Video: active aero (grille block) via shape memory alloy
 

Really neat stuff here, directly applicable to what many of us are doing.

A GM researcher shows off shape memory alloys to Autoline Detroit TV host along with three potential automotive applications - 2 of which are active aerodynamics.

The alloys can be stretched, and return to their "memory" shape with the application of heat (or electrical current). So you can create opposing shape memory springs, and by alternately heating one or the other, move stuff (like grille louvers).

http://www.youtube.com/watch?v=VU-dChOfkAg

and it's "low cost" he said so. Too bad getting the fleet MPG standard up is going to be so expensive :rolleyes:

Sometimes I honestly wonder what they teach in business schools. I mean, surely they must all learn the doublespeak somewhere.

Hello -

This makes me wonder if "muscle wire" could be used by one of us to achieve the same result.

Shape memory alloy
http://en.wikipedia.org/wiki/Shape_memory_alloy

Muscle Wire & SMAs
http://www.robotstore.com/store/default.asp?catid=1533

Muscle Wire Kits
http://www.elexp.com/kit_2mt3.htm


Ooooooooooo, who needs Detroit, I just found the springs! :

NiTi Springs - Tension - $41.95
http://www.robotstore.com/store/prod...=85&catid=1570
Man, this is giving me Spring Fever!!!!!!!!!!

Spring Fever
http://www.youtube.com/watch?v=ngBNklagsHQ
Attachment 72

CarloSW2

Nice find!

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Did you notice the smart materials demo on the active spoiler didn't quite go as planned for the GM guy?

At around 2:50 in the vid, he deploys the spoiler, and then immediately tries to un-deploy it, saying... "Fast deploy. And... fast un-deploy!" ... as he presses the un-deploy button. But nothing happens. Yet, without missing a beat he adds, "... when we're ready for that." :)

So he delivers a few more sentences and then jabs twice more at the button, and it finally un-deploys.

I'm guessing: he just finished explaining how the alloy's "memorized" shape is activated within a predictable temperature range. So the deployment current heated up a shaped alloy, extending the spoiler, but the retracting alloy couldn't pull back down again until the first alloy cooled enough that it could be stretched again.

Neato. Tells us the alloys are more like "slow" electric motors than regular motors. (Which is still OK for things like active aero.)

active
 

I couldn't get the audio portion but enjoyed the look.Thanks Darin!
I like the potential of it.If it can get by the product liability folks we might see some if cost,cycle-life and other criteria net out in black ink.

I wonder if servos would be more predictable/dependable for such uses?

im gonna go with yes the tried and true solonoid or servo would probably out last a peice of metal flexing and stretching,, but i could be wrong.

The Rolls Royce grille is still an imitation of their original scheme. A regular bellows thermostat was hooked up to venetian-blind type slats protecting the radiator, instead of to a water valve in the water circuit. Of course, the Appearance of Rocket Science sells.