Study of Non-Periodical Mechanical Metamaterials: Design and Application

Huo, Jindong; Wang, Ningzhen; Peng, Hongtao

doi:10.54097/ajst.v3i3.2920

Cited by 2 publications

(2 citation statements)

References 30 publications

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“…One important feature is the local resonance induced sub-wavelength bandgap, which is orders of magnitude lower than the Bragg scattering bandgap [21][22][23]. Due to the preserve of bandgap that forbids wave propagation in certain design frequencies [22,[24][25][26][27][28][29], manipulating wave transmission can be realized by tuning the band structures, which leaves great degrees of freedom in optimizing the topology and structure.…”

Section: Introductionmentioning

confidence: 99%

Data-driven design and optimization of ultra-tunable acoustic metamaterials

Huo

Wang

Wang³

et al. 2023

Smart Mater. Struct.

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This paper presents a data-driven design and optimization of acoustic metamaterials with three-phase materials for highly tunable wave transmission. The geometry of representative unitcell is defined by the trigonometric series function to describe an arbitrary shape with symmetry, which enables the unitcell to achieve a large sub-wavelength bandgap. We propose a lightweight and efficient algorithm, “decoupled gradient decent (DGD)”, to search for the optimal design and uncover the “best” shape features – the interface curvature – in tuning the wave transmission. As a result, the host composite can partly overlap the individual cell’s bandgap and achieve a wide frequency gap that forbids wave transmission, namely a passive tunability. Another advantage of the trigonometric series designed shape is the high flexibility. A slight surface pressure obviously deforms the unitcell and shifts its band structure. Our simulation shows that a moderate pressure dramatically changes the frequency forbidding gap for both traversal and longitudinal wave transmissions, which indicates an active tunability. The surface deformation can be applied by either a mechanical pressure or external electric field if the composite uses a dielectric substrate. Therefore, this study opens a sandbox of manipulating wave transmission through the topology and structure optimization in applications such as seismic damping (Hz), noise insulating (kHz) and ultrasound imaging (MHz).

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Section: Introductionmentioning

confidence: 99%

Data-driven design and optimization of ultra-tunable acoustic metamaterials

Huo

Wang

Wang³

et al. 2023

Smart Mater. Struct.

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“…The arc interacting on the electrodes is well studied for many engineering applications such as circuit breakers [1][2][3][4][5][6][7][8], plasma etching and welding [9][10][11], materials fabrication [12][13][14][15][16][17][18] and process the metal due to various kinds of damage. The arc root jumping is also frequently observed in arcs' propagation along the rail electrode's like in circuit breakers and plasma actuators .…”

Section: Introductionmentioning

confidence: 99%

Instability and dynamic behavior of arc attachments on electrodes and the effect on electrode erosion

Li¹,

Liang²,

Zhang³

et al. 2023

IJE

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Plasma interacting with electrodes is one of the most challenging issues in many industrial applications, such as power-interruption and plasma-metal erosion. Because of the concentration of arc attachments (root) and the voltage drop across the plasma sheath layer, the arc roots consume great amount of energy, which subsequently will increase the local temperature and erode the electrodes. Due to the nonequilibrium condition at plasma sheath, it is very difficult to quantitatively estimate the arc root temperature profile. The recognition of arc roots behavior, like instability and pattern formation, is important to estimate the electrode erosion. The potential drop arising through the sheath (double layer) is nonuniform. Due to thermionic field emission, the strong flux of charge carriers through the sheath will cause instability of the double layer, which weakens the inner potential gradient. As a result, the strong current dependent potential drop features a negative resistance. The existence of negative resistance causes the instability of arc attachments in the forms of immobility and constriction. Their interdependence between local current density and potential drop gives rise to the arc root formation that concentrates the energy into a small spot. Owing to the negative resistance, any perturbation will cause the current density in the sheath to grow to approximately infinity or decay to vanish, namely arc root formation or extinction. Thereby, the arc root instability provides the basis for the dynamic behavior of arc attachments and detachments on the electrodes, which will help to understand electrode erosion and avoid the damage from the arc plasma in engineering applications.

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Study of Non-Periodical Mechanical Metamaterials: Design and Application

Cited by 2 publications

References 30 publications

Data-driven design and optimization of ultra-tunable acoustic metamaterials

Data-driven design and optimization of ultra-tunable acoustic metamaterials

Instability and dynamic behavior of arc attachments on electrodes and the effect on electrode erosion

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