What is pop?

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endre
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Post by endre » Fri Mar 31, 2006 12:31 am

It would be very surprising if that was possible, Alex. Most materials have linear flex characteistics. (exeptions are f.ex metals after bending etc.)

Alex
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Post by Alex » Mon Apr 03, 2006 12:56 am

That's rigth endre - just rubber and some plastics e.g. provide progressive characteristics. The thing i'm talking about is the way you combine different materials in the layup. Depending on the position in the laminate and the way the force is brought into the material layers take different amount of load depending on the deformation.

Think of a layup some ski/snowboard builders use:

first layer above the core with carbon rovings/UD and than some glass above.

When flexing this the glass should takes most load first (the outer fiber). At increasing angle the carbon takes more and more load - with the flexible matrix and fibers have to straighten first it takes some deformation. This should lead to a progressive characteristic.


Hopefully you can follow my thoughts and once again: this is just an idea to explain the behavior i experience when flexing ski's with carbon reinforcement.

Svimen
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Post by Svimen » Thu Apr 06, 2006 3:28 am

Pop is, in my opinion, how much extra vertical force you can generate by ollieing (leaning quickly on your back tips, or front tips if you have a lot of guts) before takeoff.

How much pop a ski has depends on the skiers weight and the stiffness of the ski. (Thinking along the lines of an adjustable diving board, depending on your weight and skill level, you can adjust the stiffness of the board to suit your taste.)

If the ski is very soft, you will bend it a lot, but very little energy will be stored in the ski, and you will not get a lot of rebound.

If the ski is very stiff, you will not be able to bend it at all, and you will not get any rebound at all.

Somewhere in between these two extremes lie the ski that gives you maximum pop. (I´ll leave it to you physicists out there to calculate this.)

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