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This study introduces a mechanical spectrum analyzer (MSA) inspired by the tonotopic organization of the basilar membrane (BM), designed to achieve two critical features. First, it replicates the traveling-wave behavior of the BM, characterized by energy dissipation without reflections at the boundaries. Second, it enables the physical encoding of the wave energy into distinct spectral components. Moving beyond the conventional focus on metamaterial design, this research investigates wave propagation behavior and energy dissipation within metastructures, with particular attention to how individual unit cells absorb energy. To achieve these objectives, a metastructural design methodology is employed. Experimental characterization of metastructure samples with varying numbers of unit cells is performed, with reflection and absorption coefficients used to quantify energy absorption and assess bandgap quality. Simulations of a basilar membrane-inspired structure incorporating multiple sets of dynamic vibration resonators (DVRs) demonstrate frequency selectivity akin to the natural BM. The design features four types of DVRs, resulting in stepped bandgaps and enabling the MSA to function as a frequency filter. The findings reveal that the proposed MSA effectively achieves frequency-selective wave propagation and broad bandgap performance. The quantitative analysis of energy dissipation, complemented by qualitative demonstrations of wave behavior, highlights the potential of this metastructural approach to enhance frequency selectivity and improve sound processing. These results lay the groundwork for future exploration of 2D metastructures and applications such as energy harvesting and advanced wave filtering.
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This content will become publicly available on May 15, 2026
Mass conserved metastructure for vibration suppression via bandgap tuning
Architected materials can be synthesized to effectively control elastic wave propagation via bandgap engineering, which is essential for vibration mitigation and sound attenuation applications. Mechanisms for controlling elastic waves include Bragg scattering resulting from structural periodicity and local resonance effects, both of which were employed to create bandgaps. It is also shown that with careful design, the Bragg- and resonance-type bandgaps can be combined to achieve broader stopbands. Structures that use these bandgap mechanisms, especially those utilizing local resonators, add mass to the system, which could be highly undesirable for many engineering applications where mass considerations directly impact the system efficiency. To address this shortfall and advance the state of the art, this research proposes a mass-conserved design concept for metastructures that utilize both Bragg-type and local resonance bandgap mechanisms to create enhanced bandgap characteristics within the structure. The mass-conserved design is achieved by employing the existing system mass to create geometries that allow for bandgap generation, rather than adding mass to the structure as seen in traditional metastructure systems. The developed methodology shows that broader stopbands can be created without adding mass to the overall system, and this research identifies critical design parameters in order to achieve effective mass-conserved bandgap engineering compared to traditional metastructures designs. This method of mass-conserved metastructure design is shown to be effective when applied to various means of tuning that further enhance the bandgap regions, including the use of multiple-degree-of-freedom resonators and hybrid unit cells. These advancements provide a mass-constrained approach to bandgap engineering methods, expanding our ability to create lighter and more efficient structures with effective vibration control.
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- Award ID(s):
- 1935216
- PAR ID:
- 10640768
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Mechanical systems and signal processing
- ISSN:
- 1096-1216
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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