doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Question For Chuck or Rocketman (Hoop Stress)

The Alabama is of an earlier class with 16" 45 caliber guns (the caliber tells how many times of the bore diameter is the barrel length).When in the Norfolk Navel Shipyard,where I taught physics to some of their employees, I was able to crawl about many ships.I have been in the gun room of turret # 1, right gun (there is no port-starboard as the gun turns).I am 6-1 and my hard hat was against the armor over-head.Two types of projectiles AP 2700 lbs and 6 ft, High- capacity 1900 lbs 64". Range,41,000 yds. The gun only recoils 48". Each one can fire every 30 seconds and there are 9 of them.

Do not forget that hoop stress is not the only component, there is also axial stress, and that too is greater with a larger bore at the same pressure.

Guys, I haven't been able to get to this thread with some other biz going. But, for the axial concern, my recollection is axial stress is half of the hoop stress in a cylinder.

The formulae for a thinwalled tube is much simpler than for a thickwalled tube like a chamber. I'm not a stress engineer, but speculate that this problem (thickwalled tube) is fairly complex calculation and that most likely is done with FEM (finite element modeling by computer) today. Next week I may have a chance to run into some stress engineers and ask some basic questions. Hopefully, we have a more qualified structural engineer here that can help in the meantime.

Axial T = minimum oburator radius(squared) times bore pressure all divided by the quanity of (outer radius squared minus inner radius squared). Page 79.

William,
She is South Dakota Class, if I remember, and the Iowa Class included Missouri, New Jersey and...Wisconsin, maybe?

41,000 yds.= 23 miles! You can run, but you can't hide.

In another area, axial and hoop stress/strain, are very carefully considered in soda/beer cans. In the can,of which several 100 million are made in the USA every day, one tries to use the least possible material (for economics) in the construction of the can.The can is under quite a bit of pressure (shake one) and can burst.Try the formulae on that.

Those aluminum cans are a marvel of modern manufacturing. They've controlled the wallthickness so well that they can make them just thick enough to contain the worstcase pressure. You can't even pick up an openned can more than half full without buckling the outside walls.

Another new aluminum bev container is the Bud aluminum bottle. They are available in some stores in the regular and Bud Light brands. I have one that is cut in half lengthwise to see the interior, which hangs on my wall at work.

But, if an aluminum can or bottle bursts, the worst you have is a mess. If a barrel bursts, it may be a bit messier even.

Soda cans may be somewhat messier,but other cylinders may be more so.Think about repeating high pressure devices: engines (gas or diesel),brake lines,steam lines in power plants,etc.Firearm injuries pale in comparison.As far as early steel strength goes, ever heard of the Brooklyn bridge?

I imagine the steel on the Brooklyn Bridge is fairly ordinary stuff, just lots of it. Those old boilers for steam heating or power devices had a lot of failures in the early days until they figured out sufficient margins of safety above the minimum requirements when new and in-service periodic inspections came into place.

I imagine the rate of failures on aluminum cans (prior to consumer handling) is really low.