字幕列表 影片播放 列印英文字幕 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.
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 更多分享 分享 收藏 回報 影片單字