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Re: [PSUBS-MAILIST] Hull Shape question
http://www.prismnet.com/~moki/20030215.064209/Endcap4.jpg
http://www.prismnet.com/~moki/20030215.064209/endcap1.jpg
And nothing to say..
best regards Carsten
Cliff Redus schrieb:
>
> Chuck,
> ABS pays allot of attention to the out-of- roundness measurement of
> stiffened cylindrical sections for a reason. Pressure hulls are historically
> cylindrical; why? Because this configuration minimizes the stresses in the
> hull for a give external pressure. If you use the oval hull shape that you
> shown in your folder, the stresses in the smaller radius bends are going to
> be much higher than in the larger radius bends for a given external
> pressure. Since the local maximum stress the hull sees will set the max
> design depth, an oval hull will mean that you will be able to dive to only a
> fraction of the depth of an equivalently stiffened cylindrical section. I
> strongly suggest that before you begin fabrication of an oval hull that you
> have a FE analysis done to determine the maximum operating depth. I think
> you will be surprised at how much design depth you will give away with this
> hull design.
>
> There is a cost penalty you will also pay on fabrication as you will have
> four longitudinal full penetration welds rather than one for the main hull
> section. The cost of fabricating stiffening rings will also be greater
> particularly the flange part of the "T" rings. The web portion of an oval
> stiffener ring is not a problem if you have access to a bed plasma or water
> jet cutter.
>
> I realize that from a design perspective, a cylindrical hull is boring but
> you can always use an FRP shell for a more aesthetically pleasing shape or
> to minimize drag.
>
> Cliff
>
> ----- Original Message -----
> From: "Chuck Will" <chuck@bestan.com>
> To: <personal_submersibles@psubs.org>
> Sent: Thursday, June 30, 2005 10:36 AM
> Subject: RE: [PSUBS-MAILIST] Hull Shape question
>
> > Try this location. Look in the my documents folder.
> > http://f2.pg.briefcase.yahoo.com/bc/aptostechnology@sbcglobal.net
> >
> > How do you post to Moki?
> >
> > Chip
> >
> > -----Original Message-----
> > From: owner-personal_submersibles@psubs.org
> > [mailto:owner-personal_submersibles@psubs.org]On Behalf Of Juergen
> > Guerrero Kommritz
> > Sent: Wednesday, June 29, 2005 10:17 PM
> > To: personal_submersibles@psubs.org
> > Subject: RE: [PSUBS-MAILIST] Hull Shape question
> >
> >
> > Hello Chuck
> > The folder is empty there are no drawings, so it is
> > dificult to discuss about a drawing that is not
> > available.
> > Best wishes
> > Jürgen
> >
> > --- Chuck Will <chuck@bestan.com> wrote:
> >
> >> Adam
> >>
> >> I am still trying to finalize the shape of the hull.
> >> I still would like to
> >> go with an oval hull. The way I am looking at it is
> >> to use two fixed
> >> diameters to create the oval. It will not be a
> >> random oval pattern. It will
> >> be created from a 48" diameter tube and a 16"
> >> diameter tube. The top and
> >> bottom plate will be cut from a 48" diameter tube
> >> cut at the point of
> >> intersection with the 16" diameter side plates. It's
> >> sort of hard to explain
> >> so I made a drawing. I don't know how to post to
> >> Moki so you can link to it
> >> at http://briefcase.yahoo.com/divetruk. Look in the
> >> folder called drawings.
> >> The file name is "Oval Hull Construction". The first
> >> page is 2D and the
> >> second page has a 3D interpretation.
> >>
> >> Basically I am cutting two lengthwise sections of a
> >> large tube and welding
> >> the to two sections of a smaller diameter tube. The
> >> would be extensive
> >> bracing on the interior. I also wondered how I would
> >> do the hull
> >> calculations for strength. Would I use the larger
> >> 48" diameter for all
> >> calculations? Or do I need to do some math to figure
> >> a average diameter? Or
> >> am I still crazy to make my hull oval? It just seems
> >> to fit what I want
> >> better.
> >>
> >> Chip
> >> -----Original Message-----
> >> From: owner-personal_submersibles@psubs.org
> >> [mailto:owner-personal_submersibles@psubs.org]On
> >> Behalf Of Adam Lawrence
> >> Sent: Tuesday, June 07, 2005 5:00 PM
> >> To: personal_submersibles@psubs.org
> >> Subject: Re: [PSUBS-MAILIST] Hull Shape question
> >>
> >>
> >> Hi Chip,
> >>
> >> An oval shaped hull would be as strong as the
> >> largest raduis. So if your
> >> hull is 4 feet wide and 2 feet tall it would be
> >> about equivalent to
> >> calculating the strength of a round hull with a 7
> >> foot radius. But then this
> >> isn't exactly true since you can reinforce the heck
> >> out of it. But to
> >> maximize the weight to opperating depth ratio and
> >> usable inside space, the
> >> solution converges on a round hull with simple ring
> >> stiffners.
> >>
> >> Adam
> >> ----- Original Message -----
> >> From: Chuck Will
> >> To: personal_submersibles@psubs.org
> >> Sent: Tuesday, June 07, 2005 3:48 PM
> >> Subject: [PSUBS-MAILIST] Hull Shape question
> >>
> >>
> >> Hello everyone,
> >>
> >> A quick question on hull shape. I understand
> >> that the best shape for the
> >> pressure hull will be a sphere or a round tube with
> >> braces and with domed
> >> end caps. How much strength is lost with an oval
> >> tube? Imagine pushing down
> >> on a cardboard tube a bit. Flatten it out lengthwise
> >> just a little. It would
> >> have bracing inside as well. Any advice on this?
> >>
> >> Chip
> >>
> >
> >
> >
> >
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