Collaborative research by Tomohiro Mimura, Prof. Katsuhiko Sato of the University of Toyama, and colleagues has been published in the Journal of the Physical Society of Japan (JPSJ). The paper was also selected as one of the Papers of Editors’ Choice.
This study establishes the geometric conditions under which rod-like elements with periodic surface corrugations can form helicoidal stacks while maintaining concavity-to-concavity contact between adjacent layers. The authors theoretically showed that the intralayer phase shift is restricted to either zero or half the axial period and that the stackable pitch angles form discrete series determined by integers. These results were verified using collision detection and rigid-body simulations, which also showed that structures with smaller pitch angles are mechanically less stable. The findings advance our understanding of the formation principles underlying helicoidal laminates found widely in natural and engineered materials, including Bouligand structures and fiber-reinforced composites.
Discrete Pitch-Angle Conditions for Helicoidal Stacking of Periodically Corrugated Rods