Hi Jon
You referred to the psubs spread sheet for ribbed
calculations,
I have been playing with this spread sheet and
perhaps you or someone else can, excuse my ignorance, tell me to what the
following changeable colums refer to'
1. n - "no of circumferential lobes for failure
calculation" ?
2. n - "maximum allowable working
pressure?".........(several times under several headings with different values
applied.) also what units?
3. n - "usage factor?"
Also not sure if it is me or the site, but the
activation to the acrobat document site for the "mettalic pressure boundary
components" does not appear to work.
Thank you
Les
----- Original Message -----
Sent: Friday, December 17, 2010 6:24
AM
Subject: Re: [PSUBS-MAILIST] Design
depth
I have not been able to get the latest under-pressure
software to work on my computer, however previous DOS versions did not take
enough factors into account for serious manned or unmanned designs, in my
opinion. It has some use to provide a general idea of some limitations,
however I believe the ABS spreadsheet available from PSUBS takes many more
factors into account and will provide a better design. For thick wall
vessels (no ribs) you can also use the "unstiffened cylinder" calculator on
PSUBS which also is based strictly upon ABS formula.
For PVC, you can
compare the results of the under-pressure program with the information in http://www.us.piping.georgefischer.com/external/us_handbook/03.pdf
What
size PVC where you contemplating using?
Jon
On 12/16/2010 2:24
PM, Daniel Kubiak wrote:
I'm just getting started in this arena, but I came across a nice program
called "Under Pressure" for examing pressure hulls. As a newbie it is
interesting to see how various shapes and materials respond under
pressure. My first project is going to be an unmanned vehicle to
photograph the shipwrecks in the great lakes. I assumed PVC would be
sufficient for this and was shocked to see in Under Pressure that it
would fail at a mere 25 ft (based on the schedule I had planned to
use). I'm not putting life at risk yet, but this saved me
some $$ replacing electonics and really opened my eyes to realize that I
need to KNOW what will and will not work.
Is Under Pressure a
commonly used program? I downloaded it from www.deepsea.com in
the resources section.