Vibration-induced assembly of topologically interlocked materials

Abstract

Dense architectured, granular, and other material systems based on the assembly of discrete building blocks provide mechanical responses not ordinarily achieved in monolithic materials. The performances of these material systems can be tuned and expanded by simply changing the building block geometry, their packing arrangement, and/or their jamming states. Applications for these material systems have however remained limited, in part because of fabrication challenges and scalability. We explored the vibration-driven assembly method to form periodic arrangements of convex polyhedral building blocks into large-piece free-standing topologically interlocked panels. We used a combination of experiments and discrete elements modeling (DEM) to explore how vibration can be manipulated to steer polyhedral building blocks into one of three possible states: static, assembly, and fluttering and study the governing physics and mechanics underlying these states. The results specified the role of the normalized relative acceleration of mechanical agitation, bouncing, and rotation mechanisms on both phase transitions and crystallization and/or interlocking. The geometry-dependency, re-fragmentation, re-crystallization, and re-configurability of athermal out-of-equilibrium material systems can be understood and optimized based on our findings and provided guidelines in this study.