기성 기계 부품 기반 가변 밴드갭 국부공진 메타물질의 설계

초록

Locally resonant metamaterials (LRMs) are artificial periodic structures that effectively suppress elastic wave propagation within specific frequency bands, known as bandgaps, by utilizing local resonance phenomena of embedded mass-spring resonators.​ Conventional LRMs, however, are limited by fixed bandgap characteristics once fabricated, necessitating re-fabrication or complex processing for any frequency adjustment. This study proposes a novel, tunable bandgap LRM architecture constructed from readily available, off-the-shelf mechanical components: a plastic bolt serving as the stiffness element and a changeable steel square nut as the mass element. Numerical analyses, employing Bloch-Wave theory for dispersion curve calculations and finite element methods for frequency response function (FRF) simulations, validate the systematic tunability of the bandgap. Specifically, by simply adjusting the nut's position along the bolt, the bandgap's central frequency and bandwidth can be effectively modulated without re-machining. Experimental validation on an 8x8 finite array structure confirms the formation and adjustable nature of these bandgaps, demonstrating a consistent shift in the bandgap frequency range in response to nut position changes, which aligns well with numerical predictions. This approach offers a practical, low-cost, and easily manufacturable solution for vibration mitigation, enabling on-site adaptable designs for targeted frequency ranges.

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