Is there any method to evaluate buckling in large bore piping or ducting system?

[Milad.Hmk]

Hi stress engineers
As we know, buckling analysis is very important issue for piping and ducting systems with large diameter.
Is there any method or criteria to evaluate the buckling in these systems ?

 

[JStephen]

Buckling of thin cylinders due to external pressure, axial load, overall bending moment, etc., is fairly well addressed in various places. Some of the critical buckling loads will be tabulated in Roark's Formulas For Stress and Strain. I believe there are some AWWA and perhaps AISI manuals on steel piping and penstocks that address buckling to some extent. Codified formulas may be found in the tank and pressure vessel codes, to some extent in the structural steel codes. if you can be more specific about the situation, you may find more specific help on the topic.

 

[Milad.Hmk]

@JStephen
Imagine a complicated piping or ducting system (with straight runs and elbows or miters)between anchor points, not only a thin cylinder. How can we perform a buckling analysis with a FE software?

 

[MJCronin]

FE is not the best analysis tool for all situations....Sometime proven manual methods are best.

This is a superb AISC book that has been in use for decades... It addresses stability and buckling analysis for round and rectangular ductwork

https://ascelibrary.org/doi/book/10.1061/9780784401125

No.... I will not give it to you for free ...

MJCronin
Sr. Process Engineer

 

[racookpe1978]

In general, and from the way you phrase your question, I take it you are not an experienced large bore pipe stress nor HVAC engineer, you cannot compare the established pipe stress (thermal expansion and pressure) analysis processes with the very thin wall, lightweight duct (HVAC) processes.

Pipe stress calc's (manual and computerized) assume high internal pressures , medium to very thick pipe walls, high fluid weights and high fluid temperatures. HVAC assume very low pressure gasses flowing at near-room temperatures, with "cooling capacity" flowrates and velocities and extremely thin pipe and sq duct walls. Flanges behave differently, anchors behave differently, and - although both are "round hollow things carrying fluids and gasses" - both behave very, very differently.

FEA is ill-suited for either analysis.

 

[Milad.Hmk]

Thank you all for the input.