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Forums10
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Apr 29th, 2024
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Joined: Nov 2008
Posts: 532 Likes: 26
Sidelock
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Sidelock
Joined: Nov 2008
Posts: 532 Likes: 26 |
Not sure it makes any difference to the discussion of what loads to shoot but, hoop stresses are in fact highest on the inside face. You cant figure it out from the Pr/t equation (a simplification) You need a different method.
Hoop stress = ri^2 x P/(ro^2-ri^2)x(1 +(Ro^2/r^2))
ri = inside radius, ro = outside radius, r=spot in question (r=ri if you want the max stress)
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Joined: Jan 2002
Posts: 11,385 Likes: 106
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 11,385 Likes: 106 |
With March Madness almost upon us, I thought hoop stress had something to do with a 7' center hanging on the rim!
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Joined: Feb 2012
Posts: 19
Boxlock
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OP
Boxlock
Joined: Feb 2012
Posts: 19 |
At the end of the day, I'm confident that Sherman Bell calibrated his strain gauges properly; he seems to be a careful fellow. To simplify,
Hoop stress = Chamber pressure x (other things that RyanF mentioned)
or
Chamber Pressure = Hoop Stress/(other things that RyanF mentioned)
Last edited by KirkD; 03/06/12 09:31 PM.
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Joined: Feb 2004
Posts: 13,880 Likes: 16
Sidelock
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Sidelock
Joined: Feb 2004
Posts: 13,880 Likes: 16 |
Not sure it makes any difference to the discussion of what loads to shoot but, hoop stresses are in fact highest on the inside face. You cant figure it out from the Pr/t equation (a simplification) You need a different method.
Hoop stress = ri^2 x P/(ro^2-ri^2)x(1 +(Ro^2/r^2))
ri = inside radius, ro = outside radius, r=spot in question (r=ri if you want the max stress)
I've always believed it was higher on the O.D.in part due to the bending moment of the wall. I also understood that a thick wall cylinder had different force ratios going on than thin wall cylinders. Is that what you refer to?
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Joined: May 2004
Posts: 2,092 Likes: 13
Sidelock
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Sidelock
Joined: May 2004
Posts: 2,092 Likes: 13 |
Also from Wikipedia: Fracture is governed by the hoop stress in the absence of other external loads since it is the largest principal stress. Note that since the hoop stress is largest when r is smallest (nope, when r is largest), cracks in pipes should theoretically start from inside the pipe (nope, the outside should fail first).
Rocketman: This was a direct quote from Wikipedia including the last sentence. It was not a conclusion I drew from it. My comment was it seemed contradictory.
So many guns, so little time!
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Joined: Dec 2001
Posts: 3,595 Likes: 10
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 3,595 Likes: 10 |
I read that you have a roll crimper, but if you are wanting to save some time, you might consider the "Hartin Crimp".
Cut hulls to 2 1/2".
Load as normal.
Insert overshot card.
Star crimp as normal.
I don't have a picture or I would post one.
Mike
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Joined: Nov 2008
Posts: 532 Likes: 26
Sidelock
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Sidelock
Joined: Nov 2008
Posts: 532 Likes: 26 |
This diagram shows the stress distribution For a thin wall cylinder the inside and outside stress is almost the same. The area just ahead of the chamber probably doesnt qualify as thin walled. Most of the barrel certainly does. 
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Joined: Jan 2002
Posts: 5,954 Likes: 12
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 5,954 Likes: 12 |
My bad, builder and thanks for the material, Ryan. What happens when you push a simplified formula too far. Also, i agree with Ryan that the chamber doesn't fit the criteria of a "thin" cylinder and must be treated with a differing formula for precision calculations.
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Joined: Oct 2006
Posts: 1,544
Sidelock
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Sidelock
Joined: Oct 2006
Posts: 1,544 |
Why not just buy some 2 1/2" shells from RST?
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Joined: Oct 2009
Posts: 6,498 Likes: 396
Sidelock
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Sidelock
Joined: Oct 2009
Posts: 6,498 Likes: 396 |
Why not just buy some 2 1/2" shells from RST?
Just curious Dig, do they sell RST in Britain? I'm always annoyed because they aren't available in Canada. At least not that I have found so far.
The world cries out for such: he is needed & needed badly- the man who can carry a message to Garcia
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