Friction coefficient rubber vs paint

[metman]

The rubber material is vulcanized onto mild steel plate which is welded to a subframe as part of a 45k water tank resting on the chassis of a Caterpillar 793 Off-Highway truck. This subframe carries part of the load and fixed connections support the other portion of the load.

Durometer and scale of the rubber is 70 Shore A.

The truck chassis is painted.

We need to quantify our free body diagram for stress analysis.

Anybody know where to find verifiable coeffient of friction between rubber and painted steel?

Design for RELIABILITY, manufacturability, and maintainability

 

[MintJulep]

Your best bet might be looking at conveyor belt material manufacturers information.

But as always, if you need to know for your specific materials and application it's best to test.

 

[TomDOT]

I have to disagree with MintJulep: Coefficient of friction for different paints varies dramatically.

Luckily for you, the most common friction test for paint uses a rubber-faced sled, though if I recall correctly, it is Shore D 55-60 - a bit harder than yours.

I suggest contacting the paint manufacturer's technical rep, or their laboratory directly.

Of course, the best answer: Hire a lab to actually test your materials!

 

[metman]

Thanks MintJulep
That helps a little but yes I can test. Been there done that. Solved a really trickty problem with a simple slope test.

COEFFICIENTS OF FRICTION (µ)
Condition Steel pulley PU lagging Rubber lagging Ceramic lagging
dry 0.35 - 0.4 0.35 - 0.4 0.4 - 0.45 0.4 - 0.45
wet (water) 0.1 0.35 0.35 0.35 - 0.4
wet (soiled) 0.05 - 0.1 0.2 0.25 - 0.3 0.35

Found at the following website:

http://www.conveyorbeltguide.com/Engineering.html

Design for RELIABILITY, manufacturability, and maintainability

 

[TomDOT]

Forgot to add: Or test it yourself!

 

[dgallup]

According to my motorcycle the coefficient of friction of the double yellow lines is significantly lower than the rest of the road.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[metman]

yes dgallup be carefull on those double yellow lines.

Test completed and I do not know how we could get a more valid test (one valid test is worth a thousnd expert opinions).

A piece of the actual steel backed rubber "skirtboard" was used for the test sample and a 1/8" steel sheet painted with Caterpillar Yellow for the contact surface. This goes onto a Cat Truck.

Angle of repose measures 36.6 degrees

∴ f = tan 36.6⁰ = 0.743

Thanks for all of you input.

Design for RELIABILITY, manufacturability, and maintainability

 

[TomDOT]

dgallup - your contact surface on those yellow lines typically isn't paint. It's a layer of glass spheres ("beads") which are partially embedded in the paint to provide retroreflectivity.

 

[dgallup]

Well, those little glass beads are certainly exciting when applying 130 rear wheel horsepower through a contact patch approximately 4" x 2".

We now return you to our regularly scheduled program.


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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.