In our traditional cognition, a specific substance often has only a certain attribute. Because of this, this material can only be used in one or several fields, and it does not have wider universality.

So, is it possible to develop a new material with multiple properties, which can be used in many fields? Scientists all over the world are exploring how to solve this problem.

Recently, researchers from the Massachusetts Institute of Technology (MIT) and the United States Army Research Laboratory have successfully developed a new material with many characteristics, which is not only low in cost, easy to manufacture, but also very fast in assembly. They even cooperated with Toyota to produce a practical super mileage racing car.

The related paper named "Discrete Assembled Mechanical Metamaterials" was published online in the scientific journal Science Progress on June 5438+065438+1October 18, 2008.

Researchers say that, just like bionics and integrated design, this new material will be a very powerful new tool, which can help us "get twice the result with half the effort". Robots can produce large and complex objects, such as cars, robots and wind turbine blades, by assembling subunits composed of these materials.

This research was also supported by the National Aeronautics and Space Administration (NASA).

In order to verify the potential of these materials to build large objects in the form of Lego in the real world, the researchers cooperated with Toyota engineers to produce a functional super-mileage racing car, which was exhibited at an international robotics conference earlier this year.

Benjamin Jenett, one of the authors of the paper, said that they can assemble a lightweight and high-performance structure in just one month, while it takes a year to build a similar structure using traditional glass fiber construction methods.

During the exhibition, the road surface became smooth because of the rain, which led to the car finally hitting an obstacle. However, to everyone's surprise, despite the deformation of the internal structure of the car's lattice, it "bounced" and absorbed the shock caused by the impact, with almost no damage.

Janet said that if it is a traditional car made of metal, the body may have been seriously sunken, while if it is a car made of composite materials, it may break. This racing car truly shows that these tiny parts can really be used to make functional devices of human size.

Because these materials are basically the same in size and composition, they can be combined in any necessary way to provide different functions for larger equipment.

In this regard, Dr Neil Gershenfeld, one of the authors of the paper, said: "We can make a robot with these materials, which bends in one direction, but is hard in the other direction and can only move in a specific way. Therefore, compared with our early work, the biggest change is that it can combine the characteristics of various mechanical materials. Before that, people always studied the application of a certain nature. "

So, what kind of materials can give cars this ability?

Researchers call this new type of material "mechanical metamaterial", which is named "metamaterial" because its macroscopic characteristics are different from those of its constituent materials.

In this work, they created four different types of micro-subunits, also called voxels. They are rigid metamaterials, compliant metamaterials, tension metamaterials and chiral metamaterials.

Voxel is assembled by injection-molded polymer flat frame, which can be combined into three-dimensional shapes from small to large and then connected to larger functional structures. Most of them will present an open space and provide a very light but hard assembly frame. Among them, each type of voxel shows special properties that natural materials do not have.

Rigid voxels are characterized by high strength and light weight.

The Poisson's ratio of "compliant" voxels is zero, which is somewhat similar to the extended characteristics. But in this case, when the material is compressed, the side shape of the material will not change. Few known materials can show this performance. Now, researchers can produce this material through new methods.

The "growth" voxel has unusual characteristics. When it is compressed, the cubic substance actually expands inward instead of sideways. This is the first time that this material has been produced and displayed by traditional and cheap manufacturing methods.

Chiral voxels are characterized by twisting motion in response to axial compression or stretching. Again, this is an unusual attribute.

At the same time, researchers can combine them to make devices that can respond to environmental stimuli in a predictable way. Such as airplane wings or turbine blades, which respond to changes in air pressure or wind speed by changing the overall shape.

In this regard, Gershenfeld said, "Every property we have shown has been used in independent fields before, and scientists have only conducted research based on one of them. This is the first time that so many attributes have been integrated into one system. "

Janet said that these materials are not only cheap, easy to manufacture, fast to assemble, but also compatible with each other. Therefore, they can have many different types of peculiar properties at the same time, and play a very good role in the same scalable and cheap system.

The key to making this material so special is that when it is stressed, the structure composed of this voxel will change in exactly the same way as the subunit itself. This study proves that when researchers assemble parts together, all the connected places are "perfectly" coupled together and become a continuous whole.

Jenett believes that the early application of this technology may be used to manufacture blades of wind turbines. With the structure of wind turbine blades becoming larger and larger, it has become a serious transportation problem to transport the blades to the workplace. If the blades are assembled by thousands of tiny subunits at the workplace, the transportation problem can be eliminated.

At the same time, due to the large blade size and lack of recyclability, the disposal of abandoned turbine blades has also become a serious problem. Blades made of tiny voxels can be disassembled on site and then reused to make other things.

In addition, the working efficiency of the blades themselves will become higher, because they have various mechanical properties and can dynamically and conveniently cope with the change of wind strength.

This new material can also empower robots. Today's robots are either rigid robots or flexible robots. If robots are endowed with various mechanical properties, perhaps robots will gain more unexpected abilities.

"Now, we have this low-cost and scalable system. We can design any object we want, such as quadrupeds, swimming robots and flying robots. The flexibility required by these objects is also one of the main advantages of the system. " Jnett added.

For this research, Professor Amauri lovins of Stanford University said, "This technology can create a low-cost, durable and very lightweight aviation flight surface, just like the wings of birds, which can change shape conveniently and continuously; In addition, it may make the empty mass of the car closer to its payload, because their anti-collision structure is mainly air; It can even make the compressive strength of the spherical shell reach an unprecedented level, and make the net load of the helium-free vacuum balloon floating in the air reach dozens of times that of a large jet plane. "

I believe that the appearance of this new material can bring infinite possibilities to future scientific research and life.

References:

https://advances.sciencemag.org/content/6/47/eabc9943

https://advances . science mag . org/content/Suppl/2020/ 1 1/ 16/6.47 . eabc 9943 . DC 1

https://news . MIT . edu/2020/versatile-building-blocks- 1 1 18