[PSUBS-MAILIST] bolt in penetration

[hank pronk via Personal_Submersibles]

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. Brian
  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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