Re: [PSUBS-MAILIST] Pressure Hulls

[Ian Roxborough <irox@ix.netcom.com>]

On Mon, 1 Jul 2002 01:53:37 -1000
"Captain Nemo" <vulcania@hawaii.rr.com> wrote:

> From: "Ian Roxborough" <irox@ix.netcom.com>
> 
> > P = 2Ut/R
>
> Und Zo...she pops at about 2,500 feet.  Operating depth could be, maybe,
> 1,250 FSW ;  830 feet would be even safer.

> Is this how you figure the formula works, Ian?

Hi Pat,

Yes, you seem to be using it the same way I've used in the past.

Btw, the above formula is for thin-walled spheres only, where the
ratio of t/R > 1/30 (you'd need to use a different formula
for a greater t/R value).

More warnings: This formula is calculating the yield pressure
only, there are  more formulas for calculating the sphere's
"limit pressure".  This involves calculating the "linear
classical buckling pressure".  Calculaing the "limit pressure"
seems to be based on variations of the ratio between
"limit pressure" and "linear classical buckling pressure"

I'm leaving to go camping for a week and probably won't have
time to type out the "limit pressure" and "classical buckling
pressure" formulas until I get back (assuming people are
interested and the formula's are not copyright'd some how,
you can't copyright formula?, right?).

The ABS book is pretty good for give formuli without
"too much math".  It give lots formuli for calculate
pressure limits of cones, different stiffener rings,
end caps (hemisperical, ellipsoidal, torispherical),
out of round/shape, fatigue, etc....

Ian.

-- 
The moon ate the sun on Monday and it was an awsome sight to see.