Re: [PSUBS-MAILIST] In my search for a simple, cheap pressure hull ...

[AndrePevestorf@aol.com]

In a message dated Tue, 6 Nov 2001  8:52:25 PM Eastern Standard Time, Ian Roxborough <irox@ix.netcom.com> writes:

> 
> Hi all,
> 
> I've thinking along the GRP lines for a while.
> Thought I'd pass along some information, mainly
> the material definition of GRP so any body using
> Alec Smyth's useful little spreadsheet can compare
> GRP to steel.
> 
> Material definition for GRP (fiberglass matting):
> 
> E = Young's Modulus : 65GPa or 9427121 psi
> Poisson's Ratio : 0.35
> Yield Stress : 1200MPa or 174039 psi

Hi,

are You sure? In my opinion the tensile strength is about 120 - 320 MPa ... can GRP realy yield...???

regards,  André


> Density : 2.1 g/cm^3 or 0.06387 lbs/in3
> 
> The above data is from the book "Pressure Vessels
> external pressure technology" by Carl T. F. Ross.
> 
> I think testing many vessels to collapse depth is
> key before trusting your life to a GRP based pressure
> vessel.
> 
> Somebody meantioned using a cardboard tube as the
> frame for constructing a GRP pressure vessel.  Another
> more durable and maybe more useful method would be
> to use a section of large diameter corrugated polyethylene
> (or other plastic or GRP) piping, similar to piping
> used for drains in some areas.  Done correctly, the
> corrugations will form GRP hoops giving greater strength
> to the pressure vessel (the same as steel hoops on a metal
> pressure vessel).
> 
> I'm hoping to start destructively testing some
> smaller GRP pressure vessels some time next year.
> If we share our test results we should be able to
> plot some nice curves and accurately compare the
> practical results to the math side of things.
> 
> I'll also post a bio at some point as well.
> 
> Ian.
> 
> On Wed, 7 Nov 2001 07:37:52 +1000
> "Walter Starck" <wstarck@ozemail.com.au> wrote:
> 
> > Phil,
> > 
> > It would seem a fairly simple thing to lay up a series of small
> > composite vessels and test to collapse depth to get some idea of
> > variability and relative strength of  various resins, fibers, and
> > laminates.  Do you know if this has been done and if so are the results
> > accessible?
> > 
> > Walter Starck
> > Golden Dolphin Video CD Magazine
> > of  diving and underwater photography
> > www.goldendolphin.com
> > 
> 
> -- 
> Stop killing everything.