Simply supported circular membrane and stresses

General
1

(dolfin version: 2019.1.0)
Hi,
I’m trying to recreate this plate:

https://fenics-shells.readthedocs.io/en/latest/demo/reissner-mindlin-simply-supported/demo_reissner-mindlin-simply-supported.py.html

however I want to make this circular, and I am not sure how the “left, right, bottom, top” boundary conditions apply here.
Moreover I am trying to get the resulting stresses in the membrane, but I have no idea how to do it. I did follow this thread with a similar topic (Plot Von Mises stress for Simply supported Reissner-Mindlin plate), but couldn’t figure it out.

Can you help me?
Thanks!