[PSUBS-MAILIST] bolt in penetration

[Sean T. Stevenson via Personal_Submersibles]

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 shell
> 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 inboard 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 hull.
> Hank
> 
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