I think that I uderstand your point now, however still assumption that crack appeard for stress less than yield, for me is just wrong unless it is not a fatigue case byt clear overloading of the strructure. But it's just my opinion.
What I can suggest try to use element CRAC3D, described Here.
I have never used it, but it seems to be answer for your problem with modeling of tiny notches.
As I can see it is suported by NX Nastran Basic Bundle.
Let me know if you will ger reasonable results