Bolts in Shear on Circumferential Bolt Pattern

[sleepdrifter]

I'm designing a part that will attach to a circumferential bolt pattern, with threaded holes on the mating component. In my attached picture below, the blue components is my part that will have thru holes, the orange component is the mating component with threaded holes, and the grey component will be shims I use to occupy the .020" gap I'm leaving to put the joint into friction. The mated assembly will be sealed and pressurized to 15 psi.

My primary question is, can I just use a simple bolted joint shear calculation on this? I was referencing Bolted Joint Analysis 4th addition, section 19 for joints loaded in shear. And using a grade 8 3/8-24 fastener and the pressurized diameter being 10.7 inches, I got a decimal when solving for the number of bolts I needed to withstand a force of 1348.8 lbf. I know it's not a massive force but I feel that my calculations are off. Can someone help point me in the right direction of how I can solve for number of bolts needed considering my joint? I believe I oversimplified the calculations.

 

[Stress_Eng]

You could view the FBD as something like this. Pb is the bolt tension load, keeping the two parts together, and Pa1 or Pa2 will be the abutment load, causing the prying load. Obviously there's internal pressure. The shear is due to the differential pressure load. There's bolt bending and there's the reactions at the free ends of the horizontal sections that have been cut vertically.

 

[mfgenggear]

You could view the FBD as something like this. Pb is the bolt tension load, keeping the two parts together, and Pa1 or Pa2 will be the abutment load, causing the prying load. Obviously there's internal pressure. The shear is due to the differential pressure load. There's bolt bending and there's the reactions at the free ends of the horizontal sections that have been cut vertically.

View attachment 8392

Just viewing parts are circular, bearing face is not making full contact as I posted before hand. Not making full contact thus reduced friction

 

[dik]

Is this of any use? I can post the SMath program if you like. I had a project a two decades back for some VOC stacks for a major auto manufacturer in Windsor. The stack had viton gaskets. The manager deleted the gaskets because of all the high strength bolts he thought the joint would be OK. It was low pressure, but the joints leaked.