If you were to strip away the walls, floors, and insulation, you’d see that most buildings are constructed on a frame of beams. Most beams are made from steel, and while strong, they’re fairly one-size-fits-all. A new study published in the journal Physical Review Letters found that fractal patterns could be used to create 3d printed beams that are lighter and up to 10,000 times stronger than typical steel beams! This combination of material science and 3D printing technology could make it possible to customize beams for a specific load and purpose, reducing waste and cost.
The process, developed by Yong Mao of the University of Nottingham, UK and colleagues is multi-faceted and requires several iterations of development, but ultimately it mimics structures seen in nature for eons. A fractal is a pattern or structure that is self-similar on all length scales, which basically means an object is made up of thousands of tiny versions of itself. Fractal patterns are seen in nature at all scales – everything from a single fern leaf that resembles the entire plant, to clouds, snowflakes, blood vessels and cauliflowers demonstrate this design.
Yong developed a theoretical framework for building structures where the optimal hierarchical order of the structure depends on the load it needs to withstand. Using this technique, the team constructed such a structure – a simple hollow frame – from a polymeric resin, using a “rapid prototyping technique” – which is an advanced form of 3D printing. Then they evaluated how well it bore the load they wanted to place on it (not very well). Then they analyzed the failure points using sophisticated software and designed a fractal structure that will address the weak points. This process was repeated several times. Each tweak produced a new “generation” of the beam. Third generation beams, about as far as we can hope to go with current tech, are 10,000 times stronger than steel, reports Gizmodo.
A drawback of this kind of fabrication is that imperfections in the material could cause serious problems. “Even a small imperfection at a local scale could have a large impact as there is no extra material that could take the added stress and maybe that is why this kind of fabrication has not been practical to date,” Yong explained to PhysicsWorld. He says that the team is also studying its models make them resistant to such errors. But he is convinced that commercial techniques will improve over the coming year, providing the necessary precision tools. Mao also feels that the recently commercialized technique of 3D printing could really benefit the fabrication of these structures. “We could just upload our different designs to a program and people could download and print off the structures at home,” he continued.