prying forces on bolt circle

[drabbag]

I have a pressure vessel with a 6 hole bolt pattern holding an end cap to the vessel. I have calculated direct tension on the bolts due to the pressure on the end cap. That was fairly simple. I also need to calculate forces on the bolts created by the prying effect of the pressure on the end cap, as well as any shear forces on the bolts due to the radial deflection of the end cap.

Prying force - is there an easy (or not so easy) formula for performing this calculation? Is it as simple as looking at the moment caused by the pressure on the 60 degrees of the circular plate that would be taken by the each bolt?

Shear force on bolts - can I look at radial stresses or strains in the plate, and assume that the bolts will see these strains?

I have looked through various stress analysis books and haven't found anything appropriate.

Thanks.

Steve

 

[Fabrico]

Symmetry and bolt tension would be major considerations. Attention should focus on prevention of any prying force, because if there is one, it's probably too late.

 

[CoryPad]

Prying force is not so easy. VDI 2230 Systematic calculation of high duty bolted joints covers calculation of this, and can be obtained from Beuth:

http://www.beuth.de/cmd;jsessionid=...2BB065.3?level=tpl-Suchergebnis&languageid=en

Regards,

Cory

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