Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Assigning Materials

Posted Jan 25, 2013, 4:58 a.m. EST Fluid & Heat, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD), Geometry Version 4.3a 6 Replies

Nithin
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

While assigning materials to some solids in my model, I am getting a red cross below the material name in Model Builder. What does that mean? What changes should I do to use those materials for the analysis??
6 Replies Last Post Jan 26, 2013, 10:18 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 25, 2013, 6:47 p.m. EST
Hi
Normally the red cros means that some material properties, expected by the physics seleted, are missing, but sometimes, it can also be red because the material is not yet set into the correct physics mode

An example: NITF conjugated heat flow with solid and fluid domains: by default COMSOL is se up for "solids", and no fluids domains are selected, if you add some metal and some wate rmaterial, COMSOL is still assuming that the physics are for all solid materials, but in the water material definitions you do not have Young modulus, Poisson etc, as these have no meaning for a fluid. The red cross will disappear from the moment you select the default NITF Fluid node and define that the water domain is a fluid, then the red cross are gone)
So, if your physics is set up correctly and the red cross is still there => check carefully the maerial properties missing, either you knw what to define, or it looks like some non-sens, then check your domain and BC selections and search for the error

--
Good luck
Ivar
Hi Normally the red cros means that some material properties, expected by the physics seleted, are missing, but sometimes, it can also be red because the material is not yet set into the correct physics mode An example: NITF conjugated heat flow with solid and fluid domains: by default COMSOL is se up for "solids", and no fluids domains are selected, if you add some metal and some wate rmaterial, COMSOL is still assuming that the physics are for all solid materials, but in the water material definitions you do not have Young modulus, Poisson etc, as these have no meaning for a fluid. The red cross will disappear from the moment you select the default NITF Fluid node and define that the water domain is a fluid, then the red cross are gone) So, if your physics is set up correctly and the red cross is still there => check carefully the maerial properties missing, either you knw what to define, or it looks like some non-sens, then check your domain and BC selections and search for the error -- Good luck Ivar
Nithin
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 25, 2013, 9:47 p.m. EST

Hi
Normally the red cros means that some material properties, expected by the physics seleted, are missing, but sometimes, it can also be red because the material is not yet set into the correct physics mode

An example: NITF conjugated heat flow with solid and fluid domains: by default COMSOL is se up for "solids", and no fluids domains are selected, if you add some metal and some wate rmaterial, COMSOL is still assuming that the physics are for all solid materials, but in the water material definitions you do not have Young modulus, Poisson etc, as these have no meaning for a fluid. The red cross will disappear from the moment you select the default NITF Fluid node and define that the water domain is a fluid, then the red cross are gone)
So, if your physics is set up correctly and the red cross is still there => check carefully the maerial properties missing, either you knw what to define, or it looks like some non-sens, then check your domain and BC selections and search for the error

--
Good luck
Ivar


Thank you for nice explanation sir...

Can I use Brick and Concrete for heat transfer from water flowing through pipes in NITF model?? I can observe that some properties of Brick and Concrete like Dynamic Viscosity, Heat Capacity at Constant Pressure, Ratio of Specific Heats and Thermal Conductivity are not given in the COMSOL material library data. Can I assign t=values of my own for them??
[QUOTE] Hi Normally the red cros means that some material properties, expected by the physics seleted, are missing, but sometimes, it can also be red because the material is not yet set into the correct physics mode An example: NITF conjugated heat flow with solid and fluid domains: by default COMSOL is se up for "solids", and no fluids domains are selected, if you add some metal and some wate rmaterial, COMSOL is still assuming that the physics are for all solid materials, but in the water material definitions you do not have Young modulus, Poisson etc, as these have no meaning for a fluid. The red cross will disappear from the moment you select the default NITF Fluid node and define that the water domain is a fluid, then the red cross are gone) So, if your physics is set up correctly and the red cross is still there => check carefully the maerial properties missing, either you knw what to define, or it looks like some non-sens, then check your domain and BC selections and search for the error -- Good luck Ivar [/QUOTE] Thank you for nice explanation sir... Can I use Brick and Concrete for heat transfer from water flowing through pipes in NITF model?? I can observe that some properties of Brick and Concrete like Dynamic Viscosity, Heat Capacity at Constant Pressure, Ratio of Specific Heats and Thermal Conductivity are not given in the COMSOL material library data. Can I assign t=values of my own for them??
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 26, 2013, 3:02 a.m. EST
Hi

the material dtabase contains common values, if you look carefully you will even find some with T or pA temperature and absolute pressure dependence. The idea is that each users control that these values correspond to the need, partcularly state of the material, as fluid conctrete is certainly much different from solid dried concrete ;)

On some material parameters in the DB you have different states. If you have the maerial library you will fin dozen of similar material in different heat treated states ...

--
Good luck
Ivar
Hi the material dtabase contains common values, if you look carefully you will even find some with T or pA temperature and absolute pressure dependence. The idea is that each users control that these values correspond to the need, partcularly state of the material, as fluid conctrete is certainly much different from solid dried concrete ;) On some material parameters in the DB you have different states. If you have the maerial library you will fin dozen of similar material in different heat treated states ... -- Good luck Ivar
Nithin
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 26, 2013, 4:38 a.m. EST

Hi

the material dtabase contains common values, if you look carefully you will even ind some with T or pA temperature and pressure dependence. The idea is that each users control that these values correspond to the need, partcularly state of the material, as fluid conctrete is certainly much different from solid dried concrete ;)

On some maetrial parameters in the DB you have different states. If you have the maerial library you will fin dozen of similar material in different heat treated states ...

--
Good luck
Ivar


Okay, so can I take it that the values that are left blank for Concrete and Brick can be entered based upon my convenience (As I need the parameters that concern with solid concrete which has set already.) And, the same doubt for brick as with concrete.

Thank You..
[QUOTE] Hi the material dtabase contains common values, if you look carefully you will even ind some with T or pA temperature and pressure dependence. The idea is that each users control that these values correspond to the need, partcularly state of the material, as fluid conctrete is certainly much different from solid dried concrete ;) On some maetrial parameters in the DB you have different states. If you have the maerial library you will fin dozen of similar material in different heat treated states ... -- Good luck Ivar [/QUOTE] Okay, so can I take it that the values that are left blank for Concrete and Brick can be entered based upon my convenience (As I need the parameters that concern with solid concrete which has set already.) And, the same doubt for brick as with concrete. Thank You..
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 26, 2013, 10:14 a.m. EST
Hi
Once the material datab base loaded into your model, you can modify these, add remove at will, you can even ave your materials into your own data base, but check where you save it, if it's in ... user ... /.comsol they might disappear if you upgrade or reinstall COMSOl, as the directory .comsol might be deleted

--
Good luck
Ivar
Hi Once the material datab base loaded into your model, you can modify these, add remove at will, you can even ave your materials into your own data base, but check where you save it, if it's in ... user ... /.comsol they might disappear if you upgrade or reinstall COMSOl, as the directory .comsol might be deleted -- Good luck Ivar
Nithin
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 26, 2013, 10:18 a.m. EST

Hi
Once the material datab base loaded into your model, you can modify these, add remove at will, you can even ave your materials into your own data base, but check where you save it, if it's in ... user ... /.comsol they might disappear if you upgrade or reinstall COMSOl, as the directory .comsol might be deleted

--
Good luck
Ivar


Thank You Ivar...
[QUOTE] Hi Once the material datab base loaded into your model, you can modify these, add remove at will, you can even ave your materials into your own data base, but check where you save it, if it's in ... user ... /.comsol they might disappear if you upgrade or reinstall COMSOl, as the directory .comsol might be deleted -- Good luck Ivar [/QUOTE] Thank You Ivar...

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content