Menu

Discussion Forum

New Discussion
Filtrer

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.

Difference between Reaction Force and Total Reaction Force

Posted 17 mai 2021, 12:43 UTC−4 1 Reply

Timothy Russell
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I'm doing a displacement prescribed 3-point bend test (a negative y-displacement is applied at the center of a horizontal beam). I want to determine the reaction force at the point where I've applied the displacement and noticed that solid.RFy is not the same thing as solid.RFtotaly. What is the difference between these terms? solid.RFy seems to give me what I want in this case, but I don't understand what solid.RFtotaly is...

1 Reply Last Post 18 mai 2021, 03:52 UTC−4
Henrik Sönnerlind COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 4 years ago 18 mai 2021, 03:52 UTC−4

solid.RFy is the reaction force to prescribed displacements in the y direction. Actually, it is the same as reacf(v). It has a value in each constrained node, so if you want to see the total reaction force over a certain set of constrained boundaries, you need to do a summation (this is done using an integration operator).

solid.RFytot is the sum of the reaction forces for the whole model. If you are loading by displacement control, it will be zero. If you load by forces, it will equal the total applied loads.

There is, however, one more difference: solid.RFy is only the reaction to pointwise Dirichlet conditions. solid.RFytot includes some other types of reaction forces, for example from elastic supports (Spring Foundation).

-------------------
Henrik Sönnerlind
COMSOL
solid.RFy is the reaction force to prescribed displacements in the y direction. Actually, it is the same as reacf(v). It has a value in each constrained node, so if you want to see the total reaction force over a certain set of constrained boundaries, you need to do a summation (this is done using an integration operator). solid.RFytot is the sum of the reaction forces for the whole model. If you are loading by displacement control, it will be zero. If you load by forces, it will equal the total applied loads. There is, however, one more difference: solid.RFy is only the reaction to pointwise Dirichlet conditions. solid.RFytot includes some other types of reaction forces, for example from elastic supports (Spring Foundation).

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