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How to know a material's parameter value

Posted Nov 26, 2012, 11:54 a.m. EST Heat Transfer & Phase Change Version 4.2 5 Replies

Roberto Bacchiani
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Hi people,
i have a newbie question:
in my heat transfer simulation i'm using a wood block (kingwood of Comsol material database).
If i look the parameters, the value of density rho is not indicated: how can I see it?
is there a window where i can see the various parameters present in the simulation?

Thank you world!
5 Replies Last Post Dec 4, 2012, 1:49 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 26, 2012, 2:47 p.m. EST
Hi

indeed there is not much in there no young modulus no poisson, density yes, but function of temperature, so you need to define a reference temperature, or to plot out the rho interpolation curve and look up the value around 300[K]

Now I'm not sure what the mu in Pa is exactly ? little explanations in there, perhaps in the doc

In such cases I define a "user material" and search the parameters on the web and fill them in as needed by COMSOL, for HT it's typically k, Cp and rho, but these are often Temperature dependent, hence making the model non linear

--
Good luck
Ivar
Hi indeed there is not much in there no young modulus no poisson, density yes, but function of temperature, so you need to define a reference temperature, or to plot out the rho interpolation curve and look up the value around 300[K] Now I'm not sure what the mu in Pa is exactly ? little explanations in there, perhaps in the doc In such cases I define a "user material" and search the parameters on the web and fill them in as needed by COMSOL, for HT it's typically k, Cp and rho, but these are often Temperature dependent, hence making the model non linear -- Good luck Ivar
Magnus Ringh COMSOL Employee

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Posted: 1 decade ago Nov 27, 2012, 4:01 a.m. EST
Hi,

When you have added a material to your model, you can plot the density rho by going to (for example),

Materials>Kingwood [solid]>Basic>Piecewise 2 (rho), and in its settings window click the Plot button. In the case of Kingwood, the density is a constant value, 1049 kg/m^3, defined in a temperature range from 20 to 30 degrees Celsius (room temperature).

Regarding "mu", it's the storage modulus, which is a material property that is not used in COMSOL. For some materials, the Material Library add-on product includes data also for some properties that are not used in the current version of COMSOL. To get information about a material property in the Material Library, in the Material Library window, click the material of interest (Kingwood, for example). Then select, under Material Properties, the property of interest and click the "Property Information" button. A separate "Property Information" window opens where you find information about the property: a reference and other relevant information about the conditions under which the material property values are valid.

Best regards,
Magnus Ringh, COMSOL
Hi, When you have added a material to your model, you can plot the density rho by going to (for example), Materials>Kingwood [solid]>Basic>Piecewise 2 (rho), and in its settings window click the Plot button. In the case of Kingwood, the density is a constant value, 1049 kg/m^3, defined in a temperature range from 20 to 30 degrees Celsius (room temperature). Regarding "mu", it's the storage modulus, which is a material property that is not used in COMSOL. For some materials, the Material Library add-on product includes data also for some properties that are not used in the current version of COMSOL. To get information about a material property in the Material Library, in the Material Library window, click the material of interest (Kingwood, for example). Then select, under Material Properties, the property of interest and click the "Property Information" button. A separate "Property Information" window opens where you find information about the property: a reference and other relevant information about the conditions under which the material property values are valid. Best regards, Magnus Ringh, COMSOL
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 27, 2012, 5:22 a.m. EST
Hi

Thanks Magnus, I was looking for the definition of the material mu of wood, couldn't find it, just curious ;) but now I know

--
Good luck
Ivar
Hi Thanks Magnus, I was looking for the definition of the material mu of wood, couldn't find it, just curious ;) but now I know -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Nov 27, 2012, 10:16 a.m. EST
Thanks Magnus, that was informative.

Roberto, here is a good reference for thermal and electrical properties of different wood types: www.fs.fed.us/ccrc/topics/urban-forests/docs/physical%20properties%20and%20moisture%20relations%20of%20wood.pdf. There are also good online sources for stress-strain properties if you need them.

Nagi Elabbasi
Veryst Engineering
Thanks Magnus, that was informative. Roberto, here is a good reference for thermal and electrical properties of different wood types: http://www.fs.fed.us/ccrc/topics/urban-forests/docs/physical%20properties%20and%20moisture%20relations%20of%20wood.pdf. There are also good online sources for stress-strain properties if you need them. Nagi Elabbasi Veryst Engineering
Roberto Bacchiani
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Posted: 1 decade ago Dec 4, 2012, 1:49 p.m. EST
I apologize for the delay,
Once again this forum has been great!
Thank you: Ivar, Magnus and Nagi.

Ciao at all!

Roberto.
I apologize for the delay, Once again this forum has been great! Thank you: Ivar, Magnus and Nagi. Ciao at all! Roberto.

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