Randomly stacked open-cylindrical shells as a functional mechanical device

TL;DR

This paper investigates randomly stacked cylindrical shells as a disordered mechanical metamaterial that can absorb and store energy through large deformations, with performance governed by friction and geometry, offering a versatile approach to mechanical design.

Contribution

It introduces a novel disordered metamaterial using randomly stacked shells, demonstrating robust energy absorption and storage capabilities through experiments and simulations.

Findings

Stacks can absorb energy via large deformation and shell relocation.

Mechanical performance is robust despite random shell orientation.

Friction and geometry control the system's mechanical response.

Abstract

Structures with artificial mechanical properties, often called mechanical metamaterials, exhibit divergent yet tunable performance. Various types of mechanical metamaterials have been proposed, which harness light or magnetic interactions, structural instabilities in slender or hollow structures, and contact friction. However, most of the designs are precisely engineered without any imperfections, in order to perform as programmed. Here, we study the mechanical performance of randomly stacked cylindrical-shells, which act as a disordered mechanical metamaterial. Combining experiments and simulations, we demonstrate that the stacked shells can absorb and store mechanical energy upon compression by exploiting large deformation and relocation of shells, snap-fits, and friction. Although shells are oriented randomly, the system exhibits robust mechanical performance controlled by friction and geometry. Our results demonstrate that the rearrangement of flexible components could yield versatile but predictive mechanical responses.