A carbon sheet no thicker than a human's hair can withstand the impact from tiny bullets traveling at twice the speed sound.Researchers are looking for materials that can withstand the impact of space debris and rogue shrapnel. Carlos Portela from the Massachusetts Institute of Technology, Julia Greer from the California Institute of Technology, Pasadena, and their collaborators designed a lattice that looks like a 3D honeycomb. Each cell has 14 sides. The lattice was constructed using 3D printing and heated until it contained only pure carbon.Researchers fired small spheres that resembled sand particles at the material. They were only a few micrometres wide. The spheres bounced off of the lattice at lower speeds. They were able to gouge out neat craters, crush the lattice beneath, and remain in the pits rather than piercing it at higher speeds.Researchers could predict the formation of craters in their materials by adjusting a model that explains meteorite cratering. Their model could be used to inform other lightweight blast-proof designs.
