Menu

Discussion Forum

New Discussion
Filtrer

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 The information provided may be out of date.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.

Force calculation gives N instead of N/m

Posted 21 juil. 2013, 02:56 UTC−4 Low-Frequency Electromagnetics, MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3a 3 Replies

dnh37
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi,

I draw two beams next to each other in cross-section (a 2D simulation) and apply 1V to one and 0V to the other, and solve for electric field. When I do a Force Calculation in COMSOL v4.3a for beam #1 I get 1.3e-11 N. When I do a force calculation for beam#2 I get the same number in negative form as I'd expect by symmetry. When I do a force calculation for a box containing both beams I get something near zero, as I'd expect. See attached file.

However my problem is, I was expecting to get a force-per-meter [N/m, not N]. Because integrating the stress tensor for such a 2D simulation should give force-per-meter, and then when you go to do a 3D simulation you apply that force-per-meter at each point along the z-dimension of the beam.

What is going wrong?

Thanks,
David
3 Replies Last Post 22 juil. 2013, 02:58 UTC−4
Jens Krause
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22 juil. 2013, 02:52 UTC−4
Hallo David,

the is a setting that specifies the thickness in the 3rd dimension and
force calculation are multiplied with this value. So instead of N/m
you get N.

Regards

Jens
Hallo David, the is a setting that specifies the thickness in the 3rd dimension and force calculation are multiplied with this value. So instead of N/m you get N. Regards Jens
dnh37
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22 juil. 2013, 02:57 UTC−4
Thanks. Where is this? I'm clicking around but can't see that anywhere.
Thanks. Where is this? I'm clicking around but can't see that anywhere.
dnh37
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22 juil. 2013, 02:58 UTC−4
Never mind, it's under Solid Mechanics node (or whatever type of simulation you choose).
Never mind, it's under Solid Mechanics node (or whatever type of simulation you choose).

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