Min cylinder wall thickness for an exterior pressure
I saw the thread about calculating the minimum wall thickness of a cylinder for a given pressure inside, but what about when the exterior pressure is greater?
Does anyone have a handy calculator, chart or graph?
probably the same way. what you're really calculating against is a pressure difference, so instead of 300 psi on the inside and 14.7 psi (atmospheric pressure) on the outside, it'd be the other way around. might actually be able to make it thinner since the cylinder would be able to handle more force on the outside due to its shape, but that's a little less on the handy calculator side and a little more towards a solid mechanics textbook.
funny, we were just told about engineering tool box in a 2000 level engineering class today, by someone from the library who was teaching us how to do research (its not like anyone in the class had never heard this presentation before, except for that part).
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Team Captain: WPI Engineers Paintball"Originally posted by xsport37: so, what have we covered today kids?
Politics, Religion, Philosophy, Quantum physics, Mixed drink recepies"
think those are going to go in my bookmarks as well, although i could have used them last semester...
make sure to read the notes at the bottom of the thin-walled page, it explains pretty well what that formula is valid for, as well as what to do for external pressure.
Oh yeah. And the corners of your cylinder can easily see way more stress than the walls. These equations really only work for things like pipes which use much thicker fittings than the walls (in this case, the pipe will burst before an elbow for example).
If you machine a tube and pressurize it near the yield stress based on the hoop stress, you are very likely to crack in the corners of the tube.
pressure is pressure, doesnt matter. although the surface area will be greater so make sure you measure the outer surface area. (greater surface area=more force @ constant pressure)
if your oppererating at low (under 300 psi) pressure then you are really safe.
look at how thin an ion firing chamber is.(the back half) thin as balls.
I took an angle grinder to the outside of my ion aswell....... closed my eyes and looked away first time I pressured it up, but you have no worrys if your opperating at low pressures.
ontop of this, if you just use hosing rated at lower pressures then you have a "safety" built in. (hose will burst before the firing can explodes)
and if the pressure is too low to blow a rubber hose off, it will be too low to do anything other than crack or cause a pin hole leak in an aluminum pressure vessel.
now... if you plan on pressurizing to 800psi I would tell you not to do it if you have to go on ****ing PBNation for fact checking.
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