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Re: [PSUBS-MAILIST] Pressure Hulls



Hey All,
  I assure you I think highly of you all, HOWEVER,,,,
I will double check ALL math on my sub, I promise. Not
that I don't belive you, just that I don't breath
water, and feel no desire to be smooshed inside a
steel ball. Sounds unpleasant.So you need not worry
that I will kill myself and then blame you. As to the
exact specs for this metal, I am going to try to find
out more today. I am thinking that if I have it tested
for micro damage, then calculate the unreinforced
depth, and use that number even after I DO add
framing, then I wont die. I will also do several
UN-manned pressure tests first.
   Does anyone have any data on Stainless alloys?  As
to windows, who needs'um? They are BIG holes in the
boat, and don't work well with a double hull design.
Cameras can see in more directions, and safer. This
critter is going to be a big ROV, with a little man
living inside at the end of the cable. Or in this
case, a rather large man living inside. It's purpose
is to find, and to work. Not a sight seer. I have not
yet found any formulas for computing reinforcement
strengths. Anybody know how to do this? Where to find
such? Which books are better?

Dewey

*****************************************************
--- Captain Nemo <vulcania@hawaii.rr.com> wrote:
> Hi Ian,
> 
> Interesting formula.  Let me see if I understand it
> with an example, below.
> 
> 
> ----- Original Message -----
> From: "Ian Roxborough" <irox@ix.netcom.com>
> To: <personal_submersibles@psubs.org>
> Sent: Sunday, June 30, 2002 7:53 PM
> Subject: Re: [PSUBS-MAILIST] Pressure Hulls
> 
> 
> > P = 2Ut/R
> > Where:
> >  U = min yield strength
> >  t = hull thinkness
> >  R = outside radius
> 
> 
> Let's say we're talking about something a little
> tougher than mild steel;
> say 0.4% carbon steel ("boiler plate") with a
> Tensile Strength of 44,000
> psi, and a Yield Point of 30,000 psi. Then:
> 
> U = 30,000 psi.
> 
> If we have a 9-foot O.D. sphere of one inch thick
> boiler plate, then:
> 
> T = 1"
> 
> R = 54"
> 
> Then:
> 
> P = 1,111.11 psi
> 
> And if D = P multiplied by 2.245, then:
> 
> D = 2494.444 FSW
> 
> Und Zo...she pops at about 2,500 feet.  Operating
> depth could be, maybe,
> 1,250 FSW ;  830 feet would be even safer.
> 
> I'm asking myself now if I think a 9-foot sphere
> made out of one-inch boiler
> plate could go that deep before imploding. 
> Hmmm....it might.
> 
> Is this how you figure the formula works, Ian?
> 
> BTW: Dewey, I am NOT saying your sphere is suitable
> for this depth; I don't
> know anything about that particular vessel, and
> there could be a lot of
> things about it that might throw the numbers right
> out the door: exact type
> of metal, imperfections in shape or welding, dents,
> corrosion, modifications
> like windows and hatches, etc..  This is just an
> experiment with the
> formula, using assumed variables and metal
> properties.
> 
> Anybody else wanna take a crack at this?  Comments?
> 
> Pat
> 
> 
> 
> 
> 



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