Friction Value b/w Stainless Steel Clamp and Neoprene

[knandwana]

Hi All :

I need to figure out the pull out load in an expansion joint. The joint consists of two aluminium pipe, with a 1" gap and covered with Ventglas (a heavy glass fabric double-coated with duPont's Neoprene(polychloroprene))and which is clamped at both ends with Stainless Steel Hose Clamps.

I was able to find out the pressure imposed by clamps, now I need to multiply that by the coefficient of friction to figure out axial load capacity. Where can I get an approximate value of friction coefficient b/w SS Clamp and Neoprene ?

Thanks,

Kapil,EWI

 

[MikeHalloran]

Since clamps normally bond themselves to hose, I'd have to put it at 1.0. But it doesn't matter; the clamps are otherwise unrestrained, and travel with the hose as it slides along the tube.

The problem gets more interesting as the hose slides enough to start compressing itself between the distal clamp and the hose bead, presence of which has been suggested in yet another discussion you have started.



Mike Halloran
Pembroke Pines, FL, USA

 

[DAVIDSTECKER]

Here's a suggestion.
Take regular rubber hose (air line type?) make a 360 deg loop. This will remove any sliding forces in the system.
You can get the hose fitted with pipe ends and you can just thread the whole thing together.
Another method would to work in a "U" into the line that would allow the pipe to expand and contact. If you look at the plumbing in places like a chemical plant, refinery or the Alaskan pipe line you will see this done.

Use the "KISS" method whenever possible.

 

[FACS]

Shouldn't you use the force and not the pressure for the calculation?

You can always use the inclined plane method and measure the coefficient yourself.



Charlie

http://www.facsco.com