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This might confuse some folks. This is a completely different thing
than Bill was thinking of. Bill was using only ambient pressures and
counting the forces in helpful directions and at least partially
ignoring forces against the hull. He wasn't summing the forces
correctly. He was trying to violate Newtons third law. Gordon Alexander Ian Roxborough wrote: ************************************************************************ ************************************************************************ ************************************************************************ 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 311 Weare, NH 03281 603-529-1100 ************************************************************************ ************************************************************************ ************************************************************************Hi Bill, some research has been done on this idea. But they are two main differences between what you describe and the research I've read. First is that rather than use a horse shoe shaped stiffener, the stiffener has been made out of either a complete tube (i.e. toroid), or a longer tube coiled around the inside of the pressure vessel. The second change is that rather than exposing the inside of the tube to external pressure, they are pressurized to several times higher than the external pressure. The book "Pressure Vessels - external pressure Technology" by Carl T. F. Ross, discusses tube stiffened pressure vessels on page 286. Later on (page 321) there is an experiment using a tube stiffened dome in a pressure test tank. The tubing was pressurized to 13bar and the fail pressure of the dome was 3bar. The advantage of the tube stiffened pressure-vessels is that if you increase the internal tube pressure, you increase the crush depth. Anyway, it works, it has been done in laboratory conditions, but I do not know of a non-test tube stiffened pressure-vessel. Cheers, Ian. On Sat, 14 May 2005 08:25:13 -0400 "Akins" <lakins1@tampabay.rr.com> wrote: |