Thin wall enclosure subjected to external pressure

Hello,

I simulates a small thin walled cylinder, closed at both ends.

It is subjected to external pressure.

To have no constraints, I am Loading inertial balance.

I run the simulation, I travel and the stress on the entire piece.

I cut the cylinder in two lengthwise through the axis.

I divide my pressure 2.

In the example of manual Wildfire 2.0 belt buckle.

I place restrictions of symmetry of the cutting face.

I run the simulation, I travel and constraints, but not the same values ​​as before, totally different.

In this case, I only deformation of the cylinder on the edge of the cutting cylinder, but not elsewhere.

For this type of simulation should proceed in a specific manner.

Cordially.

Denis