Biomimetic architected materials with improved dynamic performance

Abstract

In recent decades, material performances improved by the discovery of new bulk materials have slowed down. By contrast, novel and unprecedented material properties have been demonstrated under the concept of “architected materials”, where the material properties are dominated by material microstructure instead of constituents. Knowing that mother nature is “a master of material architecture” through millions of years evolution – nearly all natural materials have elegantly fine and organized structures showing excellent impact resistance and damage tolerance. In this study, we design material architectures mimicking biomaterials and 3D print architected beams with dynamic performance far beyond their bulk constituents. By performing dynamic three-point bending tests and digital image correlation analysis, we characterize five types of bioinspired microstructures and propose the criteria of architecture selection adopting the concept of material indices. The reason why certain microstructures are preferred by certain organisms and how to optimally select material architectures for specific engineering applications are illustrated. Furthermore, microstructure integration approaches that work on multiple length scales (hierarchical designs) and on one specific length scale (hybrid designs) are investigated. Applying these approaches, we have designed architected beams that are flexible and strong, strong and tough, dissipative and stiff, and flexible and responsive, which are typically exclusive in bulk materials. Additionally, material architectures give extra control of fracture patterns, improving the critical impact energy by over 6 times. This work provides insights to the structure–property relationships and will facilitate the development of architected materials with tailored performances of flexibility, strength, toughness, energy dissipation, and fast response.