[PSUBS-MAILIST] External Shapes

[Sean T. Stevenson]

That said, if you are building outside the hull envelope anyway, why not design an optimized hull with external framing? It requires full penetration 100% NDT welding, but is otherwise stronger than an internally stiffened design.

Sean


On April 4, 2014 3:25:16 PM MDT, "Sean T. Stevenson" <cast55 at telus.net> wrote:
>You are likely to run into a problem with total weight, and hence
>carrying capacity. The reason we use stiffeners at all is to create a
>more efficient structure, where the various modes of failure all have
>similar probabilities. Unstiffened cylinders save the additional work
>and welding of a multi-part structure, but have to be comparatively
>thicker to withstand the buckling modes, meaning you have a structure
>which has more strength than is necessary for some modes of failure,
>and consequently is heavier. While you are correct that you can add
>additional superstructure to the outside of the unstiffened cylinder
>without reducing its strength, you might end up having to use the
>superstructure to attach syntactic foam blocks to offset the
>necessarily heavy hull.
>
>Sean
>
>
>On April 4, 2014 12:58:28 PM MDT, Joe Perkel <josephperkel at yahoo.com>
>wrote:
>>Please confirm or rebuke the following train of thought.
>>
>>If one were to use an unsupported cylinder of sufficient sizing for
>the
>>intended design depth,...then that same design is free to use external
>>framing to form an external shape of choice? 
>>
>>Assume uneven spacing of said frames.
>>
>>Joe
>>
>>Sent from my iPhone
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