Different Stresses - Counterbore & Foundation Connectors

Hi All,

I have been doing an analysis on a 2 part assembly, which are bolted with each other. In one scenario I am using Standard Counterbore bolt connectors, and in the other I am using Foundation Bolt connectors. Unrealistic high stresses are coming in the Standard Counterbore bolts. Can someone please advise why is this so?

In reality, studs will be used, which will have nuts on either sides of the studs. Thanks in advance.

Regards,

LS

SolidworksSimulation