How Slippery is the Bridge
 

I am trying to figure out how slippery is the bridge for the 2012 FRC game. I think the specs are saying that the field bridge material will be HDPE. I found the coefficient for that to be .28. That seems quite slick.

The YouTube video show a battery not sliding?

Am I on the right track?

Anyone know for sure?

Thanks ahead!

Re: How Slippery is the Bridge
 

HDPE is a slick material. You are correct. You have the COF number, now compare that number with some other material you are familiar with if you don't have access to a piece of HDPE & you'll get an idea of just how slick.

Re: How Slippery is the Bridge
 

The bridge surface is polycarbonate. HDPE is the material for the bridge "deck" which is below the polycarb surface.

Re: How Slippery is the Bridge
 

That is correct. The surface is polycarbonate.

Re: How Slippery is the Bridge
 

Would that be comparable to the Lunacy surface?

Re: How Slippery is the Bridge
 

Sooooo, how slick is polycarbonate?

Re: How Slippery is the Bridge
 

According to Wikipedia, the CoF of polycarb is 0.31

To compare with wood, according to this,

Re: How Slippery is the Bridge
 

How much does the coefficient of friction change with wheel composition?

Re: How Slippery is the Bridge
 

There is no such thing as a coefficient of friction for one material (e.g. polycarbonate). A coefficient of friction is always between two materials (e.g. polycarbonate and rubber or polycarbonate and wood). You will find many examples of CoF between materials because they vary greatly depending upon the composition of the two materials. The CoF values are determined emperically. Your best bet is to purchase a sheet of polycarbonate and play with it.

Re: How Slippery is the Bridge
 

So in other words, Posting the coefficient of friction gives no help at all because it various between materials. We need to experiment. Good thing our mentor has about 20 sheets of 1/8 in polycarbonate lying around. mwahahah.

Re: How Slippery is the Bridge
 

Make sure you remove the masking material, if there is any. If you leave that on, your results will be inaccurate.

Re: How Slippery is the Bridge
 

What? And get scratches on it? Won't that change the CoF too? You mean Cof will be different in Elims than it was in Quals? week2 differs from week1? Week 6 balancers will have a cake walk on the scratch-covered bridges. Or do you think we'll get fresh polycarb each tournament? :p

All hail the goddess of uncertainty! I mean, I would if I knew in which direction to genuflect. ;)

Re: How Slippery is the Bridge
 

if your wondering you are pretty much driving on a white board for the ramps which is really slick depending on the wheels you are using for this year, if you use the wheels from the KOP you have no problem on the bridge but if you use mechanum wheels you will be sliding all over the place on the ramp during the game

Re: How Slippery is the Bridge
 

I dont think so. The mechanum wheels are a soft-ish rubber I think they will grip quite well, I also saw a youtube video of some one going up a bridge with mechanums.

Re: How Slippery is the Bridge
 

We had some hdpe laying around the shop, took one of the wheelchair wheels to it, the wheel stuck surprisingly well.