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.

Using the variables u and v in the function describing applied force

Please login with a confirmed email address before reporting spam

We’re working on a Mechanics problem where we would like to use the variables u, v, w, (displacements in x, y, and z) in the description of applied force. This is an iterative problem--as v decreases, the force increases, until it reaches either a steady state solution, or a "Snap"--the problem runs away, meaning v continuously increases and never converges on a point. We were able to put v in the force formula. It seemed like COMSOL accepted the variable. And initially we thought that the solver was actually doing the iterations for us. But further investigation made us question this hypothesis. Can you please shed some light on this question? Attached is a screenshot showing our setup.

-------------------
Khurram Tai


1 Reply Last Post Aug 15, 2022, 4:39 a.m. EDT
Henrik Sönnerlind COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 2 years ago Aug 15, 2022, 4:39 a.m. EDT

This looks like a correct type of expression for the force. It will generate a nonlinear formulation. The study step as such should, of course, also be geometrically nonlinear.

-------------------
Henrik Sönnerlind
COMSOL
This looks like a correct type of expression for the force. It will generate a nonlinear formulation. The study step as such should, of course, also be geometrically nonlinear.

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.