Digital cellular solids : reconfigurable composite materials

Abstract

Digital materials are comprised of a small number of types of discrete physical building blocks, which assemble to form constructions that meet the versatility and scalability of digital computation and communication systems. This work seeks to demonstrate the applicability of a digital material approach in designing new cellular materials and methods for assembly of structures with static reconfigurability. The science of cellular solids has enabled the widespread use of lightweight materials to meet important engineering needs, such as passive energy absorption, but they are not in widespread use for structural applications, perhaps due to a large gap between the strength and stiffness to weight ratios of popular classical solids, and the performance of known lightweight cellular materials that are produced from the same constituent material. The engineering of fiber reinforced composite materials has enabled structures with large reductions in weight for given strength and stiffness targets, but at very high design and processing costs, and many challenges producing mechanical interfaces (joints). Digital materials promise scalable methods of producing functional things with reconfigurable sets of discrete and compatible parts, but the presence of many reversible connections raises questions about the performance of the end result. Digital Cellular Solids are cellular solids that exhibit improvements in relative stiffness and strength compared to relative density, over current practices for producing lightweight materials. This is accomplished by assembling lattice geometries that perform better than any that we know how to make with traditional methods. When implemented with fiber composites, the result is not only stiffer and stronger than any previously known ultra-light material, but it presents a new scalable and flexible workflow for applying fiber composites to engineering problems.