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RE: [PSUBS-MAILIST] hull thickness
Or to keep it simple, I recall someone once posted the example of an
experiment with a plastic soda bottle. You can put several hundred psi
inside a two liter plastic soda bottle, at which point it'll fail by
blowing off the plastic screw top. But you can tell from how these
bottles scrunch up when you pick them up half full, that they'll
withstand virtually no external pressure at all. You can't draw any
inferences at all from internal pressure performance -- the ability to
withstand external pressure needs to be calculated based on the geometry
and materials specific to your design.
Cheers,
Alec
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Stephen
Pearce
Sent: Monday, October 16, 2006 8:45 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] hull thickness
David
Joe is correct. I had wrongly made the same assumption at the time.
I am not sure where it is in the archive but the string was back in
April/ May this year.
Steve P
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph
Perkel
Sent: Tuesday, 17 October 2006 10:28 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] hull thickness
Hi David,
"100 psi
internally (pipe code spec's) so i would expect it to take the same
externally"
Take care with that, it has been discussed on this forum a number of
times and there are some surprising (but inescapable) reasons why this
is not the case.
I believe Sean Stevenson gave an eloquent engineering dissertation on
precisely this issue. A search of the archives and a bit of background
research on your part will reveal this.
Joe
>From: DrewBane1@aol.com
>Reply-To: personal_submersibles@psubs.org
>To: personal_submersibles@psubs.org
>Subject: [PSUBS-MAILIST] hull thickness
>Date: Mon, 16 Oct 2006 17:41:05 EDT
>
>
>
>It is going to be an ambient pressure sub at first but has the ability
to
>withstand 100 psi
>internally (pipe code spec's) so i would expect it to take the same
>externally
>
>
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