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How Comsol proceed to calculate the effective physical property
Posted 4 nov 2010, 07:29 GMT-4 2 Replies
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Hi,
I am using Comsol 3.5 for my Multilayers biological tissues analysis.
I'd like to know how Comsol proceed to calculate the effective physical property (for instance "the relative permittivity") when a tetrahedral (or triangle in 2D) element contains more than one material with different propertie like eps1, eps2, etc. for example.
I had a look at Comsol Multiphysics Guide but I didn't find the response.
Do you have any idea?
Thanks
Hulusi
I am using Comsol 3.5 for my Multilayers biological tissues analysis.
I'd like to know how Comsol proceed to calculate the effective physical property (for instance "the relative permittivity") when a tetrahedral (or triangle in 2D) element contains more than one material with different propertie like eps1, eps2, etc. for example.
I had a look at Comsol Multiphysics Guide but I didn't find the response.
Do you have any idea?
Thanks
Hulusi
2 Replies Last Post 4 nov 2010, 11:04 GMT-4
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Posted:
1 decade ago
Hi Hulusi,
an element is homogenous in its properties. It is member of a specific subdomain with its specific properties.
If your model is made up by an inhomogeneous structure you must either reflect that by the geometry you use or it is up to you to provide COMSOL with averaged properties if this is valid for the physics you are interested in.
An example would be fiber reinforced polymers. You can either model the detailled geometry with the fibers and the polymer matrix modeled as explicit subdomains and their specific properties. Or you set up the composite material as a homogeneous domain with adapted material properties that reflect the composite structure. They will in general then be non-isotropic and non-linear and you must provide it to the program from material specification datasheets or measurements.
Best regards
Edgar
an element is homogenous in its properties. It is member of a specific subdomain with its specific properties.
If your model is made up by an inhomogeneous structure you must either reflect that by the geometry you use or it is up to you to provide COMSOL with averaged properties if this is valid for the physics you are interested in.
An example would be fiber reinforced polymers. You can either model the detailled geometry with the fibers and the polymer matrix modeled as explicit subdomains and their specific properties. Or you set up the composite material as a homogeneous domain with adapted material properties that reflect the composite structure. They will in general then be non-isotropic and non-linear and you must provide it to the program from material specification datasheets or measurements.
Best regards
Edgar
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Posted:
1 decade ago
Dear Edgar,
Thank you for your quick response.
Indeed, we must either reflect the inhomogeneity by the geometry or by providing the average properties. However, in the second case, Comsol do that by itself if we don't specify the average. This is very useful for me who does not want to do an averaging of the physical properties because it could be very tedious. The structure contains more than 20 layers of tissues.
I know that comsol calculate an effective propertiy but I don't know how. What is the purpose of the calculation of this average? The mathematical approach used by Comsol?
Regards
Hulusi
Thank you for your quick response.
Indeed, we must either reflect the inhomogeneity by the geometry or by providing the average properties. However, in the second case, Comsol do that by itself if we don't specify the average. This is very useful for me who does not want to do an averaging of the physical properties because it could be very tedious. The structure contains more than 20 layers of tissues.
I know that comsol calculate an effective propertiy but I don't know how. What is the purpose of the calculation of this average? The mathematical approach used by Comsol?
Regards
Hulusi