Crush Calculations for a ball with a hole through it

[ripper1]

I am trying to find some relevent equations for crush factor/stress levels on a ball with a hole through it. It is for a ball valve that will be closed with a rated fluid pressure on one side. Any help would be greatly appreciated.

 

[Cockroach]

I have done this calculation by FEA and compared results to loaded spherical shells. To my knowledge, you will be hard pressed (no pun intended) to obtain closed form equations that exactly mimick your particular case.

Since seat design varies from one manufacturer to the next, the exact hydraulic loading wetted area varies. For example, a Grove B5 twelve inch valve would have different ball stresses than a Nova Peroni of equal size and class. Floating designs have slightly less stress than trunion mounted; however the latter display symetric distribution of stress rather than gradual decreasing patterns between stem and ball bottom as in the former. You can get a multitude of examples in between, Orbit rising stem has different loading because of metal seats and internal seal activation mechanism.

Some advance books in stress mechanics deal with this aspect of the subject. I would start looking at various valve manufacture websites or talk to their engineering manager for particular specifications. Typically this is why consultants are used and get paid for.

Good luck.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada