[PSUBS-MAILIST] O2 tanks (via Personal_Submersibles)

[hank pronk via Personal_Submersibles]

Hi Sean,I did a thickness guess and length etc with the Psubs calculator and the scuba tank is good for 4,400 feet. Hank 

    On Sunday, July 2, 2017 11:30 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
 

 I was just going to point this out. You need a fully dynamic / non-linear solver to model behaviour beyond yield, which the companion applets to the CAD packages are not.The standard ABS equations will do fine for design - they are derived from the ASME Boiler and Pressure Vessel Code, Section 8. The greater problem is probably obtaining drawings or accurate measurements of the gas cylinder wall thickness and head geometry.  If you really want externally mounted gas storage for a deep diving sub, you are probably looking at custom vessels anyway. RMS Titanic is on the seafloor at 12,500 fsw. The pressure at that depth is 5700 psi or so - guaranteed to fail even a full SCUBA cylinder at 3000 psi internal.Sean

On July 2, 2017 9:45:01 AM PDT, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
Jerry, Inventor FEA base module is linear model only.  It will only solve one of the three possible failure modes and not either of the buckling modes,  
Cliff 
On Sun, Jul 2, 2017 at 9:19 AM, Jerry Koontz via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Autocad Inventor has the FEA tool built in and works really well.

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Today's Topics:

   1. Re: O2 tanks (via Personal_Submersibles)
   2. Re: O2 tanks (hank pronk via Personal_Submersibles)
   3. Re: O2 tanks (Alan via Personal_Submersibles)


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Message: 1
Date: Sat, 1 Jul 2017 18:59:23 -0500
From: via Personal_Submersibles <personal_submersibles at psubs. org>
To: Personal Submersibles General Discussion
        <personal_submersibles at psubs. org>
Subject: Re: [PSUBS-MAILIST] O2 tanks
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Most of the FEA packages associated with 3-d modeling software use a linear model.  You would need an FEA tool that can model buckling to study this.  An alternative is to use the ABS stress analysis spreadsheet with no stiffeners.  This would give a conserative crush depth.

Cliff


Cliff Redus

> On Jul 1, 2017, at 2:27 PM, Scott Waters via Personal_Submersibles <personal_submersibles at psubs. org> wrote:
>
> I am unsure of the depth rating of an empty scuba tank. It could be easily found out on a solidworks simulation.
> Thanks,
> Scott
>
>
>
> Sent from my U.S. Cellular? Smartphone
>
> -------- Original message --------
> From: hank pronk via Personal_Submersibles <personal_submersibles at psubs. org>
> Date: 7/1/17 12:34 PM (GMT-05:00)
> To: Personal Submersibles General Discussion <personal_submersibles at psubs. org>


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