Reaction Loads on Bent Hose 1

[Twoballcane]

Hello All,

OK I got one that I'm stumped on that came accross my desk. I have a hose that is 4in in diameter, 50in in lenght, and has a 3.5ft bend radius. Once 250psi is applied, what is the reaction forces at each end of the hose to keep it in a 3.5ft bend radius? I'm calculating the load to be F=PA, so A=(4)(50)=200in^2 (area down center of hose), thus F=250(200)=50,000lbF. The reaction loads would be 25,000lbF on each side of the hose. Wow that is huge! I'm doing somthing wrong.

Thank you in advance for your help!

Tobalcane
"If you avoid failure, you also avoid success."

 

[drawoh]

Twoballcane,

Is it valid to assume that your hose is a stiff beam? There is a separate set of equations to describe the behaviour hanging ropes and chains, which may be more accurate at describing your hose. I am not even going to try to describe this.

Will the hose deform elastically at maximum stress, or will it buckle?

JHG

 

[Twoballcane]

nope this was a fluids problem.

Tobalcane
"If you avoid failure, you also avoid success."

 

[chicopee]

To restrain the hose under fluid flow is fairly easy to calcule using the momentum proposed above so get a static-dynamic text book.
To restrain the hose under static condition think of a bourdon tube springing back under changes of internal pressure. Such the internet for analysis of bent tubes under internal pressure, I am sure you'll come across some thesis and read the paragraphs dealing with longitudinal and radial strains that will allow you to determine the restraining forces.

 

[chicopee]

"Tubular Steel Structures-theory and Design" by Troitsky and published under "The James F. Lincon Arc Welding Foundation, 2nd edition 1990 Section 9.3.2 Stresses in Circular Bends has three formulae 9.4,9.5,9.6 to determine tensile stresses in the ExtraDos, Middle section and IntraDos of thin wall tubing. In all likelyhood, if you average these values you will approximate the straight pipe formula. Using the straight pipe formula, you can calculate the tensile force to restrain the pipe ends while under internal pressure. Discount stresses from end moments as you are dealing with a flexible hose. If you are interested, I'll JPEG the page with formulae and drawing.

 

[Twoballcane]

Thanks chicopee!! But, I'm all set ...

Tobalcane
"If you avoid failure, you also avoid success."