Super Strong Metal Foam Discovered 367
MikeChino writes to tell us that a North Carolina State University researcher has discovered what appears to be the strongest metal foam yet, capable of compressing up to 80% of its original size under load and still retain the original shape. The hope is that this amazing material could be used in cars, body armor, or even buildings to absorb the shock from earthquakes. "Metal foam is exactly what you might think – a cellular structure made from metal with tiny pockets of space inside. What makes Rabiei’s metal foam better than others is that she’s been able to make the tiny pockets of space more uniform. And that apparently is what gives it the strength as well as elasticity it needs in order to compress as much as it does without deformation. Many tests are being performed in the laboratory to determine its strength, but so far Rabiei says that the spongy material has 'a much higher strength-to-density ratio than any metal foam that has ever been reported.' Calculations also predict that in car accidents, when two pieces of her composite metal foam are inserted 'behind the bumper of a car traveling at 28 mph, the impact would feel the same to passengers as an impact traveling at only 5 mph.'"
Uniform fab (Score:2)
Re:Uniform fab (Score:5, Insightful)
Uniformity is one of the hardest things to accomplish when manufacturing anything. If it were easy, then first pass yield would be 100% every time. In reality, you are lucky if FPY reaches 95%, and if you've ever been in quality control, you know that 95% FPY is shit depending on the industry. If you aren't above 99% your nothing.
This is especially important and difficult in metallurgy. This is why there are highly trained material scientists and metallurgists working in the Aerospace industries. A well designed part is worthless if the heat from the tools changes the metal properties at the joints.
To go back to TFA, how would you suppose you form a foam out of metal? Now how you you ensure consistency?
I don't know, and neither do you. That's why it's a breakthrough.
Re: (Score:2)
A well designed part is worthless if the heat from the tools changes the metal properties at the joints.
Annealing and heat treating?
I don't know, and neither do you. That's why it's a breakthrough.
No, that's why neither you, I, nor oldhack are metallurgists. "I don't know and neither do you" is like two chemists agreeing that a bubble sort is a breakthrough because neither one of them know how to write computer code. Yes, it's a breakthrough because they found a way to do it better, with a corresponding improvement in the properties of the final product. However, I took oldhack's post to mean, "what was the breakthrough that allowed them to achieve grea
Re: (Score:2)
Random side note. I mentally swapped FPY into PFY, or pimply faced youth. One of the main characters in the Bastard Operator From Hell. Which is the single greatest collection of stories about IT workers abusing users.
Re: (Score:2)
Re:Uniform fab (Score:4, Funny)
He's asking "what is the breakthrough," not "what is a breakthrough," which is a small difference, but crucial. What changed about the process, or in the concept behind the process that allowed the breakthrough to happen. That's the question posed.
I suppose with your smartass answer, you're used to being able to coast through limited reading comprehension through application of "humour."
Re: (Score:2)
Do it in your basement, or don't claim that you could do it in your basement.
If I had a nickel for every time someone assumed that something they don't know how to do must be easy...
Replacement for air bags? (Score:2)
Re: (Score:2)
Re: (Score:2)
Um... ::facepalm::
Whoosh?
Re: (Score:2)
Re: (Score:2)
Or he thinks it can be used in the crumple zones and remove the need for an airbag. I mean, did you even bother reading the article summary? Whoosh, indeed.
Re:Replacement for air bags? (Score:5, Informative)
I read it as his desire to use this foam as a replacement for the bumper and crumple zones. It would turn the existing crumple zones into something in the car's frame and bumper system that would absorb a great deal more of the impact and, therefore, largely eliminate the need for airbags.
I'm not sure I'm buying it, though. Airbags are an "also need" feature, and cannot be replaced wholly by a better crumple zone.
The problem lies in the elasticity and the distance. If you hit a brick wall doing 65MPH and your crumple zone is too squishy, it will continue crumpling up until you are included in the crumple zone. In other words, you're dead.
Make it too hard, and the car will stop more quickly than your flesh can handle. The airbag is a crude but effective way of allowing a relatively stiff crumple zone that can manage to keep your passenger cabin intact during a VERY major impact, and still accommodate your body's need to decelerate as gradually as possible. If you hit a brick wall doing 65MPH, the crumple zone decelerates the car from 65MPH - 0MPH in the distance represented by the zone (usually a few feet at best), and materials aren't going to improve on that a whole hell of a lot. You are still going from 65MPH-0MPH in just a few feet. That's a SERIOUS amount of deceleration.
The airbag is what takes your head and torso and slows them down as gently and slowly as possible, leveraging the deceleration already provided by the crumple zone and making the best use of it to keep your brains from splashing around in your noggin, and/or snapping your neck. Which is not to say the airbag is gentle or slow at all, far from it, just more gentle and slower than making your dainty neck bones absorb all of the force as your torso is stopped by the seatbelt and your several pounds of head really wants to keep going to make Newton happy.
Could be worse, though. You could be wearing no seatbelt at all and expect your chest and head to absorb all of the speed when they impact the steering wheel and windshield respectively. That always ends colorfully, particularly in shades of red and grey.
Re: (Score:3, Informative)
When they develop an airbag that can detect your position and avoid punching you in the face, I'll want one. I had one in my Subaru and was always thinking about replacing the steering wheel and getting rid of it in the process. Neither of my vehicles have them and I like them that way.
If you really care about safety, the thing to do is to wear a helmet and a five- or six-point harness (males prefer six) when driving. The helmet is there not so much to protect your head as to give you a place to mount a hea
Re:Replacement for air bags? (Score:5, Interesting)
Re: (Score:3, Informative)
Well, and elastic just describes it's tendency to return to it's original shape, it says nothing about how much energy it's going to take to make it change shape in the first place...We're talking about a block of aluminum filled with hollow steel balls here. Anything short of a sledgehammer isn't going to change it in the least.
Re: (Score:3, Insightful)
As well as delicious.
Re: (Score:3, Informative)
Maybe, maybe not. Elasticity is not the same thing as softness... steel is pretty elastic, but you don't necessarily want a face full of it in a car wreck.
Correct. For an example, take a large steel ball bearing and a solid rubber ball the same size. Drop them on a concrete floor from the same height.. The steel ball, being more elastic than the rubber(!) will bounce higher.
The ability of a metal to deform under compressive stress is malleability (the counterpart of this is ductility, which is a measure of tensile stress). Elasticity is an entirely different 'ticity.
Re:Replacement for air bags? (Score:5, Informative)
You'd rather have a big hunk of metal than an airbag? Don't let the "foam" fool you: slamming your face into a block of it at 35mph would only be a little better than running face first into a brick wall at the same speed.
It's squishy and springy...for metal. But it's not what you'd call soft.
Re: (Score:2)
I'm not sure I agree. I've been in collisions where the vehicles involved were moving at about 20 or 25 mph, and the speed was too low for airbags to deploy. In both cases the vehicles involved were nearly destroyed and none of the occupants were hurt. If you're moving fast enough in a collision that an airbag deploy
Re: (Score:2)
Re: (Score:3, Informative)
This stuff is nice, but it's a mistake to look at it as a drastic improvement in terms of safety.
The benefit of this is the reduction in weight without loss of strength.
Re: (Score:3, Informative)
For a steering column, you want a structure with very high torsional stiffness, but very low longitudinal stiffness. You don't want it to deform at all when you turn it, but if it's compressed along its length, it should do so readily.
I believe today's steering columns already do this to some degree.
Re:Replacement for air bags? (Score:5, Interesting)
Airbags and bumpers serve two entirely different purposes.
If this material lives up to the hype (unlikely), your next car will feature both items.
I'm curious to know more about the 28mph -> 5mph assertion. That stat was given to the media because it sounds impressive (grant guff), but how does it compare to the deceleration of a traditional auto bumper.
Re: (Score:2)
I'm curious to know more about the 28mph -> 5mph assertion
I flat out disbelieve it. Extreme claims need extreme proofs.
Re: (Score:2)
The national standard is for a wimpy 50% reduction (5mph->2.5mph); this isn't the maximum by any stretch, since obviously you can put enough crap on the front to reduce the impact by 99% if you want to. So it's hardly an extreme claim.
The origin of the 28->5 number should be obvious. The material can compress to 80% of it's original size under load.
Re: (Score:2)
Perhaps she wasn't comparing the 28mph to a 5pmh with current bumpers, but a 5mph perfectly inelastic collision? Can't tell for sure.
Re: (Score:2, Insightful)
I think I'd rather have some of this between me and a potential impact than a classic airbag, if it came to the crunch. What do they use for an inflation gas generator - sodium azide is it? Nasty stuff. Like driving around with a firecracker held in front of your face.
I'm thinking if your face is traveling at 80+ kph into metal foam there is a going to be a lot of crunch going around. Airbags made of cloth and gas which deflate when you hit them do enough damage. I'd be more concerned with inhaling the fragments of my teeth and skull that resulted from my face colliding with a metal "pillow" than about inhaling the byproducts of the airbag detonation.
Reinforced... (Score:2)
...for the downstairs neighbor's protection.
A bit more detail here (Score:5, Informative)
Body Armor (Score:5, Insightful)
Re: (Score:2)
Unless the guy firing it gets knocked on his ass your own shock will be the only thing knocking you on yours...
Re: (Score:2)
Re: (Score:3, Informative)
Also a bullet has anywhere from 8-18 inches to accelerate, a vest has to stop it in usually less than 2.
Which is irrelevant. Total momentum transfer is what knocks you over (or not), not peak force--it's the integral under the curve, not the peak of the curve that matters.
A bullet has a mass of 10 g or so--up to 30 for really big guns. It travels at around 500 m/s. That's 0.01*500 = 5 kg*m/s momentum, enough to impart a velocity of 0.1 m/s to a 50 kg (very light) person or 0.05 m/s to a 100 kg person (qu
Re: (Score:2)
Re: (Score:3, Interesting)
The total impact energy (and momentum) of the bullet is constant regardless of vest type.
Lighter vests may not be able to spread the force of the impact over as large an area, so may be more likely to cause bruising.
In any case, the person firing the gun (assuming they're hand-holding the gun rather than having it fastened to something rigid) will need to absorb more energy/momentum when firing the gun than the target will when hit by the bullet. (Because the bullet is slowed slightly by air resistance.)
Th
Re: (Score:2)
Place this behind an existing body armor compound (one that stops the bullet) and use the foam to absorb the remaining shock.
http://en.wikipedia.org/wiki/Spalling [wikipedia.org]
Probably would make a nice spall liner for tanks.
Re: (Score:3, Interesting)
Re: (Score:2)
FWIW, I think we're a long way away from metal foams being used as personal body armor. Yes, they'll absorb some of the energy, but they'd still be bulky and heavy.
Vehicular armor is a much more likely use with the foams we have today.
Re: (Score:2)
Actually, they use steel and ceramic plates behind the kevlar even now, so you could switch out those and maybe see an improvement in protection to weight.
Re: (Score:3, Interesting)
The problem is the use of the word 'absorb'.
You aren't going to absorb it in any useful amount, you have to spread it. The energy HAS to go somewhere.
People aren't really thrown back, they are knocked off balance because they weren't prepared for the energy imparted on them. If getting shot actually 'knocked you back' it would do the same to the person firing.
Body armor just helps spread the force across a larger area. Your body is pretty damn resilient, but when you rich the breaking point it just falls
YouTube videos (Score:5, Informative)
Two youtube videos about the material:
http://www.youtube.com/watch?v=mI5ZzfOlbKA [youtube.com] - earlier video
http://www.youtube.com/watch?v=wfFcs25KmMc [youtube.com] - one week old video
Shows among other things compression tests of the material.
Grammar? Writing? Editors? (Score:2, Informative)
We just griped about that.
>capable of compressing up to 80% of it's original size
"It's" == "It is." No exceptions.
The genitive of "it" it "its."
Sincerely,
Grammar Police greetings from somebody for whom English is the 3rd language.
Re: (Score:2)
The reason people do this is because they remember the rule that possessives use apostrophes, but forget that some possessives don't.
He's, she's, it's (contraction)
His, hers, its (possessive)
Collision (Score:2)
Yeah, try that without a seatbelt or airbag then. You'd still be crushing your chest into your steering wheel at 28 MPH, unless this stuff also generates a star trek inertial dampening field.
Re: (Score:3, Interesting)
In 1976 I was driving a 1974 Gremlin at 50 mph, and had a head on collision with a quarter ton pickup truck that was doing 70. Back then they didn't even have padded dashes, let alone airbags; it was naked steel. I wasn't wearing a seat belt. I bent the steering wheel, and bent the dash where my shoulder hit it. The shoulder was permanently dislocated, but I had no organ damage (well, I may have suffered a concussion) or broken bones.
After the wreck you couldn't even tell what kind of car it was. I'll tell
Apollo Lunar Lander gear shock absorption system (Score:3, Interesting)
This material reminds me of the lunar module's landing gear, made out of collapsible aluminum honeycomb. Look here for the word aluminum [teamfrednet.org]. Highly interesting.
Re:How is it made? (Score:5, Funny)
Some hot metal, a tiny straw, and a guy who's really good at measuring his breaths.
Needless to say, scaling is a problem.
Re: (Score:3, Funny)
Think China, lots of guys, lots of straws.
Re:How is it made? (Score:5, Funny)
Damn, and we already shipped all of our tiny straw manufacturing over to China!
Re: (Score:3, Funny)
Nah. All you need is a straw-transistor: You blow in a small straw, which controls a huge turbine, blowing out of a bazillion straws into a bazillion glasses of fresh metal milk.
Re:How is it made? (Score:5, Informative)
The foam is made by filling a mold with hollow steel spheres and then filling the gaps with molten aluminum. VERY scalable.
I wonder how it would fair if, instead of using molten aluminum to fill the gaps, you coated the steel spheres with aluminum (or other binder that melts at a temp lower than the spheres would start to collapse at) and sintering it into a solid block. More air gaps means it's lighter, but still very uniform.
=Smidge=
Re:How is it made? (Score:5, Informative)
The foam is made by filling a mold with hollow steel spheres and then filling the gaps with molten aluminum. VERY scalable.
Well, yeah, if you assume hollow steel spheres are "off the shelf". Kind of like saying starships are very scalable, you just make them with warp drives, problem solved.
I have cast aluminum and have had porosity problems. Basically some gasses dissolve better in hot aluminum and bubble out as it cools. Preventing porosity in castings is very old technology. I always assumed metal foams did the opposite of preventing porosity, and tried to supersaturate molten metal with hydrogen or argon or something under pressure and then froze it at a rate that grew the bubbles to just the right size. Metallurgists have no problem doing all kinds of complicated heat treatments and all kinds of weird alloys, so I figured the limitation was dissolving enough "whatever" in the metal to make it work.
Re: (Score:2)
When you say small metal spheres, it makes me think of stealth technology. If I remember right, the "radar absorbing coating" contains small metalic spheres that cause the radar signal to be diminished as it is dispersed into the medium and begins bouncing off the spheres.
So, I have to wonder, if a layer of this material would have a similar effect for reducing your radar signature. If so, that plus a laser jammer (legal in most states for non-commercial vehicles) would make for a pretty sweet rig.
-Steve
Re:How is it made? (Score:5, Interesting)
You know what’s ignored and missing in this discussion?
The question of what the spheres are filled with!
Because they are certainly not “filled” with a vacuum.
But I think there got to be cool properties and applications, when you fill them with something else than air.
Re: (Score:2)
"It's the bubbles of nothing that make it really something".
Re:How is it made? (Score:5, Informative)
Re:How is it made? (Score:5, Insightful)
Geroge Carlin (Score:5, Funny)
George Carlin used to point out that if you put a large spike on the steering wheel so that the driver would suffer badly in a collision, the numbers of collisions would drop dramatically.
Re: (Score:2)
Re:Geroge Carlin (Score:4, Insightful)
Using a primary plus two secondary means of birth control can help (condom + pill + rhythm method)
Seriously, though... some accidents simply cannot be avoided. Sometimes a driver is faced with a choice of accidents... get sideswiped by a moron or run off the road. Sure, there are things you can do to minimize accidents (like don't drive in someone else's blind spot), but the only way to assure yourself that you will never get in an auto accident, no matter how careful you are, is to not ever get into an auto.
That said -- I've been in two accidents in my life (both when I was 17 with less than a year's driving experience), and I could have avoided both if I was as experienced as now, by not putting myself in a situation with no escape. And if I'd been weeded out of the gene pool at age 17, then humanity would have suffered a great loss*.
*YMMV. Some may say that humanity would have escaped great suffering. It depends on how my plans for world dominat^H^H^H^H^H^H^H leadership progress.
Re:Geroge Carlin (Score:4, Funny)
but the only way to assure yourself that you will never get in an auto accident, no matter how careful you are, is to not ever get into an auto.
That's not true. You can still get hit by a car while riding your bicycle or walking on the sidewalk. Not getting into a car doesn't keep you safe from cars.
The best way I can think of to assure yourself you will never get into a car accident is to shoot yourself in the head.
Or jump off a bridge or a cliff so they don't find your body and get into a car accident on the way to the morgue.
Re: (Score:2)
Aww, you got me there. How about if you never leave your mom's basement, and you arrange your furniture on the side of the basement away from the street? Would that work?
Or perhaps drive a six-inch spike through your head?
That is no
Re:Geroge Carlin (Score:5, Funny)
Aww, you got me there. How about if you never leave your mom's basement, and you arrange your furniture on the side of the basement away from the street? Would that work?
Sorry. Off-road vehicles approaching from the middle of the block. Cars dropped from the back of transport aircraft and crashing through the roof and all intervening floors. Cars experiencing a freakish (vanishingly unlikely, highly improbable, probably only going to happen if someone triggers an Improbability Drive without shielding) spontaneous quantum teleportation from the street into the basement.
It's like the Golden BB... if your number is up, it's up.
I would imagine the best way to avoid a car accident is to have never been conceived. After all, for some people, having been conceived was itself a car accident.
Re: (Score:3, Funny)
You really want to be on the same side of your mom's basement as the street. If a car approaches at a good speed, it's going to land on the opposite side of the basement.
Re: (Score:3, Informative)
Okay, let's play out a scenario here.
You are at a stop light in the middle lane, with a vehicle in front of you and vehicles on both sides of you. It is winter time, and the roads are slick. A vehicle coming up behind you skids on the ice and cannot stop in time. You are boxed in by all the other cars on the road and cannot go anywhere.
Kindly explain how you are going to "avoid" this collision.
Re: (Score:3, Insightful)
Hmm, so everyone who lives north of Georgia and actually has to leave their basement is too stupid to live. Actually, I kinda like that *evil grin*
But then, I live in Florida, where I run the risk of hydroplaning during an afternoon rainstorm 8 months out of the year. So maybe I'm too stupid to live for not being smart enough to call in sick 120 days a year because I might have to drive home in the rain =)
Maybe we're all too stupid to live.
Re:Geroge Carlin (Score:5, Funny)
Maybe we're all too stupid to live.
You just summed up Carlin's work in that one sentence.
Re:Geroge Carlin (Score:5, Insightful)
Riiiight. Because in the real world, there are only 5 other vehicles on the road at any time. Roads are way too congested to actually leave enough room to change lanes in a case like this.
Nevermind the time requirement. Safely changing lanes safely in a short distance on sub-optimal road conditions requires a nontrivial amount of time. Which you may/may not have depending on when the vehicle behind you begins to skid.
You can takes steps to *minimize* the risk, but some accidents simply cannot be avoided.
Re: (Score:3, Insightful)
Nice missing his point, dingbat. There would be no way of avoiding that situation, and an otherwise fender bender that would not cause injury would result in your death.
Re:Geroge Carlin (Score:5, Insightful)
Accidents, including accidents that are not your fault, can be avoided.
Normally, I try to be constructive and polite but sometimes there is a need to make an exception.
Don't you hate it when you post something really stupid on slashdot and you can't unpost it?
Or are you aware of some precognitive ability that I am not?
Something that would have told myself and a few others to pull to the side of the road rather than stop in the lane for heavy traffic on I95 to allow the driver that fell asleep to pass us by harmlessly? You know, rather than plow into the back of my truck, into another vehicle and finally into a third?
They had to cut the roof off to get me out. So if you have figured out some magic way I could have avoided that I, and I'm sure a heck of a lot of other people, would really like to know.
Re: (Score:3, Funny)
Or are you aware of some precognitive ability that I am not?
Yeah, I thought it was common knowledge! Tom Cruise was advertising them a while ago.
Of course it's not terribly practical in most vehicles, having to carry around the three bathtubs for your precogs (you can try one but the accuracy goes way down). Plus the way they tell you things is pretty useless while driving. By the time the little wooden ball rolls down the machine and get carved, you look at it and it just says "You're about to die!" Th
Re: (Score:3, Insightful)
While precautions are necessary, you serve as proof against your own position when it is considered in it's entirety. For example, your precautions still failed you with regards to the drunk driver. Did you tell your employer or the police that arrived at the scene that you could have avoided the accident?
I'll never know what happened in the side-swipe, but the road was narrow and winding, so there's mitigating circumstances.
Where is that willingness to take responsibility? You focus on and downplay your own fault here and thus, by your own words "Some people, such as you, get focused on fault instead of responsibility. You ar
Re: (Score:3, Insightful)
Whilst I'm not saying it's your fault still, it's good practice to assume that people wont stop at stop signs even though they should.
In the UK we have lots of roundabouts, and I mean lots. The amount of people who incorrectly indicate on roundabouts is phenomenal. It's not always easy to tell if someone is exiting the roundabout or not, it should be easy to tell- they should just indicate and go off, but often they don't, sometimes they indicate to go off and then don't even. The point is, when pulling out
Re: (Score:3, Informative)
Yes. There are ways to minimize the chance of getting rear-ended at a red light.
1. Pump your brakes when a car comes into view in your rear-view mirror. Your flashing brake lights increase the chance the other driver will recognize the situation and stop in time.
2. Stop at least a car length before the white line at a stop light. I
Re: (Score:3, Insightful)
1. Might work, might not. No guarantees.
2. Might work, might not. It's a good suggestion but only works at intersections without sensors under the pavement. I've been at red lights that never go green until you pull up close enough to be detected.
3 & 4. Might work, might not. Just because some times are more likely to have unsafe drivers on the road does not mean you are guaranteed to be safe from them at other times. Also, not driving is not a solution to safe driving. Well it is, but it's not always p
Re: (Score:3, Interesting)
So you're that asshole who stops a car length in front of the white line and doesn't trigger the pressure plate half the time. Thanks asshole.
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
1960s and 1970s cars prove him wrong. Those vehicles had a high rate of impaling the driver on the steering column in a crash of high enough speed and the accident rates were no better.
Re: (Score:2)
It's not the mortality rate that would cause safer driving. It's the threat of the mortality rate.
It's much harder to ignore the threat of a large spike than of the steering column.
Re: (Score:2)
His being a comedian proved him wrong. Fractured logic == funny.
(Note to everybody about to hit 'reply': Yes, the 'irony' of my post was intentional.)
Re: (Score:2)
Re: (Score:2, Insightful)
I've heard it told that George Carlin was a comedian.
Maybe Geroge Carlin was a different guy that was a car designer, but I don't thing so, I think it was a typo.
Re: (Score:2)
But if everyone found out that they will die if they crash, they would take less risks.
Re: (Score:2)
I dunno. At worst, it shifts the kinds of risks they'd be willing to take.
"Oops, traffic ahead on the street has stopped suddenly, and it looks like I can't avoid hitting something."
Normal steering wheel: "Brake hard, hope the ABS works well, and trust to the air bag and the seat belts."
Spiked steering wheel: "Swerve onto the sidewalk to buy about another 200 feet of braking distance. Too bad for the pedestrians."
Re: (Score:2)
True, because the population would drop dramatically as well.
Re: (Score:2)
My response to that would be a liberal application of a hacksaw.
Re: (Score:2)
Really?
I'd use a plasma torch and save the labour.
Re: (Score:2)
In other words, calling insurance companies,
Yes
calling the police to file a traffic report,
Not usually
possible layer involvement?
Anything is possible. Though I'm not sure why a layer would care (unless I hit his brick truck).
Re: (Score:2)
It's funny how out-of-shape nerds that OD on Dr. Pepper and Cheetos and avoid outdoor activities often support survival of the fittest.
Re:NO NO NO NO NO (Score:5, Funny)
Au contraire! Some of the impact force will compress the foam, instead of compressing the child's head.
My testing has conclusive shown that a child's head, impacted at 25 mph by a block of this foam, will compress only 3 inches, compared to 5 inches when hit by a piece of solid aluminum.
Clearly this means that children will be 40% less dead when hit by a Canyonero driven by a soccer mom texting her neighbor's landscaper about getting her garden tilled*, provided that the Canyonero is equipped with this foam.
*And by getting her garden tilled, I mean having her bushes trimmed**
**And by having her bushes trimmed, I mean having bulbs planted***
****And by having bulbs planted, I mean having roots... oh screw it. I mean having a tryst.
Re: (Score:3, Funny)
Clearly this means that children will be 40% less dead when hit by a Canyonero
That might be enough for Miracle Max to work with!
****And by having bulbs planted, I mean having roots... oh screw it. I mean having a tryst.
I'm still confused... What's a tryst? Are they perennials? What's this landscaper's number, I think I could use a tryst or two.
Re: (Score:2)
I think it's like a cyst, only three times as much.
I got this from etymonline.com:
late 14c., from O.Fr. tristre "appointed station in hunting," possibly from a Scand. source (cf. O.N. treysta "to trust;" see trust).
So I think maybe she has a furry rodent (perhaps a muskrat or beaver) she needs the gardener to take care of with his big gun.
Re: (Score:2)
Hmmm, now I'm thinking I'd be more interested in the woman's rodent than the gardner's gun. I don't like guns, they make me feel nervous and awkward as I try not to look at them.
Re: (Score:3, Interesting)
It sounds like a cool material, but the last thing we need is for something to make the idiot behind the wheel feel SAFER.
Oddly, the vehicles that make you FEEL safest are the most dangerous on the road -- SUVs. More people die in SUVs per passenger mile than any other kind of vehicle, and the reasons are simple. Their weight makes braking and handling problematic, their height makes handling problematic and rollovers easier, and they have no crumple zones. This stuff wouldn't make you feel safer, but it wo
Re: (Score:2)
It might be flame-ish, but some things don't add up. The force during impact is proportional to the acceleration from impact speed to zero. For a perfectly designed bumper, the acceleration (change in speed) will be linear from initiation of impact to zero speed.
Here's the rub - most impact at 28mph is likely going to be absorbed by the crumple zones in the fenders, not the bumper. The bumper is already going to compress at least 25-50% at impact and this is going to increase that to maybe 90% (I'm assumin
Re:Bullshit (Score:5, Informative)
Do you have physics to back you up? No, I didn't think so.
Take a new Toyota Tacoma. Assume weight savings in replacing bumper with foam metal is used elsewhere so you have the same mass vehicle. A Tacoma weighs approximately 4000 pounds, which is approximately 1800 kg.
Kinetic energy is given by:
e=0.5*m*v^2
m = mass
v = velocity (or speed for our purposes).
The kinetic energy of a Tacoma moving at 28 miles per hour is approximately 141 kJ.
The kinetic energy of a Tacoma moving at 5 miles per hour is approximately 4.5 kJ.
That is, the foam bumper only has to absorb 31 times as much energy as the solid bumper to perform to the quoted standard.
See quote below, which is from here: http://www.rexresearch.com/rabiei/rabiei.htm [rexresearch.com]
We see they estimate a factor of 80 improvement of energy absorption over the foam metal's equivalent bulk material. They don't say, but let's assume (reasonably) that they are talking about linear compression. Let's assume for a second that the stock bumper is made of a block of solid steel that doesn't absorb any energy. It's not, and it does, obviously.
If their estimate is correct, and a foam bumper of the same size will absorb 80 times as much energy as its solid counterpart, then the passenger in the 28 mph impact would feel 1-2 kJ of energy instead of ~140 kJ of energy. Obviously the bumpers are not solid metal, and they already have some energy absorption capabilities built into them.
Based on the factor of 31 between the kinetic energies of the vehicle at different speeds, I think their claim is the opposite of bullshit. It's reasonable.
Re: (Score:3, Informative)
Re: (Score:3, Informative)
100MPH+ crashes are fairly common in Formula 1. The driver almost universally survives. In fact, the last Formula 1 fatality happened in 1994. This material might be too heavy to work for Formula 1, but if it can give other cars a bit of the same safety, I'm all for it. If the car magically springs back into shape after a crash, so much the better.
you can try to bury the truth (Score:3, Interesting)
But moderation will not do the job. If you want me to stop telling the truth even over the objections of liars, you're going to have to ban me from slashdot.