Collapse pressure of a thick walled cylinder
Collapse pressure of a thick walled cylinder
(OP)
Hi,
I am trying to find the collpase pressure of a thick walled cylinder (thick walled since thickness, t>ro/10). The yield of the material is 130000 psi. The cylinder has a inner radius of ri=1.8125in, outer radius of ro=2.25in, and a length L=48in.
Can anyone provide me a reference to calculating the collapse pressure? I am also not sure if I can use Lame's equation to find the collpase pressure?
Found one formula in the design handbook but it is not for a cylinder closed at both ends, and they have no information on how they arrived at the equation.
Thanks,
Mike
I am trying to find the collpase pressure of a thick walled cylinder (thick walled since thickness, t>ro/10). The yield of the material is 130000 psi. The cylinder has a inner radius of ri=1.8125in, outer radius of ro=2.25in, and a length L=48in.
Can anyone provide me a reference to calculating the collapse pressure? I am also not sure if I can use Lame's equation to find the collpase pressure?
Found one formula in the design handbook but it is not for a cylinder closed at both ends, and they have no information on how they arrived at the equation.
Thanks,
Mike





RE: Collapse pressure of a thick walled cylinder
The end-closure will have some impact on the collapse pressure,as will the tube filling (liquid,gas, etc.).
RE: Collapse pressure of a thick walled cylinder
RE: Collapse pressure of a thick walled cylinder
EN13445 gives a formula to calculate the buckling pressure for a cylinder of given length, but of course, with your proportions and as you correctly implied, it is much higher (about 3 times) than the pressure required to fully yield the thickness.
The latter is simply calculated as Yt/r=28 ksi. This value would be the basis for determining the allowable external pressure, not far from half of it.
But if you are trying to determine the actual collapse pressure, then things are more complex.
First observation is that, if your pipe was a solid bar, then virtually no collapse would be observed for any pressure. So your pipe will go well beyond the above value without displaying any failure, with only a small permanent reduction in diameter.
Now how far will it go? I suppose that some answers could be found in the literature, but suspect that if the pipe has no dimensional or material non uniformities, it would resist up to the buckling pressure (around 80 ksi).
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RE: Collapse pressure of a thick walled cylinder
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