Only metal foam crumple zones can provide the biggest mpg advantage!

[drmiller100]

Originally Posted by jakobnev

You know the energy needed to accelerate isn't lost, right?

I'll bite. Ignoring the Prius and other hybrids, how are you "saving" that energy? Heating the brakes at the next stop sign?

[redpoint5]

Originally Posted by drmiller100

I'll bite. Ignoring the Prius and other hybrids, how are you "saving" that energy? Heating the brakes at the next stop sign?

An object in motion stays in motion.

Coasting is a great way to use the kinetic energy stored by the weight.

Of course, an accelerated objects energy is always lost on earth due to friction- be it aero, rolling, or brakes.

[brucepick]

Originally Posted by drmiller100

Cars have been doing this for 20 years plus. Plastic and foam have been front and back of many cars, including hondas, since the early 90's.

The weight of the crumple zones is not very much.

I believe that good drmiller has misunderstood.
We are referring to aluminum foam, and also to titanium foam. Not referring to aluminum PLUS common plastic foam, which indeed has been in use for many years. Foamed metal apparently has significant strength - though it does crumple - and light weight. Apparently deal for - you guessed it - crumple zones.

I googled "aluminum foam crumple zone reasearch"
and "titanium foam crumple zone reasearch".

I found these links, among others:

http://cvxmotion2.wikispaces.com/Jac...ouglasResearch
http://www.materia.nl/575.0.html?&user_material[material_uid]=439&cHash=10e5e231b2
Center for the Science & Engineering of Materials @ Caltech
AUTOMOTIVE INDUSTRY DEVELOPMENT CENTRE :: NEW METAL THAT'S FULL OF HOLES
http://www.google.com/url?sa=t&rct=j...RPEpmAiazfr2rw

[brucepick]

I haven't been a big fan of reducing the weight of my Civic. Maybe I should, but I still want to have a passenger seat, real safety glass windows, etc. etc. I'm too thrifty (aka CHEAP) to get carbon fiber hood and other parts. And I like to carry my tools in the car. Otherwise my son has been known to borrow them...

That said, manufacturers are in a good position to reduce the weight of vehicles in the design stage, and they've been doing this for many years. They've also been complying with gradually increasing safety standards, so IMHO most cars have gradually gotten heavier. But if they can reduce weight and get improved crumple zones, I'm all for it.

[NeilBlanchard]

Moving weight = kinetic energy. Once you have "invested" energy accelerating a vehicle, you can then use that kinetic energy to coast. You lose energy to aero drag and rolling drag -- both of these are a total loss.

This is why aero drag is more important most of the time than weight -- aero drag is a majority of the drag most of the time, and it is a total loss. Kinetic energy can partially used, and if your drivetrain is very efficient and if your drag is low, then weight matters less than if the drivetrain is not efficient and /or the chassis is high drag.

[kach22i]

Here is an idea, combine the need for energy absorbing foam with that of storage battery for a hybrid or all electric car.

Carbon foam as I recall it, was developed under DARPA as a heat resistant foam for aircraft using composite construction (my facts here may be fuzzy). It has unusual electrical properties, a great conductor and something about static charges being held (and or attracted) which didn't make it the best thing to fly in during a thunderstorm.

Carbon Foam: The Key Ingredient of a Better Battery?
Carbon Foam: The Key Ingredient of a Better Battery? | Michigan Tech News

Their cathode relies on nickel oxyhydroxide, the same material used in rechargeable nickel-cadmium or nickel-metal hydride batteries. “In most batteries that contain nickel oxyhydroxide, metallic nickel serves as a mechanical support and a current collector,” said chemistry professor Bahne Cornilsen, who had been studying nickel electrodes for a number of years, initially with NASA support. A few years ago, the Michigan Tech team had a chance to experiment with something differ

EDIT: If anyone knows what happened to the real/original Carbonology company which made T-Foam I'd like to know what happened to them. Looks like another company took their name now.