Ski Mapping

[Than_Bogan]

I didn't mean that, but I should have. I was just thinking backwards about how width affects torsional stiffness. Anyhow, still more a coincidence of width than a plan?

[Adam Caldwell]

@Than_Bogan - makes you wonder!

[BraceMaker]

@adamhcaldwell understood - I don't necessarily mean the value or even the units. But the idea that a blank of uniform torsional stiffness would be a flat line tells me all I need to know about the unit.

[BraceMaker]

@Than_Bogan wouldn't thickness be more of a torsion limiter than width? a 4" wide strip of cardboard has no torsional stiffness, a 4" wide strip bent into a 1" square tube has quite a lot more..

[CsSkis]

@bracemaker - Apples versus Oranges - You just introduced 4 shear planes when you created a 1" square tube (assuming the end condition retains the 1" square under load). The assumption with the 4" sheet of cardboard is that it is 2-dimensional with only 1 "shear" plane. So, thickness, by itself, doesn't increase the torsional stiffness. For example, if you could separate 2 sheets of 2" wide cardboard with an air gap (of any thickness), they would have the equivalent overall torsional stiffness as the 4" wide strip.

 

But, after saying all of that, I agree with the point you were trying to make! The best case, from a torsional stiffness standpoint, it to use your 4" strip of cardboard to make it into a tube. That's why airplanes went to monocoque structures.

 

Ok, so when do we start riding tubular skis?