[PSUBS-MAILIST] bolt in penetration

Sat Jan 10 14:19:38 EST 2015

Yes but there two of them.
Hank--------------------------------------------
On Sat, 1/10/15, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] bolt in penetration
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Saturday, January 10, 2015, 2:16 PM

 If it is suitable, I presume you're calling
 dibs?
 Sean

 On January 10, 2015
 12:10:14 PM MST, hank pronk via Personal_Submersibles
 <personal_submersibles at psubs.org> wrote:

 Sean,
 I may be able to on Monday.  The sphere was
 owned by a university and we can contact them to find the
 manufacturer.  Given that is was used as a pressure vessel
 paid for by a university working on a government project, I
 have to assume it is good stuff.  Not very scientific but a
 fair assumption at this stage.  Luckily it is right in
 Brian's back yard in California so he was able to look
 at it and might be able to do some detective work.

 Hank
 On Sat, 1/10/15, Sean T. Stevenson via
 Personal_Submersibles
 <personal_submersibles at psubs.org> wrote:

  Subject: Re: [PSUBS-MAILIST]
 bolt in penetration
  To: "Personal
 Submersibles General Discussion"
 <personal_submersibles at psubs.org>

 Received: Saturday, January 10, 2015, 2:02 PM

  Hank, any chance you can
 find out what the alloy
  is? This will have
 a profound effect on its efficacy.
  Sean

  On!
   January
 10, 2015
  11:51:22 AM MST, hank pronk via
 Personal_Submersibles

 <personal_submersibles at psubs.org> wrote:

  Sean, 

 Thank you, that is helpful.  My idea was to

 make the insert as tight as possible (sweat it in)  I am
 not
  sure if the difference in material
 would cause a problem
  though. The idea of
 seating the port into the shell a good

 option also.  I am just chewing the fat here, I have
 enough
  on my plate but it is fun to think
 about.  I was wrong about
  the size, the
 sphere is 6 feet and I wrote 60 in.  I imagine
  that kills the rating quite a bit?
  Hank
  On Sat, 1/10/15,
  Sean T. Stevenson via Personal_Submersibles
  <personal_submersibles at psubs.org>
 wrote:

   Subject: Re:
 [PSUBS-MAILIST]
  bolt in penetration
   To: "Personal

 Submersibles General Discussion"

 <personal_submersibles at psubs.org>

  Received: Saturday, January 10, 2015!
  , 1:40
 PM

   You could certainly
 do that,
  although a three inch
   thick shell is pretty

 substantial - I might consider

 machining
  eg. conical window seats in the
 hull sh!
   ell
   directly,
 and then derating the hull
  to a depth
 whereby the
   actual hull

 thickness is the effective derated thickness
   plus the effective reinforcement, which
 just
  happens to be a

 contiguous shell.  The
  bolt-in arrangement
 would not act as
   hull

 reinforcement though - unless it was a force fit in the
   hole. The idea of reinforcements around
  openings is to
   provide
 material around the
  hole to carry the shell
 hoop
   stresses that
  would
 otherwise have passed through the

  material in the opening, such that you
 don't increase
   the nominal shell
 stress. This requires a
  (relatively)
   smooth load path to redirect

 stress around the hole. Br!
  ian
   recently
  asked me
 about the effectiveness of reinforcements

 like perpendicular flanges lining the hole,

 and this is a
   bit complicated, because
 some
  stress i!
    s
 indeed

  redirected into
 such a flange, but the load is not evenly

 distributed as you move inboar!
   d or
  outboard away from the
   hull
 shell (with
  diminishing returns at
 increasing

  distances),
 and you also introduce a stress concentration
  at
   the perpendicular
 transition. Ideally,
  reinforcements
 should
   be an effective

 thickening of the hull in the region

  immediately adjacent to the opening, tapered
 smoothly
  back
   (something
 like 4:1) into the hull
  shell to provide
 a
   continuous load path

 with no stress concentrations at abrupt

  changes in geometry.
   Sean

   On
 January 10, 2015 8:25:39
 !

 AM MST, hank pronk via Personal_Submersibles
   <personal_submersibles at psubs.org>
  wrote:
   Is it feasible to
 have a
   bolt in penetration in a 3 inch
 thick sphere
  hull.  I am

 picturing machining a hole in
  the hull,
 then inserting a
   window housing
  with a shoulder(flange) that fits tight in

  the hole and is bolted in
 place.  Can that arrangement
  act
   as reinforcement for the hul!
   l.

  Hank

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