Magnetic coupling transforms random snapping into ordered sequences in soft metamaterials

TL;DR

Magnetic interactions in soft materials enable controlled, sequential snapping instead of random behavior.

Contribution

Magnetic coupling enables deterministic, multistep mechanical responses in soft metamaterials.

Findings

Intralayer magnetized units produce nonlinear force-displacement responses with hysteresis.

Interlayer magnetic interactions enable directional snapping through chain reactions.

This mechanism allows adaptive materials for robotics and biomedical applications.

Abstract

Mechanical metamaterials achieve multistep, programmable responses through sequential deformation driven by snapping instabilities, yet these sequences are typically governed by unavoidable imperfections, resulting in random and uncontrollable behavior. Here, we harness intra- and interlayer magnetic interactions coupled with elasticity to reprogram the ordering of sequential buckling instabilities in kirigami-inspired soft magnetic metamaterials. In single-layer systems, intralayer coupling among magnetized units produces random snapping sequences but generates strongly nonlinear-spiked force-displacement responses with pronounced hysteresis, in contrast to the simultaneous buckling of unmagnetized sheets. In multilayer assemblies, interlayer magnetic interactions trigger chain reaction–like propagation, transforming randomness into robust, directional snapping across structures. This mechanism establishes a paradigm for deterministic, multistep mechanical responses without continuously applied fields and opens avenues for adaptive materials in energy dissipation, waveguiding, reconfigurable soft robotics, and biomedical devices.

Internal magnetic interactions transform random sequential snapping into deterministic ordering in planar soft metamaterials.

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