Re: [PSUBS-MAILIST] acrylic cylinder

["Sean T. Stevenson" <cast55@telus.net>]

OK - I can understand the confusion, as Figure 13.15 puts a lot of information 
in one diagram.  The each plotted curve corresponds to a t/D value, indicated 
by a text label beneath each plot.  Each plot is a series of joined arcs, with 
each curved segment corresponding to a particular number of lobes expected 
during failure.  These are the text labels above each plot - omitted on a few 
of the lower ones because the text would be too dense, but you can count in 
from the edges.

The X coordinate is L/D as you surmised, but the Y coordinate is not pressure 
- at least, not directly.  Actually, using your L/D value, look up to the 
appropriate t/D plot (where you will find the number of lobes expected at 
failure) and then read across to the Y axis, to get a value of "eta" used in 
the following equation:

Pc = eta * 0.035  
(Pc = eta * E * 10^-7 for non-acrylic material)

Where Pc is the short term critical pressure in psi.

Three separate plots are presented, but you can think of these as simply 
stacking on top of one another.  The plot is log-log, showing two orders of 
magnitude in X and six in Y.

-Sean


On July 12, 2009 19:40:36 Jon Wallace wrote:
> Can anyone help me decipher Figure 13.15, page 752, 753, in Handbook of
> Acrylics?  The X coordinate is L/D, the Y coordinate is supposed to be
> pressure.  But I don't understand what the plotted numbers are supposed
> to be representing.  I understand each plot line represents a t/D value,
> but not what the plot point is representing.
>
> Also, am I correct that  Y = 1000 = 35psi ?
>
> Thanks,
> Jon




************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.

PSUBS.ORG
PO Box 53
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************