On a free boundary surface of a solid, one of the principal stresses should be zero (plane stress), or equal to the applied pressure, if there is a pressure load on it. This, seemingly simple boundary condition is not always satisfied and apparently not enforced by the solver. I'm currently working on a hydraulic valve with a high internal pressure load. On some internal radii where this pressure is applied, one of the principal stress should be equal to this pressure, according to theory. After having run a singla pass adaptive analysis with default mesh settings, max principal is +1418, min principal is about +200 in the same location, but should be -103 (= applied pressure) according to theory. What does the ptc community suggest? Refine mesh?
So we have some known information about the stress state at the boundary surface. I'm not a programmer, but I imagine it should be possible to enforce this plane stress state on the boundary surface ? Is there any ptc developer in this community who can shed some light on this?
/Best regards Mats Lindqvist, Avalon Innovation Sweden