Security Walls
Dean
This is actually not a "stupid video" at all, it's a film of a test of a special type of security wall used around some military installations and embassies in rough parts of the world, and around chemical plants that have the potential to explode causing massive damage. I believe the primary company that makes them is Metalith Exteriors.
Just look at how impressive the physics are in that video. That's quite a few tons of robot-controlled truck, slamming at very high speed into the wall, and look how the wall barely budges. Impressive, no?
Update: According to the bottom of this page, under "features and benefits, these walls require "no footings as they are surface-mounted." (Thanks Peter.)
I wonder how deep they set the foundation for that wall?
Or maybe they've some sort of anti-gravity device that repells the truck just before contact.
If they're based on the same sort of concept as kevlar, it might be that a foundation would hamper performance. I'm thinking the principle here is that any impact tends to spread the force across as much of the wall as possible. So it has to be able to yield somewhat while spreading the force as far as possible.
I'm pretty sure that the dominant design here is, it's designed in such a way that whenever a particular point experiences an impact, that impact's force is spread across the entire rest of the structure. Sort of like, if I punched you hard in the solar plexus with 500 pounds of pressure in a 2 centimeter impact you'd be devastated, but if you had this little ring around your midriff that gave a little to that punch but effectively distributed 95% of that punch around your entire midriff it would feel like a gentle shove with a slight constriction around your chest.
Not unlike air pressure: 15 pounds per square inch is nothing, like putting little 5 pound weights all around your chest while you lay down. Nothing, right? A little uncomfortable maybe. 150 pounds centered right on your weakest point would be excruciating.
I'm thinking that's the principle here, and that's probably why the foundation wouldn't help much either way.
Take a firecracker in your open palm and set it off. Your hand stings and maybe you get a blister. Clench your fist aound a firecracker and set it off, and your wife is helping you open ketchup bottles for the rest of your life.
I'm thinking it's more like that.
(50 points if you can name the stupid movie I got that analogy from.)
Chain mail works on the same principle if a little more primitively.
As I say, I'm guessing but I'm betting it's the same principle. Smart design and advanced materials can do wonders. I'm betting that a firm foundation might actually just f*ck up the scenario.
I'm just a geek who's blathering. But I'll bet I'm more right than wrong on this. But hell, I'll just keep going since I'm on a wild hare anyway:
One of the weaknesses of kevlar vests turns out to be that while they can absorb enormous impacts--like a .45 automatic slug fired at close range--they are actually vulnerable to certain types of low-velocity attacks. There are bulletproof vests that can absorb a magnum slug at close range, but which you can stick a knife through by hand without much trouble. I'd wonder if a wall like this has a similar vulnerability.
But I'm still just guessing. ;-)
Sorry, I never noticed that. YouTube doesn't do that.
"Armageddon"
And your premise that the design is spreading the force along the full length of the wall is plausible.
Pretty cool.
Such a stupid, stupid movie. But so, so much fun. Great concept, lousy execution. At least if you're a science geek like me.
Personally, I like the first 45 minutes and then I lose interest once they get into space and the physicis become completely impossible. But I've had others disagree and tell me the last 45 minutes were the best. So it goes.
In any case, you can redeem your 50 points at Zombo.com, Sean. For whatever you wish. Try not to spend it all at once.
I'm thinking it's more like that.
(50 points if you can name the stupid movie I got that analogy from.)
It comes from the movie Armageddon. An explanation of how what blowing up an asteroid has to do with a firecracker.
But in spite of that, Armageddon was fun. I've always found Bruce Willis to be a pretty tolerable action hero. I think it was the first movie I saw Liv Tyler in. I still can't believe that came from Steven Tyler's loins.
Another movie science geeks love to hate that I enjoyed immensely was "Independence Day." Yes I know it is absurd that some super-nerd could write a virus and upload it to an alien computer. Of course that's stupidity of a monumental order (which means typical of Hollywood's concept of comptuers and technology, a concept that is indistinguishable from their concept of magic) but the movie is fun.
On the other hand, the movie I love both as movie fan and science geek is "BladeRunner." THE best sci-fi movie of the past 40 years. (Just to set the ground rules here, "Star Wars" was not science fiction. It was fantasy, pure and simple, complete with magic-wielding wizards who manipulated the fundamental "force" of the universe... I call it "Space Opera" or "Space Fantasy".
Some other true sci-fi movies are:
1. The Day the Earth Stood Still
2. Forbidden Planet (love that movie)
3. Robocop (yep, horrible movie, but true sci-fi)
4. Terminator (not a bad movie, either)
5. Predator (aliens hunting humans on earth? classic sci-fi scenario from the 50s).
But BladeRunner tops them all.
I actually didn't care that much for Jurassic Park. It was a major leap in computer animation, but the story was pretty lame, the acting was less than stellar and I don't think I've ever seen a movie with Jeff Goldbloom where I liked him. What Geena Davis saw in him is a mystery to me (except maybe his height).
Geena now, that's another story...
The jet disintegrates.
I like to send that one to those people who wonder where the plane that hit the Pentagon went.
Are you kidding me? Jeff Goldblum is one of my geek heroes, partly because he won over Geena Davis. I figure that gave hope to geeks everywhere!
Well, I did say "one of" my geek heroes. But Mr. Goldblum has played sympathetic geeks in enough roles to win him some geek loyalty, at least here and among friends of mine. He spews technobabble in a very convincing way, and he gets the girl.
Heh.