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 The information provided may be out of date.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.

Beam - Rigid Body

Please login with a confirmed email address before reporting spam

Hi everyone. Is it possible to get a rigid beam?

Thank you for your help.

P.S. I'd like an infinite Young's modulus, not a finite Young's modulus.


4 Replies Last Post 21 dic 2016, 16:15 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: 8 years ago 21 dic 2016, 02:31 GMT-5
Hi

I do not believe that was possible back in old 3.5 days ;)
Today with the newer versions there are the "Rigid Body" domains and the full RBD module to handle this.

--
Good luck
Ivar
Hi I do not believe that was possible back in old 3.5 days ;) Today with the newer versions there are the "Rigid Body" domains and the full RBD module to handle this. -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 21 dic 2016, 03:02 GMT-5
Hi Ivar,

in my university there is only the 3.5a version of Comsol, so I can't use next versions.

Regards,
GA.
Hi Ivar, in my university there is only the 3.5a version of Comsol, so I can't use next versions. Regards, GA.

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: 8 years ago 21 dic 2016, 14:50 GMT-5
Hello

Well back in 3.5 time, I used the trick you just said: turned up the Young modulus, to make my "rigid" parts real stiff.
But do not overdo it, 1000 to 10'000 times is already quite a lot, as else you might get numerical scaling issues. Note that eigenfrequencies scale as sqrt(E/rho) so these increase less than the Young modulus.

--
Good luck
Ivar
Hello Well back in 3.5 time, I used the trick you just said: turned up the Young modulus, to make my "rigid" parts real stiff. But do not overdo it, 1000 to 10'000 times is already quite a lot, as else you might get numerical scaling issues. Note that eigenfrequencies scale as sqrt(E/rho) so these increase less than the Young modulus. -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 21 dic 2016, 16:15 GMT-5
Hi Ivar,

I'd like to avoid the possibility of numerical issues. Is there another way to do it? The bigger Young's modulus, the bigger the possibility of numerical issues.

Thank you very much,
GA.
Hi Ivar, I'd like to avoid the possibility of numerical issues. Is there another way to do it? The bigger Young's modulus, the bigger the possibility of numerical issues. Thank you very much, GA.

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.