Moment of intertia for corrugated pipes

AI Thread Summary
The discussion focuses on calculating the Moment of Inertia (MOI) for corrugated hollow pipes, specifically a solid wall pipe with a smaller diameter hollow plastic pipe spirally welded onto it. The user needs the MOI to determine pipe stiffness and deflection under load. Suggestions include calculating a unit moment of inertia and approximating it using the inner tube while applying parallel axis theory for accuracy. Additionally, it is noted that commercially produced pipes often have published tables with relevant data. The conversation emphasizes the importance of these calculations for structural analysis.
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Hi,

I am struggling to find forumula for Moment of Inertia for corrugated hollow pipes somewhat as shown in the picture.

Main Pipe is made of Solid wall construction over which smaller diameter hollow plastic pipe is spairally welded.

Any approximate calculations will also help. Thanks, Aktan

Corrugated-Pipe.jpg
 
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That's a bellows that's designed to be flexible, why do you want a MOI for it?
 


Mech_Engineer said:
That's a bellows that's designed to be flexible, why do you want a MOI for it?

Yes , we have flexible corrugated plastic pipes somewhat similar to given in picture. I require MOI to calculate pipe stiffness, that will be used further to calculate pipe deflection under a given load.

Thanks
 
Normally you'd just calculate the a unit moment of inertia, in^4/in and depending on how perfect you want the value, you either approximate it as the inner tube if it is a simple pipe with the corrugations applied to the outside as stiffeners, and use parallel axis theory to combine. Most commerically produced pipe have tables published with all this data.

http://www.dot.ca.gov/hq/esc/techpu...idge-design-specifications/page/section12.pdf
 
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