This animation shows an o-ring in initial interference with the groove formed in a flanged connection between pipes. The connection is under a bolt preload and one of the bolts is visible in the flange. The element edges are displayed so the interference can be observed.
This is a two step simulation in which the first step represents the assembled state and then the internal operating pressure of the pipe is applied to deform the ring. Some separation between the flanges can be observed. Contact pressure between all of the surfaces is available as well although not shown in this video.