Reply To: Stress Singularity Appearing at Location of Anticipated Max Stress

[jvaldes]

mohan,

For the first case, the back side of the component is the same geometry as the front. The main difference is that there is no pressure applied to the back side as it is isolated by the o-ring grooves. (Obviously there are o-ring grooves on the front side as well. This analysis is for a worst-case condition where only one side is pressurized. The o-ring grooves on the front are for a different, less conservative, mounting configuration which would isolate out the front from pressure as well.) The back side is also constrained like the front: "Compression Only Support C" is applied to the back of the shoulder in the same way you see it applied in figure 1 from the original post. I used the compression only as it's a more realistic constraint for this application (see figure 1 here). That being said, I can’t use the full coverage support you show in your second setup, I can only hold a rim rather than the whole back side, basically an annulus with Ø2.8 OD and Ø2.7 ID.

Also here are a series of hopefully clearer pictures outlining the stress. The green “line” of stress there (seen clearest in figures 4 and 5) that makes it’s way around the shoulder is the ID of that annulus and is a singularity all the way around at the edge of the compression only boundary condition.