New Type of an aerogel airbag system for cars

[adlep]

I was thinking about designing a new aerogel based -airbag/passive protection system for cars. It is quite simple actually:

1. The impact happens. Computer sensor detects and calculates the force of an impact and its direction. It then could calculate the best method of dissipating the energy of the impact without hurting the passengers inside.

2. The aerogel canisters would start deploying the aeorgel inside of a car, so that it creates the mold around the occupants. The mold would absorb the bulk of the energy.

3. The properties of the aerogels make it a very suitable for such an application. The material compresses heavily, but it is also a very brittle. Think of it a an uber light and super strong version of the styrofoam.

4. The aerogel can absorb up to 4000 times of its own weight. Meaning that the 1kg aerogel bottle (s) could absorb an impact equal to 4 metric tons (or 10,000 lb).

5. It is also almost a perfect insulator. In case of a fire, the aerogel mold could absorb the heat until the help arrives.

6. Because the material is very brittle, it would be quite easy to dismantle it quickly.


Should I proceed with the idea?

 

[PottedMeat]

If you're knocked out, would you suffocate?

And last time I read, Aerogel was fairly difficult stuff to manufacture.

 

[CycloWizard]

Would the vehicle's occupants be able to breathe after the gel deploys? Could you really calculate the "best" method for dissipating the energy of a crash in a reasonable amount of time? Is the gel strictly elastoplastic, or viscoplastic? Could be a cool solution if you could really get it to do this, and I'll admit I know a lot more about hydrogels than aerogels, so maybe it is feasible.

 

[adlep]

Originally posted by: PottedMeat
If you're knocked out, would you suffocate?

And last time I read, Aerogel was fairly difficult stuff to manufacture.

Well, at first, everything is difficult to manufacture. The idea does not take the cost into the account. But if the proof of concept works, it may get accepted into the production. Mass production of the aerogel would push the price of this material down.

Everything new is always expensive.


In terms of suffocation, I do not think that it will happen. The system would not fill the entire space inside. But it could create a race car "safety cage" around the driver made out of the aerogel beams. The cage aeorgel "beams" would be strengthen around where the impact happens.

So I guess my system would act as a supplemental crumple zone, inside of the passenger's compartment or even.

Could you really calculate the "best" method for dissipating the energy of a crash in a reasonable amount of time?

That will not be a problem, what I am not sure however is if the aerogel will have enough time to deploy and form into a solid within the required few miliseconds.

 

[PlasmaBomb]

Originally posted by: adlep

I was thinking about designing a new aerogel based -airbag/passive protection system for cars. It is quite simple actually:

1. The impact happens. Computer sensor detects and calculates the force of an impact and its direction. It then could calculate the best method of dissipating the energy of the impact without hurting the passengers inside.

2. The aerogel canisters would start deploying the aeorgel inside of a car, so that it creates the mold around the occupants. The mold would absorb the bulk of the energy.

3. The properties of the aerogels make it a very suitable for such an application. The material compresses heavily, but it is also a very brittle. Think of it a an uber light and super strong version of the styrofoam.

4. The aerogel can absorb up to 4000 times of its own weight. Meaning that the 1kg aerogel bottle (s) could absorb an impact equal to 4 metric tons (or 10,000 lb).

5. It is also almost a perfect insulator. In case of a fire, the aerogel mold could absorb the heat until the help arrives.

6. Because the material is very brittle, it would be quite easy to dismantle it quickly.


Should I proceed with the idea?

What do I think?

Have you ever seen Demolition man?

1). Yup just program the computer with the conditions to deploy, like an airbag. The question is could you deploy it fast enough? Aerogels are produced by extracting the liquid component of a gel through supercritical drying. How are you going to get aerogels to work in a car?

2). So the aerogel deploys... what happens if the persons mouth is open? The gel has to fill the space in the car, so is rapidly expanding, it won't know to not go down someone's throat, which is not cool. Even if your mouth is closed it will still go up your nose. Still not cool. Aerogels act as strong desiccants, handling it can cause the skin to become dry and brittle. Not cool. Also it will dehydrate your mucus membranes (eyeballs and nasal cavity), which is very not cool. Silica based aerogels are a mechanical irritant to the eyes, skin, respiratory tract and digestive system. You will need to treat the aerogel to make it hydrophobic...

3). They are quite friable, and if you apply a large force you can crush them... the rapid application of a large force would probably be disruptive, and the aerogels would likely not perform optimally.

4).
a) Force isn't measured in mass.
b). 4 metric tonnes != 10,000 lb.
c). They are quite fragile.

5). It is a good insulator but I don't think you know how insulators work. They can't absorb much heat since they have very little mass. Aerogels prevent conduction and convection/radiation.

6). Quick to dismantle, like quickly during the crash unfolding?

 

[CycloWizard]

Originally posted by: adlep
That will not be a problem, what I am not sure however is if the aerogel will have enough time to deploy and form into a solid within the required few miliseconds.

So I take it you would simply read some accelerometers to figure out where the cushion is needed, rather than a full-blown "calculation" of where, when, and how much foam is needed? That would be feasible, certainly. I assumed that you had the kinetics worked out and that that was why you were thinking of this application. Like I said, I'm not terribly familiar with aerogel chemistry, but I'm sure it's possible to find one that reacts very quickly and expands rapidly. The problem would then become controlling that expansion to the desired shape and timing it with the reaction.

Perhaps an alternative method would be to develop a giant airbag system that deploys similar to a typical airbag, only filling with the aerogel rather than just a gas. This allows tight control over the shape of the cushion and would just require you to find a substance that expands and gels fast enough. Easier said than done, obviously, but it should reduce the degrees of freedom in the system enough to make it a little more feasible in the short run.

 

[silverpig]

Demolition Man called. It wants its idea back.

 

[silverpig]

Originally posted by: PlasmaBomb

4).
a) Force isn't measured in weight.
b). 4 metric tonnes != 10,000 lb.
c). They are quite fragile.

Force certainly is measured in the same units as weight.

 

[Modelworks]

I think it would be very hard to deploy any chemical compound that then dries in the short time required. Like under 2 secs.

 

[CycloWizard]

Now that I think about it, there is a group working on controlling how foams "grow" and harden with time. This group is still struggling to simulate the process, despite having one of the fastest supercomputers in the world and possibly the most sophisticated finite element software in existence. In their case, I think the timescales involved are much longer than yours, meaning that their simulation should be much simpler than yours. While you obviously wouldn't have to do this during an accident, if you really were planning on having the foam form in a known shape in a known amount of time, you would almost certainly have to simulate the process to have any chance of success. If you really want, PM me and I can give you the group leader's contact information.

 

[PlasmaBomb]

Originally posted by: silverpig

Originally posted by: PlasmaBomb

4).
a). Force isn't measured in mass.
b). 4 metric tonnes != 10,000 lb.
c). They are quite fragile.

Force certainly is measured in the same units as weight.

hmmm... I was thinking of mass. The problem still is pressure (force/area) and the impulse applied during a crash.

 

[KIAman]

The reason why airbags work so fast is because it is formed in 1/25th of a second using an explosive charge. It has to be fast to sufficiently protect the occupant in time when crashing. With something as massive as gel (or anything more solid than gas), you would be hard pressed to form anything fast enough to protect the occupants.

 

[Howard]

http://www.youtube.com/watch?v=7gtAsENBOcA (inside the first minute)

 

[Cogman]

Originally posted by: KIAman
The reason why airbags work so fast is because it is formed in 1/25th of a second using an explosive charge. It has to be fast to sufficiently protect the occupant in time when crashing. With something as massive as gel (or anything more solid than gas), you would be hard pressed to form anything fast enough to protect the occupants.

My thoughts exactly. The process might work, but it would be near impossible to get it out fast enough.

Not only that, but we need the give of air to absorb impacts, hitting the dry gel might be analogous to running into a brick wall.

 

[Gibsons]

Originally posted by: adlep
6. Because the material is very brittle, it would be quite easy to dismantle it quickly.
Should I proceed with the idea?

If it's brittle, how is it going to expand and maintain integrity?

 

[CycloWizard]

Originally posted by: Cogman
My thoughts exactly. The process might work, but it would be near impossible to get it out fast enough.

Not only that, but we need the give of air to absorb impacts, hitting the dry gel might be analogous to running into a brick wall.

Originally posted by: Gibsons
If it's brittle, how is it going to expand and maintain integrity?

Both of these questions have the same answer. A brittle material could fracture when your body collides with it. Depending on the type of gel, its fracture energy could be very large. Thus, it absorbs a very large amount of energy during fracture, thereby preventing tissues like your brain from absorbing that energy. Air is actually a relatively poor damping material due to its low viscosity, but it is used because it's better than a steering wheel.

 

[Gibsons]

Originally posted by: CycloWizard

Originally posted by: Cogman
My thoughts exactly. The process might work, but it would be near impossible to get it out fast enough.

Not only that, but we need the give of air to absorb impacts, hitting the dry gel might be analogous to running into a brick wall.

Originally posted by: Gibsons
If it's brittle, how is it going to expand and maintain integrity?

Both of these questions have the same answer. A brittle material could fracture when your body collides with it. Depending on the type of gel, its fracture energy could be very large. Thus, it absorbs a very large amount of energy during fracture, thereby preventing tissues like your brain from absorbing that energy. Air is actually a relatively poor damping material due to its low viscosity, but it is used because it's better than a steering wheel.

I get that, it can break one tiny piece at a time. There are some foams used for planting that are like that. They aren't elastic but can absorb energy as they get crushed bit by bit.

But how do you take a brittle material, pack it into a very small space (steering wheel) and get it to expand its volume... something like a hundredfold(?) and still be in one piece (or big enough pieces) to absorb the impact.

 

[CycloWizard]

Originally posted by: Gibsons
I get that, it can break one tiny piece at a time. There are some foams used for planting that are like that. They aren't elastic but can absorb energy as they get crushed bit by bit.

But how do you take a brittle material, pack it into a very small space (steering wheel) and get it to expand its volume... something like a hundredfold(?) and still be in one piece (or big enough pieces) to absorb the impact.

I'm not saying I know how, or that it's even possible - I don't know how or if it's possible. I'm just trying to clarify the ideas that I think the OP had.