How to extract the force on a hole boundary?

1

hi everyone,

this is a displacement controlled problem. right hole if fixed and left hole is applied a delta-u step by step. I want to calculate the traction on the left hole.

image
image1121×622 13.3 KB

thanks in advance

2

Hi, I covered this recently here https://comet-fenics.readthedocs.io/en/latest/demo/tips_and_tricks/computing_reactions.html

2 Likes
3

Thanks a lot. it works!

4

Hello bleyerj,
Thank you for your valuable link. Your link explained how to calculate the force on a Dirichlet boundary (the left clamped boundary in the link). But if the Dirichlet boundary is imposed on a point, do you know how to calculate the force on it? Thank you very much in advance.

5

It works exactly the same using the work of internal forces.
You cannot do it with the first method using the postprocessed stress since the stress at a given point is not well defined. You could project it on a suitable function space but this will induce a lot of errors, unwanted averaging, Gibbs phenomenon etc.

6

I understand now. Thank you very much.