
maximum pressure calculation  
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Posted by: Lex ^{®} 01/03/2007, 20:45:39 Author Profile eMail author Edit 
I'm trying to calculate the maximum pressure that a piece of pipe can hold. The pipe has a round inner bore, but the outside is square. Since the bore is centered in the square the thinnest part of the pipe is in the center of the flat sides of the pipe. I could use a hoop stress calculation based on the thinnest part of the wall, but I'm trying to be more accurate and take into account that the thinnest part of the wall occurs only at one small part of the pipe. Does anyone have a model for this type of calculation? Material can vary but is generally 316. 
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Re: maximum pressure calculation  Lex  Post Reply  Top of thread  Forum 
Posted by: swearingen ^{®} 01/04/2007, 08:11:35 Author Profile eMail author Edit 
The most basic way to look at your situation is to take a free body diagram of half of the pipe and look at the forces required to resist the internal pressure at the thinnest part. You'll find that it's the same as a hoop stress analysis. Think about it, the pipe's wall is only as strong as it's weakest link  it's the same as if that thin wall was constant around the pipe. Understand that this is not EXACTLY true, there is a little difference, but it will be very close to the standard hoop stress number. I'm curious  when I get some free time, I'll set up an FEA model and see just how close they are... 
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Re: Re: maximum pressure calculation  swearingen  Post Reply  Top of thread  Forum 
Posted by: Lex ^{®} 01/06/2007, 01:19:39 Author Profile eMail author Edit 
What's an FEA model? I don't know if the sizes involved would be a major factor but in many cases the inner diameter is less than 1/2" and the thinnest part of the wall is generally about 0.020".

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Re: Re: Re: maximum pressure calculation  Lex  Post Reply  Top of thread  Forum 
Posted by: Lex ^{®} 01/06/2007, 02:02:52 Author Profile eMail author Edit 
FEA, finite element analysis, I should have known that one 
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