Vibration-driven fabrication of dense architectured panels

Aram Bahmani [McGill University] Hannard, Florent [UCL] J. William Pro [McGill University] Francois Barthelat [University of Colorado]

Self-assembly at the macro-scale is a promising pathway for fabrication, but the assembly process and mechanisms are still poorly understood. We examine the vibration-induced assembly of hard cubic grains as a potential route for the rapid fabrication of architectured materials and structures. We performed assembly experiments with various combinations of vibration amplitudes and frequencies to map the different states of the system. The results show that the acceleration normalized by gravity cannot fully capture the phase transitions or the mechanisms governing cubes packing and that amplitude and frequency must be considered independently. We used discrete element modeling to duplicate experiments and then single-grain models to find the effective mechanisms involved in the packing and phase transition of cubes. Both cube rotation and bouncing govern packing, while bouncing has an additional role in the phase transition. These findings provide guidelines for the assembly of complex materials, for example, topologically interlocked materials.