I am trying to simulate a press fit assembly, in which boss amde of PC is press fitted with a threaded insert made of brass. I simulated it using shrink fit connections in solidworks simulation. i find out the hoop stresses and VM stresses.
The insert outer surface has serrations to prevent rotation. at the location of the serration (on inner surface of the boss) i am getting stress values which are far higher than the material break strength of boss. these stresses reduce both circumferentially as well radially outwards and reach values less than the yield stress.
My question is regarding the results interpertation, how can i get stresses at which the crack will initiate on the boss inner surface and propagate to the outer surface.
Physically, the part sometimes develops crack, but most of the part are correct. If the analysis is correct then all the parts should fail in actual.
Please suggest what can be considered as failure stress in this case.
Thanks for your valuable time,