People get tired, and metal is no exception. But when metal gets tired, it just breaks. What's going on here?
I think we all did this when we were kids, bending wire over and over again. In the same place, keep bending, and eventually the piece of wire will break. Have you ever wondered how this works? And that's actually what this episode is about -- metal fatigue. Yes, metals also tire, and when subjected to repeated cycles of force, they break directly in a place where the stress is concentrated.
If we want to understand metal fatigue in detail, we need to understand a word - cyclic stress. As the name suggests, it's a constant cycle of stress. Just like when we bend a wire, we create a cyclic stress inside the wire. So how do we understand this cyclic stress? There is another name for cyclic stress which is called alternating stress or repeated stress 39bet-kết quả bóng đá-kết quả xổ số miền bắc-kèo bóng đá -soi cầu bóng đá-đặt cược. Cycle, altercation, and repetition all have one thing in common, and that is periodic change. That is to say, the stress we cause to it is periodic and regular. Under the action of stress one after another, the metal is tired, and the damage to the metal itself is caused. At this time, the failure is called fatigue failure. We're always talking about two, three, four. The same applies to metals. We can simply understand that because we apply stress over and over again, the metal gets restless and impatient, so it breaks down.
For example, when we give a wire a hammer, the force of the hammer is the force exerted by the outside world on the wire. Under the force of the hammer, the wire is smashed flat by us. In order to make the wire return to its previous shape, the internal forces interacting with each other in the wire, that is, the stress.
Now you guys have a pretty good idea of what cyclic stress is, right? Under the action of repeated cyclic stress, although the metal itself does not break at the beginning, small cracks in its body are constantly accumulating. When the accumulation to the end, the fracture has been particularly serious, at this time there will be a complete fracture, and this situation is unavoidable, which is metal fatigue.
And of course, the only way to do that is if we apply metal fatigue to parts of the metal. Or take the bending of the wire as an example, constantly bending a part of the wire, the wire will be broken, which is an important feature of metal fatigue, that is, the location of the locality, which we can understand as click by click. But when you think about it, metal fatigue is an interesting physical property. Every time we stress the metal beyond its stress limit, it breaks after many sets of stress. So what does that tell us? Quantitative change produces qualitative change. Every small effort seems insignificant, but in the end, it will lead to revolutionary change.
Here friends may ask, since metal fatigue is unavoidable. How can we reduce the damage caused by metal fatigue? Here we have another element, the rare earth elements. Despite their name, they are not just one element, but a collection of 17 elements. Rare earth elements can be said to be the lubricant of industrial production. With the existence of rare earth elements, our industrial equipment and products will take on a new look. And if we add rare earth elements to the metal, the metal will be more resistant to fatigue. So the question is, how much do we add? The rare earth is already very precious. If you add too much, won't it lose money? We don't need to add much, we just need to add a few ten-thousandths, and that's enough.
And any physical characteristics are often a double-edged sword. There are disadvantages, but also advantages. We through the characteristics of metal fatigue, but also developed a stress breaker. This device is also well understood, which uses metal fatigue to make metal break.