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Re: [PSUBS-MAILIST] endcap/bulkhead question
What about viewports in the endcaps, will they all be looking at the same
spot?
Adam
----- Original Message -----
From: "Ian Roxborough" <irox@ix.netcom.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, December 16, 2003 12:03 PM
Subject: Re: [PSUBS-MAILIST] endcap/bulkhead question
> On Tue, 16 Dec 2003 11:14:26 -0700
> "Adam Lawrence" <adteleka@in-tch.com> wrote:
>
> > The shear stresses are compounded by a v-notch around the root of the
weld.
> > Hydrogen will go to the notch tip increasing the joints susceptibility
to
> > cracking over time from loading and unloading. Reinforcement will help
but
> > interior space and weight are precious commodities.
>
> You build a sub with as much interior space as you need (make cylindered
> longer). If you invert your endcaps you can to save weight by not have
> end-caps so heavy. Also you save displacement (more weight saving here
> as well).
>
> Unless you have hemi-spherical endcaps, they will be the weakest part of
> a pressure hull and will need to be much thicker and heavier than the
> cylinder skin.
>
> The biggest draw back about using the invert end-cap is that I don't
> know of any subs that have tried it.
>
> Ian.
>
> > ----- Original Message -----
> > From: "Ian Roxborough" <irox@ix.netcom.com>
> > To: <personal_submersibles@psubs.org>
> > Sent: Tuesday, December 16, 2003 11:31 AM
> > Subject: Re: [PSUBS-MAILIST] endcap/bulkhead question
> >
> >
> > > On Tue, 16 Dec 2003 10:16:38 -0800
> > > Ian Roxborough <irox@ix.netcom.com> wrote:
> > >
> > > >
> > > > Any additional stress (I'm not sure if there is any), could easy
> > > > taken care of by a heavy frame stiffener/re-enforcing ring.
> > >
> > > Warren you are correct here, where would be extra stress at the
> > > joint of the end-cap and cylinder, but nothing that couldn't be
> > > off set with a heavy stiffener.
> > >
> > > Ian.
> > >
> > > > As for the displacement, it reduces displacement meaning that not
> > > > only have you eliminated most of the risk of end cap buckling, but
> > > > your sub is now lighter. And for useful space inside the sub, that
> > > > is going to depend on how clever you get packing things in.
> > > >
> > > > For people wanting to read more about inverting end-caps on
submarines,
> > > > I would recomend reading "Pressure Vessels, External Pressure
> > > > Technology" by Carl T.F. Ross - Chapter 7 "Novel Pressure Hull
Design"
> > > > (page 280).
> > > >
> > > > Ian.
> > > >
> > > >
> > > > On Tue, 16 Dec 2003 09:15:36 -0800 (PST)
> > > > Warren Greenway <opensourcesub@yahoo.com> wrote:
> > > >
> > > > > The junction between the caps and hull "tube" will be
> > > > > under tremendous stress. There will be shearing forces
> > > > > on the wleds. Also, you are creating less useable
> > > > > interior space for a given displacement. I think those
> > > > > would be some of the basic reasons. Reference Concepts
> > > > > of Submarine Design for more specifics.
> > > > >
> > > > > Warren.
> > > > >
> > > > > --- Emile <2stroke@hetnet.nl> wrote:
> > > > > > Hello all,
> > > > > >
> > > > > > For my future psub I consider an inverted endcap or
> > > > > > bulkhead
> > > > > > See the "drawing"of the pressure part.
> > > > > > ______
> > > > > > )_____(
> > > > > >
> > > > > > At this configuration the sphere shelfs only have a
> > > > > > tension loading what is preferrable.
> > > > > > I lookt at almost every psub design on the site but
> > > > > > no other sub has this configuration, exept for the
> > > > > > Spurdog.
> > > > > > Am I wrong in my toughts and are there high stresses
> > > > > > in the sharp transition from the sphere shelf to the
> > > > > > circular hull??
> > > > > >
> > > > > > hope someboy knows,
> > > > > >
> > > > > > Emile D.L. van Essen
> > > > > > www.AiResearch.nl
> > > > >
> > > > >
> > > > > __________________________________
> > > > > Do you Yahoo!?
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> >