.J) also in your own equations.
This said, having changing densities is always tricky. Is mass conservation to be valid in your calculation domain, or are you losing mass to the surrondings? Note also that the thermal coefficent of expansion in general is not imdependent of density, since it describes the change in volume of a piece of material containg a certain number of molecules.
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Posted:
3 years ago
2021年8月25日 GMT-4 03:27
Updated:
3 years ago
2021年8月25日 GMT-4 03:28
Thanks for the fast reply!
I assume you mean the derivative of solid.J? Because thats what i came up with as well (as an absorption coefficient) and it seems to be working.
As I have set it up right now I shouldnt loose any mass but when I integrate all densities over the domain the total mass does change and I dont know why.
The density dependence of the thermal expansion shouldnt be too much of a concern in the model since the pointwise transitions happen relatively fast.
Thanks for the fast reply!
I assume you mean the derivative of solid.J? Because thats what i came up with as well (as an absorption coefficient) and it seems to be working.
As I have set it up right now I shouldnt loose any mass but when I integrate all densities over the domain the total mass does change and I dont know why.
The density dependence of the thermal expansion shouldnt be too much of a concern in the model since the pointwise transitions happen relatively fast.