Everything has its two sides and its advantages and disadvantages, and 3D printing is no exception. A very common disadvantage of 3D printing is that the strength of the parts produced by it is not as strong as those produced by traditional manufacturing. However, with the continuous progress of 3D printing materials and technology, 3D printing parts also show their unique strength and durability, which are equal to and even surpass traditional manufacturing. Now researchers at the University of Wisconsin Madison in Madison, the capital of Wisconsin, have developed 3D printing materials that are much stronger than other materials used in architecture.
Professor Roderic lakes of Engineering Physics and graduate student Zachariah rueger 3D printed a material whose behavior is consistent with Cosserat’s elasticity theory, also known as micropolar elasticity. When analyzing its physical properties under high pressure, the theoretical factors in the material substructure. Using this theory, lakes and rueger designed a polymer lattice with a bending stiffness 30 times higher than that predicted by the classical elastic theory. The lattice consists of polymer bands arranged in a repeated cross design, which can increase strength and durability.
“If you have a substructure in your material, such as some foam, lattice and fiber reinforced materials, it has a greater degree of freedom than classical elastic theory can handle,” says lakes. “So we are studying the free behavior of materials, not the way expected by standard theory.”
The freedom of materials opens the “door” to creating new materials that are not affected by stress concentration, that is, they are stronger than any other material. Practical applications may include making aircraft wings more crack resistant. If cracks appear on the wing of an aircraft, the stress is concentrated around the cracks, making the wing weaker.
“You need a certain amount of pressure to break something, but if it has a crack, you can break it with less pressure,” lakes said.
However, Cosserat theory produces materials with different pressure distribution, which makes it more difficult. This behavior can be seen in bones and some types of foam. However, when making foam seat cushions, engineers do not have much control over the underlying structure of foam, so their ability to adjust the Cosserat effect is limited.
However, lakes and rueger can adjust the Cosserat effect in their 3D printing materials to make it very powerful.
“We have developed a material, and we have very detailed control over the fine structure of the lattice, which enables us to achieve very powerful effects when bending and twisting materials,” lakes said.
Most buildings are designed based on classical elastic theory, such as buildings, aircraft, bridges and electronic equipment – but this new design based on Cosserat theory can produce outstanding materials. Through 3D printing materials, engineers can better control their performance and structure, which may lead to a new way of building, or at least design some components, such as the aforementioned aircraft wing.