use of kers for stiffening

[aral]

a couple of years ago, head skis produced a racing ski fitted with kers. sounds odd, but it is now being used in normal skis. I don't fully understand how it works, but it appears that the flexing of a skican cause a microchip to store energy, and when the flexing stops at the end of a turn, the energy is released back into fibres, stiffening the tail of the skis, resulting in increased accelloration out of the turn.
it is a rather interesting process, and I wonder if it could be, or is already, used in f1 to produce either stiffness or flexibility on demand. could be the reason for some of the flexing issues over the last year or two.
google "kers on skis" to see a brief description.
anybody have any thoughts on this technology?

[xxChrisxx]

Word salad.



But the idea of piezoelectrics being used to alter stiffness is interesting.

[Holm86]

Yes I saw a program that mentioned this several years ago. It was a piezoelectric surface to stop the skies from vibrating. I don't think they can change the stiffness but they could absorb vibrations.

It works by taking vibrations and turning them into energy instead. Heat for an example. Its not like you have to send electricity to the piezo plates.

[youtube]http://www.youtube.com/watch?v=wLGjFoD1LKs[/youtube]

[Pup]

I believe dampers with piezo valves are already in use. Aren't Koni FSD dampers piezo activated?

I think there is also occasional talk here about dampers that use piezo-activated variable viscosity fluid.

That's not exactly storing/releasing energy, though - I'd think doing so would be considered an active suspension.

Doing so on the sly, via chassis flexibility, is an interesting thought.

[Lycoming]

In an F1 car, most things you simply want to be as stiff as possible, you only stop at some point because of weight.

Some things, you want a very, very specific stiffness; and you can achieve that without any fancy piezoelectronics.

And then there are some things where you want to vary the stiffness on the fly based on how the situation is changing. Pretty much all of these are banned. For example, an MR damper, where you can vary the viscosity of the fluid by sending different amounts of electrical current to it. This is of course not legal as it is active suspension

[Holm86]

I think this is what you were looking for??

A board, such as a ski or snowboard, that includes a piezoelectric damper. The piezoelectric damper is located on the body of the board such that, as the board vibrates or deforms, the piezoelectric material is also deformed. As the piezoelectric material deforms, it produces an electrical signal that is provided to a control circuit. The control circuit receives the electrical signal and either provides a resistance to the electrical signal or provides a control signal to the piezoelectric material. The resulting resistance or control signal causes the piezoelectric material to resist the deformation of the board, thus acting as a damper. The piezoelectric damper may be located between the bindings on the board, or may be located in front of the forward binding, behind the aft binding, or in more than one location. In the preferred embodiment, the piezoelectric damper is formed of one or more layers of piezoelectric material on which an electrical grid has been mounted. The piezoelectric material and electrical grid are encapsulated within an organic matrix, such as an epoxy or plastic resin.

http://www.google.com/patents/US5775715

Its not making the material stiffer. Its dampening its vibrations. I think a such material could be usefull somewhere on an F1 car. The endplates for instance. I've seen onboard shots where the endplates are vibrating because they are so thin. And when they are moving in a frequency like that it can't be good for aerodynamics?

[aral]

thanks. but this does not seem to be quite what HEAD are using. have a look at their site. it is not for absorbing pure vibration, but accumulates and stores energy, to be release as the bending of the ski in a turn, stops. it appears to be a controllable (programmable?) point of release and is clearly stated as causing STIFFENING

[Holm86]

[youtube]http://www.youtube.com/watch?v=UgblylU2VpY[/youtube]
[youtube]http://www.youtube.com/watch?v=CYiLj_6K6jw[/youtube]
[youtube]http://www.youtube.com/watch?v=onf450LGq3c[/youtube]

[Holm86]

But I would take HEAD's explanations with a grain of salt. Its also HEAD who produces a tennis racquet which features "graphene". And many believes that this is just a marketing feature and that these racquets has no graphene in them what so ever.

[autogyro]

But I would take HEAD's explanations with a grain of salt. Its also HEAD who produces a tennis racquet which features "graphene". And many believes that this is just a marketing feature and that these racquets has no graphene in them what so ever.

I would definitely want to know the energy available to alter the rigidity of the ski.
I cant see anywhere near enough generated from piezoelectric technology.
God enough for Epson print heads hardly enough for this application.

[Blanchimont]

So, the energy source is the flexing of the ski and the KERS is a system to reduce the flexing, therefore the source of energy is eliminated?

[autogyro]

So, the energy source is the flexing of the ski and the KERS is a system to reduce the flexing, therefore the source of energy is eliminated?

They say the energy is stored in a 'chip'.
Must be some chip to store enough energy to make a ski rigid.
Once the ski goes rigid of course, no more energy generated.
If it wasnt for the very low energy available it would act like a bouncy kangaroo.

[Holm86]

It is definitely possible to do. A piezo crystal works both ways. If you compress it it produces energy. If you ad a current to it it will contract. Its piezo crystals who creates the spark in those click lighters and gas grill ignitors.

They way this works as I understand it is that during the flexing of the ski during a corner energy is created and stored. Then it is released on the exit. Sort of a bound and rebound effect where you can control when the rebound occurs.

[autogyro]

It is definitely possible to do. A piezo crystal works both ways. If you compress it it produces energy. If you ad a current to it it will contract. Its piezo crystals who creates the spark in those click lighters and gas grill ignitors.

They way this works as I understand it is that during the flexing of the ski during a corner energy is created and stored. Then it is released on the exit. Sort of a bound and rebound effect where you can control when the rebound occurs.

So how do you control it then?
In most circumstances the ski will be seeing about one G, so it wont know if it is on a corner or not.
It is easy to measure the ground surface from flex frequency but when do you re-apply the energy and when the ski goes rigid, how do you gain more energy?
I can make a cats whisker radio work with a piezo crystal and Epson printers do indeed work the other way by applying current to piezo crystals to fire an ink jet, you would need a huge crystal to make this ski idea work though.
Perhaps if you made the whole ski out of crystal that might work and you could name it Cinderella on ice.

[Holm86]

It is definitely possible to do. A piezo crystal works both ways. If you compress it it produces energy. If you ad a current to it it will contract. Its piezo crystals who creates the spark in those click lighters and gas grill ignitors.

They way this works as I understand it is that during the flexing of the ski during a corner energy is created and stored. Then it is released on the exit. Sort of a bound and rebound effect where you can control when the rebound occurs.

So how do you control it then?
In most circumstances the ski will be seeing about one G, so it wont know if it is on a corner or not.
It is easy to measure the ground surface from flex frequency but when do you re-apply the energy and when the ski goes rigid, how do you gain more energy?
I can make a cats whisker radio work with a piezo crystal and Epson printers do indeed work the other way by applying current to piezo crystals to fire an ink jet, you would need a huge crystal to make this ski idea work though.
Perhaps if you made the whole ski out of crystal that might work and you could name it Cinderella on ice.

I don't know. I didn't invent these skies Though I know that a piezo film does work to stop vibration in a ski. I've seen that myself. And that you can read about in the patent link I posted earlier.