Discussion in 'Racquets' started by lgbalfa, Mar 15, 2012.
is kevlar still used in current racquets?
Yeah I want to know too, especially on the modern age Wilson Tour 90's?
What would be the advantage of having any kevlar in a tennis racket?
Bullet resistant vests, yes.
Do we shoot bullets at our tennis rackets?
Kevlar resists breakage by bending. It has low compression strength, so it doesn't contribute to stiffness in any way. Bouceback, or resilence, is depending on the bonding layer, which usually just delaminates.
So we get a racket that doesn't puncture. Is that an advantage?
Kevlar actually increases softness in a racket. My old PSC6.1's have Kevlar in them and they are like butter.
As for modern rackets having them, to my knowledge, no, not from what I've seen recently. The biggest thing about Kevlar is that it breaks down quite easily, (Bullet proof vests have to be replaced every 2-3 years I believe.) Thus in frames, they "flex out" when the Kevlar loses it's molecular integrity. I haven't heard of any modern frames flexing out.
Love kevlar-syn gut hybrid.
Kneissl includes kevlar tendons in the make-up of their racquets.
Volkl C-10. Still kevlar.
I am entirely perplexed as to what you are trying to say here. I will assume that you are not a materials or engineering type, yes?
Stiffness in composite structures rarely has to do with compressive strength, because that is most often their greatest vulnerability. Composites are typically best in tension.
As for the statement about resilence being dependent on the "bonding layer, which usually just delaminates" - that doesn't make any sense. If you are talking about the resin, that is not layer and it typically does not delaminate in all but the most extreme situations (and that is typically from abuse or from a void in the layup when the racket was formed).
Kevlar can be of benefit in a layup depending on how it is used. Kevlar has a higher specific tensile strength than carbon; it also has a lower Young's modulus, and a higher % elongation at failure. These are things that can be taken advantage of by an astute composites engineer in order tune the feel, flex, and weight of the racket.
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