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 The information provided may be out of date.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 Jul 21, 2013, 2:56 AM EDT AC/DC & Electromagnetics, MEMS & Nanotechnology, MEMS & Nanotechnology, Modeling Tools, Parameters, Variables, & Functions Version 4.3a 3 Replies
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?