RE: [PSUBS-MAILIST] Horizontal Pressure Hull Weldment Supports?

Brent,

I suspect there is no argument that could be made to suggest adding the horizontal frame members would be detrimental. The consideration to be made however is whether the work involved in constructing/installing such additional members are necessary (or justified) to acheive satisfactory safety margins for a given hull thickness and dimensions/span of circular support bands required to reach a particular maximum depth. I imagine it would be at least theoretically possible for example, to build a frame with circular/horizontal members so close together that you could reach 300 feet in a sub using 14 guage sheet metal as the hull material. Would that be more cost effective than using a 1/4" hull with circular supports every 12 inches? Probably not.

Jon

-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]On Behalf Of Brent Hartwig
Sent: Monday, January 08, 2007 12:05 AM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Horizontal Pressure Hull Weldment Supports?

Horizontal Pressure Hull Weldment Supports?

I've been working on some design ideas for pressure hull structures and in regards to the support system for the outer pressure hull skin I've added horizontal support between the support rings. When it comes to support rings I've seen rolled I-beam styles like on Euronaut, L beam style like you see allot on old navy subs, T-beam style like you see on the new UC-3 and Persistence, and solid metal stock like you see in Kraka. Which is good but I always wondered why I never saw any large number or horizontal supports going between the support rings made out of the same type of material as the rings. I did see one piece added to the Euronaut but I'm not sure what it was for. Likely to attach some equipment.

These weldments would help support the edges of the interior parts of the rings from the the ribboning effect I-beams get when they start to fail. Also the area between the rings is not supported from crushing like a crease in a empty aluminum pop can when you start to squeeze it in the middle. I was thinking that if they are supported you could get a higher depth rating on the sub and if the sub hits something really hard and dents it badly you would have a better chance of being safe.

As far as crush depth calculations I don't know if there are any easy way or hard way to do them with this design.

Ok so enough with typing

Here are some pics of three different support systems for the outer skin I built in Solidworks CAD.