WEBVTT - An Overview of Carbon Fiber 0:00:04.440 --> 0:00:12.360 Welcome to Tech Stuff, a production from iHeartRadio. Hate there 0:00:12.400 --> 0:00:16.480 and Welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:16.520 --> 0:00:21.320 I'm an executive producer with iHeartRadio. And how the tech 0:00:21.560 --> 0:00:26.799 are you. I'm back after my vacation and then the holiday, 0:00:27.440 --> 0:00:30.920 and we're ready to tackle some new episodes. And there 0:00:31.000 --> 0:00:34.879 have been a few really big events in the news 0:00:34.960 --> 0:00:37.680 over the last few weeks that have a tech angle 0:00:37.840 --> 0:00:41.919 to them. There's the ongoing war in Ukraine, which was 0:00:42.280 --> 0:00:47.040 punctuated by a brief but notable coup attempt in Russia. 0:00:47.680 --> 0:00:52.400 There's the ongoing chaos over at Reddit, which has had 0:00:52.400 --> 0:00:56.800 effects far beyond Reddit itself because companies like Google have 0:00:56.880 --> 0:01:00.480 struggled to deliver satisfying search results, while hundreds of popular 0:01:00.520 --> 0:01:04.920 subreddits either remain dark or cluttered with memes, or some 0:01:05.000 --> 0:01:08.120 of them are set to not safe for work status 0:01:08.160 --> 0:01:11.919 and so they're not showing up properly. And then there's 0:01:12.280 --> 0:01:16.759 the Titan submersible, the vehicle where five people perished when 0:01:16.800 --> 0:01:21.800 the submersible suffered a catastrophic failure. I thought today I 0:01:21.800 --> 0:01:25.880 would talk about something relating to that last story. Now 0:01:25.880 --> 0:01:27.560 I'm not going to do a full story about the 0:01:27.600 --> 0:01:32.160 systems aboard the Titan submersible, because a lot of other 0:01:32.200 --> 0:01:34.959 people have already done that to varying degrees. I've seen 0:01:35.040 --> 0:01:38.280 some treatments that were very high level. I've seen one 0:01:38.640 --> 0:01:42.840 really decent video that talked about the various systems. If 0:01:42.840 --> 0:01:46.120 you do want a deeper conversation about the Titan submersible, 0:01:46.440 --> 0:01:49.520 I will go into it. But I figure that because 0:01:49.520 --> 0:01:51.760 there's already all this coverage out there, and even by 0:01:51.840 --> 0:01:55.800 the time this episode goes out, you know, with news 0:01:56.000 --> 0:01:58.080 going as fast as it does, a lot of people 0:01:58.160 --> 0:02:01.120 would already say it's old news. So chances are you 0:02:01.200 --> 0:02:04.520 might already know everything there is to know already. But 0:02:04.600 --> 0:02:07.320 if you would like me to do an episode about 0:02:07.400 --> 0:02:11.600 the Titan submersible and its various systems and how it worked, 0:02:11.680 --> 0:02:15.200 let me know and I will be sure to tackle that. 0:02:15.800 --> 0:02:19.560 So instead, for this episode, I thought I would focus 0:02:19.720 --> 0:02:22.800 on one of the primary materials, not the only one, 0:02:23.120 --> 0:02:25.760 but one of the big ones used in the construction 0:02:26.000 --> 0:02:30.239 of the Titan submersible, which is carbon fiber. I figure 0:02:30.280 --> 0:02:32.800 we can learn about the history of this material and 0:02:32.800 --> 0:02:35.560 what makes it special, and a little bit about how 0:02:35.560 --> 0:02:39.440 it's produced and what applications benefit from it versus ones 0:02:39.480 --> 0:02:43.919 that perhaps are not ideal applications of carbon fiber, because, 0:02:43.960 --> 0:02:47.240 as it turns out, carbon fiber has a lot of 0:02:47.360 --> 0:02:52.440 really good legit uses and applications, but not all of 0:02:52.480 --> 0:02:57.000 them make sense necessarily. But let's start by talking about 0:02:57.080 --> 0:03:01.840 carbon itself, because, as the name implies, carbon fiber is 0:03:01.880 --> 0:03:06.280 made up of carbon. It is the sixth most plentiful 0:03:06.320 --> 0:03:09.840 element in the universe by the number of atoms out there, 0:03:10.560 --> 0:03:17.120 according to Encyclopedia Britannica. That is, it trails behind hydrogen, helium, oxygen, neon, 0:03:17.360 --> 0:03:22.840 and nitrogen. On Earth, carbon doesn't really rank that high 0:03:23.160 --> 0:03:25.840 as far as elements found in the Earth's crust. In fact, 0:03:25.840 --> 0:03:31.680 it makes up about point zero two five percent of 0:03:31.720 --> 0:03:36.040 the Earth's crust. Now, despite this tiny little pathetic showing 0:03:36.800 --> 0:03:40.080 on the Earth's crust, carbon is actually part of more 0:03:40.120 --> 0:03:44.440 compounds than any other element. It can make more compounds 0:03:45.000 --> 0:03:46.920 than any element you can think of. In fact, it 0:03:46.960 --> 0:03:51.760 forms more compounds than all the other elements put together. 0:03:52.560 --> 0:03:54.680 Not put together in a compound, but I mean, like 0:03:54.800 --> 0:03:58.280 all their various combinations that we have discovered. Now you've 0:03:58.400 --> 0:04:02.600 likely heard the fray, the carbon based life form. At 0:04:02.680 --> 0:04:06.280 least you have. If you've watched any science fiction, you've 0:04:06.280 --> 0:04:11.120 probably heard the phrase organic compounds. Well, an organic compound 0:04:11.280 --> 0:04:15.360 is one that contains carbon, and any compound that does 0:04:15.440 --> 0:04:22.039 not contain carbon is an inorganic compound. So why do 0:04:22.200 --> 0:04:28.359 scientists associate the words life and organic with carbon. Well, 0:04:28.400 --> 0:04:32.280 it's because of carbon's tendency to form multitudes of compounds 0:04:32.360 --> 0:04:36.159 at a range of temperatures that we find here on Earth. Right, 0:04:36.520 --> 0:04:40.960 not all elements will form specific compounds under Earth temperatures. 0:04:40.960 --> 0:04:44.279 You might have to go to extremes to create certain compounds, 0:04:44.279 --> 0:04:50.920 but carbon readily forms countless compounds here on Earth just 0:04:50.960 --> 0:04:55.080 in regular Earth conditions. Many of those compounds are polymers. 0:04:56.000 --> 0:04:59.839 Polymers are large molecules that are made up of repeated 0:05:00.200 --> 0:05:04.720 units that are chained together, and all living stuff on 0:05:04.720 --> 0:05:07.320 Earth has carbon in it. So the thinking goes that 0:05:07.360 --> 0:05:10.880 carbon is just so well suited for making all these 0:05:10.920 --> 0:05:15.000 different compounds at temperatures that we associate as being livable 0:05:15.000 --> 0:05:18.239 temperatures that, at least here on Earth, it makes sense 0:05:18.240 --> 0:05:21.960 that it's a foundational element for life. Now, whether that 0:05:22.080 --> 0:05:24.640 is true elsewhere in the universe is hard for us 0:05:24.680 --> 0:05:27.480 to say. We have a sample size of one planet 0:05:28.000 --> 0:05:30.080 that we know to have life on it, and we 0:05:30.160 --> 0:05:32.440 live on it. That's it. We don't know of any 0:05:32.440 --> 0:05:37.159 other planets. It's quite possible there are maybe countless planets 0:05:37.160 --> 0:05:39.520 that have life on them. We don't know about them. 0:05:40.160 --> 0:05:43.919 Carbon's utility and tendency to bind in molecular compounds seems 0:05:44.000 --> 0:05:47.560 to give it an edge over others. But science fiction 0:05:47.680 --> 0:05:51.839 is filled with examples of, say, alien civilizations that turn 0:05:51.880 --> 0:05:53.800 out to be life forms that are based on other 0:05:54.600 --> 0:06:00.440 elements like silicon. It's just that carbon. Because it's such 0:06:00.680 --> 0:06:04.560 an interesting element, and it does form all these compounds 0:06:04.640 --> 0:06:10.120 so readily under earthlike conditions, we figure this is probably 0:06:10.920 --> 0:06:14.440 a cornerstone for life, at least life as we understand it. 0:06:15.200 --> 0:06:19.960 Carbon is non metallic. You know, if you burn wood 0:06:20.040 --> 0:06:24.120 down into charcoal, that's carbon. That's the charcoal is carbon. 0:06:24.640 --> 0:06:27.320 If you squeeze it hard and hot and long enough, 0:06:27.760 --> 0:06:30.240 which sounds a bit racy, but if you do that, 0:06:30.720 --> 0:06:34.880 then obviously you get a diamond. Carbon's really neat. Depending 0:06:34.960 --> 0:06:37.880 upon its molecular arrangement, it can be soft enough to 0:06:38.000 --> 0:06:41.320 use as pencil lead that would be graphite, right, Like, 0:06:41.680 --> 0:06:46.880 that's soft enough where if you drag the lead across vapor. 0:06:47.400 --> 0:06:51.200 It leaves some of it behind, right, it's just the 0:06:51.240 --> 0:06:54.920 pressure of your hand pushing the pencil against paper is 0:06:55.040 --> 0:06:58.840 enough to rub some of the carbon off. That's graphite, 0:06:58.880 --> 0:07:02.039 But it could also be made into a diamond, which 0:07:02.080 --> 0:07:04.599 is hard enough to cut most other materials. Again, it's 0:07:04.600 --> 0:07:08.720 all in that molecular structure. How are those carbon atoms arranged, 0:07:09.360 --> 0:07:13.920 and that's what really matters. How do those carbon atoms 0:07:14.040 --> 0:07:20.480 form crystaline structures. That determines the features of the material 0:07:20.640 --> 0:07:23.840 that you end up with in aggregate, whether that's coal 0:07:24.280 --> 0:07:29.320 or charcoal or diamond or anything like that. So that's 0:07:29.400 --> 0:07:32.440 carbon in a nutshell. Well, obviously you could spend multiple 0:07:32.560 --> 0:07:35.280 university level chemistry classes talking about it. I mean, the 0:07:35.320 --> 0:07:39.840 whole branch of organic chemistry focuses on it. But for 0:07:39.920 --> 0:07:43.400 our purposes we're gonna leave off from there because really 0:07:43.400 --> 0:07:46.840 there's not much more to say about it when we're 0:07:46.880 --> 0:07:50.160 talking about carbon fiber. So let's turn our attention there. 0:07:50.720 --> 0:07:53.400 And by the way, first of all, if you're in America, 0:07:53.680 --> 0:07:58.360 you're probably spelling fiber fiber, and if you're a brit 0:07:58.400 --> 0:08:03.200 you're probably spelling it fiber bray I bre Now I've 0:08:03.240 --> 0:08:07.960 already mentioned that carbon can form polymers, these long chain 0:08:08.160 --> 0:08:12.840 molecules that have repeating structures in them. A carbon fiber 0:08:12.960 --> 0:08:16.440 is essentially a really really long one of these, or 0:08:16.520 --> 0:08:20.160 rather a tube made up of these carbon nanotubes, by 0:08:20.160 --> 0:08:23.440 the way, kind of takes the same concept, but down 0:08:23.480 --> 0:08:28.640 to the nano level. Anyway, carbon fiber material ends up 0:08:28.640 --> 0:08:32.280 being lightweight and strong. It can be electrically conductive. It 0:08:32.320 --> 0:08:35.880 can also be thermally conductive, depending upon the carbon fiber 0:08:36.160 --> 0:08:39.600 used in the process you use to produce it. We'll 0:08:39.640 --> 0:08:42.160 talk more about the qualities of carbon fiber in a bit, 0:08:42.200 --> 0:08:44.880 but before we get to that, let's talk about its 0:08:44.920 --> 0:08:50.280 actual history. The story of carbon fiber is fascinating and 0:08:50.559 --> 0:08:54.560 it involves the inventor of the incandescent light bulb. And 0:08:55.160 --> 0:08:58.160 some of y'all clever smarty pants out there already know 0:08:58.320 --> 0:09:02.240 I'm being coy because I am not talking about Thomas Edison. 0:09:02.520 --> 0:09:07.360 Thomas Edison did not invent the incandescent light bulb. Now 0:09:07.400 --> 0:09:10.320 here in America. One of Edison's many nicknames is the 0:09:10.360 --> 0:09:13.360 Inventor of the light bulb. But the truth is that 0:09:13.960 --> 0:09:18.240 Joseph Wilson swan over in the UK, beat Edison to 0:09:18.280 --> 0:09:20.880 the punch by a couple of decades, and he did 0:09:20.880 --> 0:09:23.840 it using carbon fiber as a filament, or at least 0:09:23.840 --> 0:09:28.160 eventually he did use carbon fiber. So we're talking around 0:09:28.200 --> 0:09:31.520 eighteen sixty here, and before figuring out how to make 0:09:31.640 --> 0:09:36.199 carbon fiber, Swan had started off with carbonized paper as 0:09:36.240 --> 0:09:38.920 the filament. So this is the stuff folks would use 0:09:38.960 --> 0:09:42.800 to produce copies from one document. You would have your 0:09:42.880 --> 0:09:45.920 primary document and that would be on the top of 0:09:45.960 --> 0:09:49.200 a stack. Right below your primary document would be a 0:09:49.240 --> 0:09:53.000 sheet of carbonized paper that is paper coated with carbon 0:09:53.080 --> 0:09:56.720 on one side the site that's face downward from the 0:09:56.760 --> 0:10:00.040 top page. And then the next layer would be a 0:10:00.240 --> 0:10:02.600 blank sheet of paper that would be your copy that 0:10:02.640 --> 0:10:05.920 you'd be creating. So if you wrote on the top document, 0:10:05.920 --> 0:10:08.800 it would put enough pressure on this carbonized paper to 0:10:08.880 --> 0:10:13.320 leave an imprint on the blank sheet below that, and boom, 0:10:13.360 --> 0:10:15.920 you get two documents for the effort of making one. Now, 0:10:15.960 --> 0:10:18.840 you could actually do more layers of carbonized paper than 0:10:18.960 --> 0:10:22.280 blank sheets, but as you go down the layers, the 0:10:22.320 --> 0:10:25.160 pressure that is being put on the paper is decreasing, 0:10:25.679 --> 0:10:28.680 so unless you're being super heavy handed with your writing, 0:10:28.760 --> 0:10:31.320 the bottom copies will be much more faint than the 0:10:31.400 --> 0:10:33.880 upper ones would be, so you have a limit to 0:10:33.880 --> 0:10:37.000 how many copies you can produce through this method. Anyway, 0:10:37.480 --> 0:10:40.840 Swan was using carbonized paper as his filament, so he 0:10:40.960 --> 0:10:45.720 was connecting pieces of carbonized paper to a pair of electrodes, 0:10:46.160 --> 0:10:48.960 and he encased the whole thing in glass and attempted 0:10:49.000 --> 0:10:52.480 to create a vacuum inside the glass and then zap 0:10:52.559 --> 0:10:55.080 the heck out of the paper using the electrodes. The 0:10:55.080 --> 0:10:57.480 paper would heat up to the point of glowing, but 0:10:57.600 --> 0:11:00.600 the lack of oxidizers in the glass meant it wouldn't 0:11:00.720 --> 0:11:04.080 catch fire, except the Swan couldn't get a perfect vacuum 0:11:04.120 --> 0:11:07.079 seal in. The carbon paper didn't last very long, nor 0:11:07.120 --> 0:11:09.400 did it give off much light, so it wasn't really 0:11:09.440 --> 0:11:15.280 a practical filament for an incandescent bulb. It worked in 0:11:15.320 --> 0:11:17.920 the sense that it would glow, but it wasn't bright 0:11:18.040 --> 0:11:19.760 enough and it didn't last long enough for it to 0:11:19.800 --> 0:11:23.080 have any practical use. So Swan wanted to find something 0:11:23.080 --> 0:11:25.760 else to serve as the filament in his incandescent bulb. 0:11:26.240 --> 0:11:29.280 He was also experimenting with some other stuff like nitro cellulose. 0:11:30.000 --> 0:11:33.520 This stuff is highly flammable, so flammable that at one 0:11:33.559 --> 0:11:36.080 time it was being used as propellant for firearms, and 0:11:36.120 --> 0:11:39.240 it was called gun cotton back in those days. Well, 0:11:39.240 --> 0:11:43.000 Swan figured out that he could push nitro cellulus through 0:11:43.760 --> 0:11:46.240 like a mesh with very small holes in it, and 0:11:46.280 --> 0:11:49.880 the nitro cellulus would form fibers as a result, kinda 0:11:50.600 --> 0:11:53.480 like one of those playto playsets where you push down 0:11:53.480 --> 0:11:55.880 on a lever and it squeezes your play doo through 0:11:55.880 --> 0:11:58.680 a grid of holes, so you can make I don't know, dayglo, 0:11:58.800 --> 0:12:02.920 pink spaghetti or what. Well what Swan did the nitro cellulose, 0:12:02.960 --> 0:12:08.640 he also tried with carbon. He took carbon and in 0:12:08.679 --> 0:12:11.040 the form of cotton fibers. In this case, he treated 0:12:11.080 --> 0:12:14.480 the cotton fibers with sulfuric acid and then he pressed 0:12:14.600 --> 0:12:18.400 this solution through a screen with tiny holes in it, 0:12:18.720 --> 0:12:20.200 and on the other side of the screen he ended 0:12:20.240 --> 0:12:22.600 up with carbon fibers, and he could curl those fibers 0:12:22.679 --> 0:12:26.440 up to make tight spirals, which would increase the amount 0:12:26.480 --> 0:12:28.880 of material that he could fit between a pair of electrodes. 0:12:29.280 --> 0:12:32.280 And the carbon fibers, when used as a filament, produced 0:12:32.360 --> 0:12:34.640 better light than the carbon paper version he had been 0:12:34.679 --> 0:12:38.080 relying on and his process for making carbon fiber would 0:12:38.160 --> 0:12:42.160 become a standard. There are chemists and labs today who 0:12:42.240 --> 0:12:45.000 essentially use the exact same approach, though things get way 0:12:45.040 --> 0:12:49.360 more complicated when you're talking about mass engineering. For you, 0:12:49.640 --> 0:12:53.719 big industrial uses of carbon fiber. Now we're going to 0:12:53.760 --> 0:12:55.480 take a quick break. When we come back, we'll talk 0:12:55.559 --> 0:12:59.480 more about what makes carbon fiber special, but first let's 0:12:59.520 --> 0:13:12.960 hear from our sponsors. Okay. As smart as smarty pants 0:13:13.120 --> 0:13:16.840 Swan was, he wasn't able to see the potential mechanical 0:13:16.920 --> 0:13:19.839 applications of carbon fiber. He was just using it as 0:13:19.880 --> 0:13:23.280 an incandescent bulb filament. But he had no way to 0:13:23.320 --> 0:13:26.240 know that his material, if woven properly and combined with 0:13:26.400 --> 0:13:30.320 other stuff, could be strong, lightweight, and perfect for futuristic 0:13:30.360 --> 0:13:35.160 applications like the aerospace industry. Silly Swan not to anticipate 0:13:35.200 --> 0:13:38.480 all those uses back in the mid nineteenth century. Now. 0:13:38.520 --> 0:13:41.479 In fact, carbon fiber would kind of go into hibernation 0:13:41.600 --> 0:13:44.760 for many decades because there just weren't any practical uses 0:13:44.800 --> 0:13:47.920 for it or any real way to produce it at scale. 0:13:48.520 --> 0:13:51.319 It re emerged in nineteen fifty eight when a physicist 0:13:51.400 --> 0:13:55.080 named Roger Bacon produced carbon fiber and discovered that if 0:13:55.120 --> 0:13:59.200 constructed properly, it would be a really stiff, really strong, 0:13:59.320 --> 0:14:03.640 and extremely lightweight material. But it was super expensive to 0:14:03.679 --> 0:14:06.760 produce due to the time and effort involved, and the 0:14:06.880 --> 0:14:09.839 small amount of output you would get meant that there 0:14:09.880 --> 0:14:11.840 wasn't much you could do with it, so there was 0:14:11.880 --> 0:14:14.920 no commercial use for it just yet. But he was 0:14:14.960 --> 0:14:19.280 showing that this material had promise and that people would 0:14:20.080 --> 0:14:24.920 likewise start to pour money into improving manufacturing processes to 0:14:24.960 --> 0:14:29.800 make it practical. The evolution of those processes happened mainly 0:14:29.880 --> 0:14:32.960 in the nineteen seventies. Scientists in different parts of the 0:14:32.960 --> 0:14:36.200 world found new ways to produce carbon fibers. Some of 0:14:36.200 --> 0:14:39.120 those would be suitable for high heat applications, such as 0:14:39.160 --> 0:14:42.680 in the aerospace industry, where you might need to radiate 0:14:42.760 --> 0:14:45.920 heat outward from an engine before you get to a 0:14:45.920 --> 0:14:49.800 point where that's no longer your concern. Others would be 0:14:49.880 --> 0:14:53.760 suitable for more terrestrial uses. The eighties and nineties proved 0:14:53.760 --> 0:14:56.840 to be a boom era for carbon fiber research and development, 0:14:56.920 --> 0:14:59.760 as engineers recognized the material as being a good candidate 0:14:59.800 --> 0:15:03.960 for various applications, particularly in the space industry. Where there 0:15:04.000 --> 0:15:07.320 is a real need to create materials that are very strong, 0:15:07.760 --> 0:15:10.200 but you also want to cut way back on weight 0:15:10.600 --> 0:15:12.880 as much as you can in order to reduce the 0:15:12.880 --> 0:15:15.560 amount of energy you need to launch the stuff off 0:15:15.600 --> 0:15:18.680 this rock in the first place. So carbon fiber would 0:15:18.680 --> 0:15:23.760 become a really strong candidate for lots of space based applications. Now, 0:15:23.760 --> 0:15:27.520 as I mentioned earlier, carbon fiber has some really cool properties. 0:15:27.560 --> 0:15:31.920 It is really strong and really light. In fact, it's 0:15:31.960 --> 0:15:35.600 five to ten times stronger than steel, depending upon which 0:15:35.680 --> 0:15:39.720 source you're reading and the method of production for carbon fibers, 0:15:39.760 --> 0:15:42.680 and the specific type of steel you're talking about, and 0:15:43.120 --> 0:15:46.600 what you're actually looking at. So saying it's stronger than 0:15:46.640 --> 0:15:49.880 steel has really a simple answer to a complex situation, 0:15:50.040 --> 0:15:51.640 and it does mean that we need to spend a 0:15:51.640 --> 0:15:54.680 little bit more time to talk about material strength and 0:15:54.720 --> 0:15:59.520 what that actually means. So essentially, we quantify a material 0:15:59.600 --> 0:16:03.600 strength by examining how much stress or strain it can 0:16:03.640 --> 0:16:08.440 withstand before the structure we're looking at deforms to a 0:16:08.520 --> 0:16:11.920 point that when we remove the stress, it will not 0:16:12.120 --> 0:16:14.720 go back to its original shape. So, in other words, 0:16:14.720 --> 0:16:18.320 if you were to bend a bar and then you 0:16:18.400 --> 0:16:21.480 stop applying force, to the bar and the bar stays bent, 0:16:21.960 --> 0:16:25.240 you have exceeded the material strength of that bar. And 0:16:25.560 --> 0:16:29.720 if it pops back into its regular bar shape, then 0:16:29.760 --> 0:16:33.480 you did not exceed the material strength of that bar. 0:16:34.280 --> 0:16:36.720 There are different kinds of stresses that you can apply 0:16:36.960 --> 0:16:39.640 to materials, So when we say something is strong, we 0:16:39.680 --> 0:16:43.760 actually have to think about in what context. So again, 0:16:43.840 --> 0:16:46.200 let's talk about it having a short pipe. Now it's 0:16:46.200 --> 0:16:48.640 made out of whatever, it doesn't matter. We're just talking 0:16:48.640 --> 0:16:51.520 about the types of stresses you could put on this pipe. 0:16:51.920 --> 0:16:55.120 So let's say that you were to grip either end 0:16:55.160 --> 0:16:58.760 of that pipe and you were to pull in opposite directions, 0:16:59.080 --> 0:17:02.760 trying to allow lung gate the pipe. You're putting tension 0:17:02.920 --> 0:17:07.920 on it. This is the test for tensile strength of 0:17:08.200 --> 0:17:10.760 the pipe. How well does it hold up to stresses 0:17:10.800 --> 0:17:14.680 that attempt to elongate the material. And once you reach 0:17:15.280 --> 0:17:19.159 the point where you have exceeded that material strength, that 0:17:19.320 --> 0:17:23.480 tensile strength of that material, does it rip apart? Does 0:17:23.520 --> 0:17:27.840 it shatter? What happens? Now? What if instead of pulling 0:17:27.880 --> 0:17:31.439 on either end, you were pushing inward on either end 0:17:31.480 --> 0:17:35.560 of the pipe. You're trying to compress the pipe, You're 0:17:35.600 --> 0:17:38.879 squeezing the material. In other words, typically most materials have 0:17:38.960 --> 0:17:43.600 a high compressive strength compared to tensile strength, like a 0:17:43.680 --> 0:17:47.399 higher one. There are some elements at play here that 0:17:47.480 --> 0:17:51.720 can lead to other complications, Like, yes, it may be 0:17:51.880 --> 0:17:57.359 that it can withstand compression and it doesn't really compress 0:17:57.440 --> 0:18:00.520 beyond a certain point, but it might buckle, right, So 0:18:00.560 --> 0:18:02.720 there are other elements you have to look at when 0:18:02.760 --> 0:18:07.040 you're testing compressive strength. Then you've got sheer strength. Now, 0:18:07.080 --> 0:18:10.680 not sheer as an sh ee r strength. I'm talking 0:18:10.680 --> 0:18:14.920 about sh ea r strength like a pair of shears, 0:18:15.320 --> 0:18:19.400 because scissors effectively put this kind of stress on a material. 0:18:19.920 --> 0:18:23.439 So a shear stress is one in which the stress 0:18:23.480 --> 0:18:26.480 on either end of the material is parallel to each other, 0:18:27.160 --> 0:18:29.560 but they're in opposite direction. So if you think of scissors, 0:18:29.720 --> 0:18:32.840 like when the blades of scissors are coming together, one 0:18:32.880 --> 0:18:35.959 blade moving down, the other blade moving up, it is 0:18:36.240 --> 0:18:39.240 putting that kind of pressure on the material that you're cutting. Right, 0:18:39.800 --> 0:18:42.160 the one blade is moving up, one blade is moving down, 0:18:42.200 --> 0:18:44.320 so they are parallel to each other, but they're moving 0:18:44.359 --> 0:18:48.480 in opposite directions. And if you apply that kind of 0:18:48.560 --> 0:18:51.400 stress to a material, you can find out how resistant 0:18:51.480 --> 0:18:55.960 it is to shear stresses. So this is also called 0:18:56.320 --> 0:19:03.680 torsional loading. Right, You're at a torsional load to the material. Now, 0:19:03.720 --> 0:19:08.520 comparing materials against each other isn't always as simple as 0:19:08.520 --> 0:19:12.160 saying one is stronger than the other. One material might 0:19:12.240 --> 0:19:16.440 have greater tensile strength, meaning it could withstand elongation better 0:19:16.480 --> 0:19:19.360 than another material could in the same sort of situation. 0:19:20.160 --> 0:19:22.960 But maybe that first material can't hold up to the 0:19:23.000 --> 0:19:28.320 same sheer stresses that material two can withstand. You know, 0:19:28.400 --> 0:19:33.360 like some Facebook relationship status is it's complicated? Just does 0:19:33.400 --> 0:19:36.560 Facebook actually still have its complicated as a relationship status? 0:19:36.760 --> 0:19:39.520 Is anyone still on Facebook? Can I get a check 0:19:39.560 --> 0:19:43.159 on that? Anyway? Let's get back to carbon fiber. I 0:19:43.200 --> 0:19:45.879 think one way we can look at this is to 0:19:45.920 --> 0:19:51.159 think of strength in comparison to some other component and 0:19:51.200 --> 0:19:53.960 then compare two different materials. So in this case, we'll 0:19:54.000 --> 0:19:59.160 say strength to weight ratio. How strong is something compared 0:19:59.160 --> 0:20:01.920 to how much which it weighs. If we do that, 0:20:02.160 --> 0:20:05.200 if we look at it as strength to weight, carbon 0:20:05.240 --> 0:20:09.520 fiber is way stronger than steel. If you have a 0:20:10.240 --> 0:20:14.239 pound of carbon fiber and a pound of steel and 0:20:14.400 --> 0:20:18.520 they both have been made into some sort of you know, structure, 0:20:19.080 --> 0:20:22.000 the carbon fiber is going to be technically stronger than 0:20:22.040 --> 0:20:24.480 the steel is, and that's because steel is a really 0:20:24.600 --> 0:20:29.440 super dense material. So depending upon the application, a lightweight 0:20:29.520 --> 0:20:33.160 carbon fiber structure might be the way to go. For example, 0:20:33.320 --> 0:20:36.280 if you wanted to create a resilient helmet for football 0:20:36.280 --> 0:20:40.920 players I'm talking about American football here, well you would 0:20:41.000 --> 0:20:43.840 probably want to go with carbon fiber, not with steel, 0:20:43.960 --> 0:20:46.720 because I'm pretty sure no football player wants to wear 0:20:46.720 --> 0:20:49.199 a big steel helmet out on the field. But a 0:20:49.280 --> 0:20:54.240 lightweight helmet made with carbon fiber, that's a different story. However, 0:20:54.280 --> 0:20:58.359 if we were to instead look at strength compared to volume, 0:20:59.000 --> 0:21:02.680 the story is different. I watched a video from Crazy 0:21:02.800 --> 0:21:08.520 Hydraulic Press that compared stuff like acrylic fiberglass, aluminum, or 0:21:08.600 --> 0:21:14.240 aluminium if you prefer brass, titanium, steel, and carbon fiber 0:21:14.840 --> 0:21:20.080 to a hydraulic press test. The video has all of 0:21:20.119 --> 0:21:23.760 these materials made in the same simple shape a rectangular rod, 0:21:24.280 --> 0:21:26.200 so you know, it's like a rod, but it's squared off, 0:21:26.240 --> 0:21:29.640 it's not a circular rod, and it's the exact same 0:21:29.800 --> 0:21:34.520 dimensions for every single material, same length, same with you know, 0:21:34.640 --> 0:21:38.639 So that way you've got different substances, but they all 0:21:38.720 --> 0:21:42.000 are making rods of the exact same size from each substance. 0:21:42.600 --> 0:21:45.800 And that means that when you put the rods next 0:21:45.840 --> 0:21:48.040 to each other, the carbon fiber rod is going to 0:21:48.080 --> 0:21:51.959 weigh a lot less than the steel rod will, right, 0:21:52.040 --> 0:21:55.960 because steel is way more dense, it's heavier, it's gonna 0:21:55.960 --> 0:22:00.480 have more mass, even though the physical dimension of the 0:22:00.520 --> 0:22:04.080 two rods will otherwise be identical. Right, And if you 0:22:04.119 --> 0:22:07.479 put these two different rods to the test, the steel 0:22:07.480 --> 0:22:10.879 one's likely to hold up better because by volume, steel 0:22:10.960 --> 0:22:14.040 is the stronger material. If you look at weight, carbon 0:22:14.119 --> 0:22:17.919 fibers the stronger material. Like I said, it's complicated. And 0:22:18.000 --> 0:22:20.200 for the record, in the video I watched, the carbon 0:22:20.240 --> 0:22:23.280 fiber rod had a mass of fifteen point two grams 0:22:23.680 --> 0:22:26.120 and the steel rod had a mass of seventy six 0:22:26.160 --> 0:22:29.160 point eight grams. If we were to convert that to weight, 0:22:29.240 --> 0:22:31.199 and let's say we just go with pounds just to 0:22:31.240 --> 0:22:34.399 make it silly, then the carbon fiber weigh just point 0:22:34.600 --> 0:22:38.719 zero three pounds. The steel rod weighed point one seven, 0:22:38.960 --> 0:22:43.679 so way way more than the carbon fiber rod. And 0:22:43.680 --> 0:22:48.800 in the video they set the rods lengthwise across two prongs, 0:22:49.359 --> 0:22:52.359 metal prongs, and they use a hydraulic press to apply 0:22:52.520 --> 0:22:56.199 stress down across the length of the rod, like to 0:22:56.280 --> 0:22:58.320 push down right in the middle. So it's sort of 0:22:58.400 --> 0:23:00.000 like if you were to take a branch and try 0:23:00.200 --> 0:23:03.000 to break it in half across your leg. The carbon 0:23:03.040 --> 0:23:05.639 fiber rod broke when the press hit seven hundred and 0:23:05.640 --> 0:23:10.560 forty kilograms of weight at that point of the rod, 0:23:11.000 --> 0:23:15.199 and the steel held out till three thousand, eight hundred 0:23:15.560 --> 0:23:19.840 seventy kilograms. So again, carbon fiber seven hundred and forty, 0:23:20.200 --> 0:23:24.000 steel threey, eight hundred and seventy. But the story would 0:23:24.000 --> 0:23:27.880 be totally different if instead of volume, we were going 0:23:27.920 --> 0:23:31.320 by weight. If you had fifteen point two grams of 0:23:31.400 --> 0:23:34.800 carbon fiber and fifteen point two grams of steel, you 0:23:34.800 --> 0:23:38.040 would see that the carbon fiber would hold up way 0:23:38.119 --> 0:23:41.240 better because that would be a very small steel rod, 0:23:42.240 --> 0:23:46.439 very thin, and it would deform much faster than the 0:23:46.480 --> 0:23:52.000 carbon fiber would. And I'm going to talk more about 0:23:52.200 --> 0:23:55.040 carbon fiber, but we do need to take another quick 0:23:55.080 --> 0:23:57.760 break to thank our sponsors. We'll be right back to 0:23:57.840 --> 0:24:02.200 talk a bit more about what carbon fiber is used 0:24:02.200 --> 0:24:04.880 for and how it's used. Because it's not as simple 0:24:05.520 --> 0:24:08.879 as just making a frame out of carbon fiber. But 0:24:08.920 --> 0:24:20.280 we'll talk about that in just a moment. Okay, before 0:24:20.320 --> 0:24:25.479 the break, I talked about how carbon fiber is not 0:24:25.680 --> 0:24:28.600 just used as pure carbon fiber and stuff. In fact, 0:24:29.480 --> 0:24:33.600 we're usually talking about carbon fiber that is bonded to 0:24:33.840 --> 0:24:37.119 some other material, and carbon fiber access kind of like 0:24:37.160 --> 0:24:40.239 a reinforcing layer. So I like to think of it 0:24:40.280 --> 0:24:45.119 as similar to iron rebar that's inside a concrete structure, 0:24:45.680 --> 0:24:49.760 because the carbon fiber is providing strength and resilience, but 0:24:49.800 --> 0:24:53.200 it doesn't make up the totality of say the football helmet, 0:24:53.240 --> 0:24:56.400 for example, you have a binding agent in there. Typically 0:24:56.480 --> 0:24:59.720 you're using something like plastic and you're reinforcing it with 0:24:59.800 --> 0:25:03.840 carb fiber. So, to put it in another way, steel is 0:25:04.000 --> 0:25:09.600 really hard stuff. It's also really heavy, and it's challenging 0:25:09.640 --> 0:25:13.159 to mold steel into complicated shapes. We can do simple 0:25:13.200 --> 0:25:15.879 shapes pretty easily, but if you want to do something 0:25:15.960 --> 0:25:22.159 like a really a complex curve, maybe multiple curves in 0:25:22.240 --> 0:25:26.520 a single panel, it's hard to get steel to take 0:25:26.560 --> 0:25:31.320 that shape and not have it be an exorbitantly expensive process. 0:25:31.760 --> 0:25:35.840