A Snakeskin-Inspired, Soft-Hinge Kirigami Metamaterial for Self-Adaptive Conformal Electronic Armor

A majority of soft-body creatures evolve armor or shells to protect themselves. Similar protection demand is for flexible electronics working in complex environments. Existing works mainly focus on improving the sensing capabilities such as electronic skin (E-skin). Inspired by snakeskin, a novel electronic armor (E-armor) is proposed, which not only possesses mechanical flexibility and electronic functions similar to E-skin, but is also able to protect itself and the underlying soft body from external physical damage. The geometry of the kirigami mechanical metamaterial (Kiri-MM) ensures auxetic stretchability and meanwhile large areal coverage for sufficient protection. Moreover, to suppress the inherent but undesired out-of-plane buckling of conventional Kiri-MMs for conformal applications, soft hinges are used to form a distinct soft (hinges)-rigid (tiles) configuration. Analytical, computational, and experimental studies of the mechanical behaviors of the soft-hinge Kiri-MM E-armor demonstrate the merits of this design, i.e., stretchability, conformability, and protectability, as applied to flexible electronics. Deploying a conductive soft material at the hinges enables facile wiring strategies for large-scale circuit arrays. Functional E-armor systems for controllable display and sensing purposes provide simple examples of a wide spectrum of applications of this concept.