Hose Clamp + Friction Force

[knandwana]

Hi All :

How do we find the axial load a pipe a take before it slips from the Hose Clamps at the expansion joint ?

I have two aluminium pipes wrapped around by Ventglas Sheet( Forming an expansion Joint). The Ventglas sheet is clamped to the aluminium pipe using 4 hose clamps, two on each side. The specification of the clamp is as follows :

Torque : 35 in-lbs.
Band Width : 9/16"
Band Thickness : 0.022"
SAE No. 188.

Now, I need to figue out the maximum axial load the pipe can take before the clamp slips out from the pipe. What approach is to be taken to the same.

Thanks
Kapil ,EWI

 

[btrueblood]

Go measure it. Pull on one pipe while holding the other one anchored, with a load measuring device somewhere in the string. Preferrably one with a peak hold needle.

Yeah, you could probably make a stab at calculating it...but there are a lot of variables, the biggest being the friction factor between your rubber and the aluminum pipe. You'd have to test to measure this, so why not just do one test and group all the variables into one nice, neat data point.

 

[BobM3]

This thread touches on this a bit:

thread404-251003

 

[dvd]

Weld a formed ring of round aluminum bar (~1/8" dia.) to the outside of the aluminum pipe near the end and put the clamp over the pipe and ventglas up from the ring. The ring will greatly aid in preventing the joint from slipping.