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.

Cad File Import in comsol 4.0a

Please login with a confirmed email address before reporting spam

Hi,

I'm using comsol 4.0a and it seems that it can only import parasolid cad file type. All other importable file type such as (*.iges, *.step, *sldprt and etc) runs into problem. It keeps telling me ' no such feature exist". Does it mean that my license does not include this feature. I have no problem with this with my comsol 3.5a software. Anyone has this problem ?

By the way, I notice that comsol cannot analyse coupled solid-shell structure problem using structural module. Any experts out here that are able to model solid-shell structure in comsol environment. Your advice is very much appreciated.

5 Replies Last Post 16.11.2010, 15:34 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 15.11.2010, 14:50 GMT-5
Hi

For me with a CAD import and SolidWorks Livelink, I can read in 3D Solidworks, Parasolid, STEP, and IGES files. For 2D its limited to dxf. But 3D dxf is read in X-Y format.

However you must be sure you save the correct entities to in the CAD files, as these files can contain only volumes, or surfaces or only lines, or a mixture, and COMSOL cannot always reconstruct solids form simple lines, without help. YOu have a few options on the CAD file save side, as well on the COMSOL side. Finally the repair tolerance must be set accordingly to allow small features i these are wanted or needed.

Now concerning mixing Solids and shell, beams or trusses, you have already a few threads thereon in the FORUM, try a search. Basically you must ensure that you link these correctly, as solids have no rotational degrees of freedom defined by default, and the other three have rotations defined. Furthermore, there seem to be a issue on the material definitions. You should not use the same material for 3D and for 2D physics, rather duplicate the materials and use them separately for 3D solids and the other for the 2D. Apart from this workaround it'e OK for me

--
Good luck
Ivar
Hi For me with a CAD import and SolidWorks Livelink, I can read in 3D Solidworks, Parasolid, STEP, and IGES files. For 2D its limited to dxf. But 3D dxf is read in X-Y format. However you must be sure you save the correct entities to in the CAD files, as these files can contain only volumes, or surfaces or only lines, or a mixture, and COMSOL cannot always reconstruct solids form simple lines, without help. YOu have a few options on the CAD file save side, as well on the COMSOL side. Finally the repair tolerance must be set accordingly to allow small features i these are wanted or needed. Now concerning mixing Solids and shell, beams or trusses, you have already a few threads thereon in the FORUM, try a search. Basically you must ensure that you link these correctly, as solids have no rotational degrees of freedom defined by default, and the other three have rotations defined. Furthermore, there seem to be a issue on the material definitions. You should not use the same material for 3D and for 2D physics, rather duplicate the materials and use them separately for 3D solids and the other for the 2D. Apart from this workaround it'e OK for me -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.11.2010, 03:27 GMT-5
Hi Ivar,

Thanks for replying. I have tried to search for related threads on coupling solid and shell structure. But there is no explicit example to teach one how to tie the two physics together. I would be grateful if by any chance you could provide a very simple example file of how to tie these two together. I'm rather new to comsol.


For the cad import module, I just cannot import any other file type except parasolid file format. It keeps saying 'licensing errro -5 no such feature exists in cadreader'. Maybe I have to contact support to find out whether there is anything wrong with my license. It does'nt happen on 3,5a and 4.0.

thanks in advance.
Hi Ivar, Thanks for replying. I have tried to search for related threads on coupling solid and shell structure. But there is no explicit example to teach one how to tie the two physics together. I would be grateful if by any chance you could provide a very simple example file of how to tie these two together. I'm rather new to comsol. For the cad import module, I just cannot import any other file type except parasolid file format. It keeps saying 'licensing errro -5 no such feature exists in cadreader'. Maybe I have to contact support to find out whether there is anything wrong with my license. It does'nt happen on 3,5a and 4.0. thanks in advance.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.11.2010, 09:47 GMT-5
Hi

I can only indeed suggest to contact support for such versioning issues, I'll try to reply further on the mixing solid-beam issue, but I need a day or two, sorry slightly skeezed these days ;)

--
Good luck
Ivar
Hi I can only indeed suggest to contact support for such versioning issues, I'll try to reply further on the mixing solid-beam issue, but I need a day or two, sorry slightly skeezed these days ;) -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.11.2010, 13:28 GMT-5
Thanks Ivar,

Look forward to your reply soon.
Thanks Ivar, Look forward to your reply soon.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.11.2010, 15:34 GMT-5
Hi,
to start with

The main issue is to link the beam angles "thx, thy, thz" to the solid that has no default angular dependent variables. I nomally use the curl of the displacement field, that is valid for solid small deformation (small angles up to some degrees) i.e. (if I remember right)

Thx = 0.5[rad]*(wY-vZ)
Thy = -0.5[rad]*(wX-uZ)
Thz = 0.5[rad]*(vX-uY)

pls check the sign carefully, I easily mix them up ;)

These angles defined on the interface (or an average of a boundary interfacing the beam) are to be used as prescribed displacement for the Beam physics on the interface.

This links the solid to the beam, but you need the other direction too, this you can get via a weak constrsaint, but I do not rememnber the correct formula, have to find it back ;)

I wounder if there is not some examples on the model exchange ?

Thest this out on a simple case that you know or can esily check analytically, you will soon catch the trick
--
Good luck
Ivar
Hi, to start with The main issue is to link the beam angles "thx, thy, thz" to the solid that has no default angular dependent variables. I nomally use the curl of the displacement field, that is valid for solid small deformation (small angles up to some degrees) i.e. (if I remember right) Thx = 0.5[rad]*(wY-vZ) Thy = -0.5[rad]*(wX-uZ) Thz = 0.5[rad]*(vX-uY) pls check the sign carefully, I easily mix them up ;) These angles defined on the interface (or an average of a boundary interfacing the beam) are to be used as prescribed displacement for the Beam physics on the interface. This links the solid to the beam, but you need the other direction too, this you can get via a weak constrsaint, but I do not rememnber the correct formula, have to find it back ;) I wounder if there is not some examples on the model exchange ? Thest this out on a simple case that you know or can esily check analytically, you will soon catch the trick -- Good luck 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.