Twisting Kelvin cells for enhanced vibration control

This study introduces a minimalist design strategy to engineer wave propagation in cellular metamaterials by applying a single-parameter twist to the classical Kelvin unit cell. By breaking the cell’s symmetry while preserving its lattice topology, this geometric modification activates and tunes band-gap frequencies with up to a 9% mass increase, without introducing explicit inertial elements or added geometric complexity, enabling wave-filtering behavior absent in the untwisted reference configuration. The proposed strategy employs complex-valued Bloch–Floquet analysis of quasi-one-dimensional periodic chains, revealing symmetry-breaking triggers that activate two distinct wave-attenuation mechanisms: a complete Bragg-type and a polarization-dependent band gap arising from longitudinal–torsional mode coupling, both narrow but induced with negligible mass increment. These findings are substantiated by a physics-driven analytical model that captures the mode-coupling-induced avoided crossings and provides key insight into the wave characteristics of twisted Kelvin-cell architectures. Transmission measurements on SLA-printed three-cell specimens validate the predictive fidelity of this approach, revealing up to 20 dB of wave attenuation. We show that accounting for material viscoelasticity is essential for accurate prediction, as idealized linear-elastic models cannot capture band-gap frequencies in polymer-based chains. Overall, we show that modest, well-defined modifications to a classical parent geometry yield tunable, mass-efficient wave-filtering performance. This offers a tractable design strategy for vibration control in lightweight lattices.