Design, fabrication and experimental validation of a MEMS periodic auxetic structure

Zega, Valentina; Nastro, Alessandro; Ferrari, Maurizio; Ardito, Raffaele; Ferrari, Vittorio; Corigliano, Alberto

doi:10.1088/1361-665x/ab30be

Cited by 15 publications

(6 citation statements)

References 45 publications

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“…Moreover, despite the limitations imposed by the compatibility of the unit cells, the design space of aperiodic metamaterials is huge and not restricted to the configurations supporting the mode separation concept. Finally, the extension of the aperiodic metamaterial concept to the microscopic scale is desirable 32 , in view of the possible application as mechanical or acoustic filter in the field of Micro and Nano Electro-Mechanical Systems (MEMS/NEMS).…”

Section: Discussionmentioning

confidence: 99%

A design strategy to match the band gap of periodic and aperiodic metamaterials

Dalessandro

Krushynska

Ardito

et al. 2020

Sci Rep

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The focus of this paper is on elastic metamaterials characterised by the presence of wide sub-wavelength band gap. In most cases, such mechanical property is strictly connected to the periodic repetition of the unit cell. Nonetheless, the strict periodicity requirement could represent a drawback. In this paper, we present a design strategy for aperiodic elastic metamaterials in order to achieve the same performances as for the periodic counterparts. This is done by exploiting the concept of separation of modes for different building blocks, arranged in aperiodic fashion. A theoretical explanation is provided, as well as numerical simulations; the concept is validated by means of a set of experimental tests on prototypes that are realized via additive manufacturing.

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Section: Discussionmentioning

confidence: 99%

A design strategy to match the band gap of periodic and aperiodic metamaterials

Dalessandro

Krushynska

Ardito

et al. 2020

Sci Rep

Self Cite

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“…The innovative MEMS electrically tunable mechanical filter recently proposed in [28,29] is here employed to demonstrate the efficiency of the proposed fabrication imperfection identification procedure.…”

Section: Mechanical Designmentioning

confidence: 99%

Identification of MEMS Geometric Uncertainties through Homogenization

Faraci

Zega

Nastro

et al. 2022

Micro

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Fabrication imperfections strongly influence the functioning of Micro-Electro-Mechanical Systems (MEMS) if not taken into account during the design process. They must be indeed identified or precisely predicted to guarantee a proper compensation during the calibration phase or directly in operation. In this work, we propose an efficient approach for the identification of geometric uncertainties of MEMS, exploiting the asymptotic homogenization technique. In particular, the proposed strategy is experimentally validated on a MEMS filter, a device constituted by a complex periodic geometry, which would require high computational costs if simulated through full-order models. The complex periodic structure is replaced by an equivalent homogeneous medium, allowing a fast optimization procedure to identify imperfections by comparing a simplified analytical model with the experimental data available for the MEMS filter. The actual over-etch, obtained after the release phase, and the electrode offset of a fabricated MEMS filter are effectively identified through the proposed strategy.

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“…However, the auxetic material with negative Poisson's ratio presents expansion under uniaxial tensile force [1]. Auxetic structures such as chiral structure, re-entrant structure, rotating rigid structure [2][3][4], could be designed for applications to micro devices [5], medical device [6], aerospace [7], and sensors [8,9]. Other than designed structures, negative Poisson's ratio was frequently observed in fibrous materials [10].…”

Section: Introductionmentioning

confidence: 99%

Humidity response of a capacitive sensor based on auxeticity of carbon nanotube-paper composites

Qian

Sakthivelpathi

et al. 2022

Nano Ex.

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Auxetic materials showing a negative Poisson’s ratio can offer unusual sensing capabilities due to drastic percolation changes. This study presents the capacitive response of wet-fractured carbon nanotube paper composites in exposure to humidity. A strained composite strip is fractured to produce numerous cantilevers consisting of cellulose fibers coated with carbon nanotubes. During stretching, the thin composite buckles in the out-of-plane direction, which causes auxetic behavior to generate the radially structured electrodes. The crossbar junctions forming among the fractured electrodes significantly increase capacitance and its response to humidity as a function of sensor widths. The molecular junctions switch electric characteristics between predominantly resistive- and capacitive elements. The resulting capacitive response is characterized for humidity sensing without the need for an additional absorption medium. The normalized capacitance change (ΔC/C) exhibits a sensitivity of 0.225 within the range of 40~80 % relative humidity. The novel auxetic behavior of a water-printed paper-based nanocomposite paves the way for inexpensive humidity and sweat sensors.

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Design, fabrication and experimental validation of a MEMS periodic auxetic structure

Cited by 15 publications

References 45 publications

A design strategy to match the band gap of periodic and aperiodic metamaterials

A design strategy to match the band gap of periodic and aperiodic metamaterials

Identification of MEMS Geometric Uncertainties through Homogenization

Humidity response of a capacitive sensor based on auxeticity of carbon nanotube-paper composites

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