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RE: [PSUBS-MAILIST] Steel Pipe Hull
Hi
Doug,
I
think we need Cliff Redus to comment.
I
checked your spreadsheet and compared it to mine, and the difference was the
center to center spacing of stiffeners. I left mine at the default value
of 10 inches and you had changed yours to the length of the pipe (I assume)
which is 60 inches. The output doesn't make sense to me either since I
assumed a .0001 stiffener and web was essentially equal to not having a
stiffener. The center to center spacing of stiffeners shouldn't be a
factor in that case. I'm guessing there are some assumptions built into
the formula's behind the spreadsheet geared towards a reasonably sized hull and
it may not be applicable to pre-manufactured small diameter pipes without
stiffeners.
Hopefully Cliff will see this message and take a look
himself.
Jon
Jon
Your right about the stiffeners, but there must be other
problems. Now I get 8 psi :) What are you using for "Center to
center spacing of stiffeners"? When I change it the outcome changes, and
that does not make any sense. Your
calculation can not be right either; 57 psi for a 1/4" think 10 inch
pipe? No Way! I get 57 psi out of a garden hose and I've used 10" steel pipes for temporary colverts and had concrete trucks drive over
them. There is just no way they would not perform to anything less than 1500 feet.
You can download
my sheet from here: http://www.submarineboat.com/sub/BOB2_Hull_Calculation.xls
to have a look if needed.
I really do appreciate this exercise I hope
the outcome is a simpler and more full
proof approach.
--Doug J