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  • Today we're going back to school and New York University's Polytechnic Institute.

  • We're gonna check out a materials lab where we're gonna find out a,

  • how new materials get made and b, how we can destroy them.

  • My lab works on developing lightweight materials.

  • But these materials are intended for use in transportation applications to reduce

  • weight, and increase the safety of the passengers.

  • I'm Associate Professor in Mechanical and Aerospace Engineering, and

  • I direct the Composite Materials and Mechanics Lab.

  • The material that we work with, we call it syntactic foam.

  • It's because we fill these tiny hollow particles

  • inside our material to get the porosity.

  • If you don't have the tiny hollow particle,

  • you just make a material porous just like your kitchen sponge.

  • It doesn't have any strength and it also absorbs a lot of water.

  • You want something which is stiff,

  • which is lightweight, which is also strong of the same time.

  • It looks like the surface of a moon, just to give you an analogy.

  • We have facilities to characterize materials in a wide variety of loading

  • conditions, which include compression, tension, bending and

  • even very high speed compression and impact.

  • Experiments are fun but they are fun only until you break the material.

  • That felt good.

  • And we're here in front of the Hopkinson Bar machine.

  • What does this machine do?

  • This machine does very fast compression, like bomb blast or

  • car accident type situations.

  • And it compresses a small specimen.

  • We get all the data, then we can compare the results with slow compression and

  • see if property or failure are different.

  • Not many people have this machine.

  • You have to build it.

  • It's not a commercial machine.

  • We are about to destroy a very small piece of syntactic foam.

  • Dr. Gupta says that there's no real danger, unless I put my finger in front of

  • the bar, which is gonna be blasted at us very quickly.

  • So now I'm going to open the wall, and you'll hear a loud boom.

  • This is what's left of the fragment.

  • It looks okay if you kind of look at it from head on, but

  • it's definitely like really destroyed.

  • So this is the sample.

  • What's this?

  • This is the same piece that you just did.

  • This again, a broken particle.

  • Our projects have been funded by Army and Navy for many years.

  • And one example is USS Zumwalt,

  • the latest Navy ship whose deck is made of syntactic foams.

  • And this is the first composite ship.

  • There are many commercial applications right now.

  • In cars, one of the reasons you want to use foams is that in case of accidents,

  • they absorb a lot of energy and they save the passengers inside.

  • But when you reduce the weight,

  • you increase the fuel efficiency on top of every other technology.

  • So that's the benefit of lightweight materials.

  • All the challenges that we have in research, we have to meet the targets

  • where these materials can be strong enough and people have enough confidence in them

  • to use in real applications, but getting to that level is very difficult.

  • When I first made my first composite slab, it was really exciting.

  • You know, I just couldn't sleep that night.

  • So what do you do on a day-to-day basis when you get here?

  • Well research is a big part of life in University,

  • so most part of the day actually goes in working with research students.

  • And when you have these new novel materials,

  • sometimes we have no idea what properties would come out.

  • And whatever we learn in lab through our research today,

  • that's gonna be mainstream information tomorrow anyways.

  • I think that's an important part of the life.

  • When I'm in this room, I'm always looking at these machines and

  • trying to see what our next step might be.

  • I think future of materials science is very bright, and

  • mainly because the limitation of current technologies is

  • mainly the availability of right materials.

  • We don't know where will we get our materials from.

  • And space explorations provide a possibility of getting materials from

  • other planets.

  • So this will go farther quite a way.

Today we're going back to school and New York University's Polytechnic Institute.

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B1 中級 美國腔

世界上最堅固的保麗龍工程 (Engineering The Strongest Foam in the World)

  • 38 2
    張育崧 發佈於 2021 年 01 月 14 日
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