[PSUBS-MAILIST] Cold verses Hot rolled Tee rings ?

[Alec Smyth via Personal_Submersibles]

The reason is that per stress calculations what really counts is the moment
of inertia around the intersection of stiffener and shell. That means the
material further from that intersection contributes much more than the
material closer to it. To visualize this intuitively, imagine a stiffener
made by bending a flat bar the "easy way" versus a stiffener that is cut
out of a flat ring and is therefore much deeper. Both rings might weigh the
same, but the one that's bent the easy way and has its center of mass close
to the shell does a whole lot less stiffening than the deep ring of the
same weight. Now taking the same logic further, the most efficient
configuration is a substantial flange that is held well off the shell by a
deep web, even if the web is not very thick.

Best,
Alec

On Tue, Jun 12, 2018 at 5:27 PM, hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Ian,
> Why T rings, it might be cheaper and for sure super accurate to cut rings
> from plate.  You can have rings cut in halves or thirds to save material.
> Gamma has solid rings internal instead of T bars.  Just an option.
> Hank
>
> On Tuesday, June 12, 2018, 3:08:52 PM MDT, Brian Cox via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Ian,
>       What I did was to order vertical and horizontal rings and weld them.
>
> Brian
>
>
>
> --- personal_submersibles at psubs.org wrote:
>
> From: irox via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles at psubs.org
> Subject: [PSUBS-MAILIST] Cold verses Hot rolled Tee rings ?
> Date: Tue, 12 Jun 2018 11:15:52 -0700 (GMT-07:00)
>
>
> Hi sub folks,
>
> for my K250 (VAST MKIII type) resto-mod I'm planning on adding external
> re-enforcing rings.
>
> I recently got a quote for some hot rolled T rings (1-1/2 x 1-1/2 x 1/4 OD
> 39" out-of-round tolerance %1) for ~$800 + shipping.  Since it was the only
> place that replied to my quote request, I'm thinking of going with them.
>
> I know cold rolled is dimensionally more accurate, but is going with hot
> rolled going to cause me issues?
>
> Thanks,
>   Ian.
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