[PSUBS-MAILIST] bolt in penetration

Sean T. Stevenson via Personal_Submersibles personal_submersibles at psubs.org
Sat Jan 10 14:16:22 EST 2015


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. 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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