Vibroacoustic optimization of anti-tetrachiral and auxetic hexagonal sandwich panels with gradient geometry

Ranjbar, Mostafa; Boldrin, Luca; Scarpa, Fabrizio; Neild, Simon A; Patsias, Sophoclis

doi:10.1088/0964-1726/25/5/054012

Cited by 50 publications

(26 citation statements)

References 40 publications

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“…Furthermore, the fine parametric tunability of the microstructural inertia and stiffness allows the systematic employment of chiral and anti-chiral materials to realize efficient and versatile phononic filters, elastic waveguides and acoustic diodes [10], [11], [12], [13], [14]. Within this challenging framework, the optimal design of the micromechanical properties opens interesting research perspectives towards the theoretical conceptualization and experimental validation of a new generation of smart materials targeted at innovative engineering applications, including impact absorption, negative refraction, shape morphing, wave trapping, vibration shielding, noise silencing and invisibility cloaking [15], [16], [17], [18], [19], [20].…”

Section: Introductionmentioning

confidence: 99%

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

et al. 2019

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Microstructured honeycomb materials may exhibit exotic, extreme and tailorable mechanical properties, suited for innovative technological applications in a variety of modern engineering fields. The paper is focused on analysing the directional auxeticity of tetrachiral materials, through analytical, numerical and experimental methods. Theoretical predictions about the global elastic properties have been successfully validated by performing tensile laboratory tests on tetrachiral samples, realized with high precision 3D printing technologies. Inspired by the kinematic behaviour of the tetrachiral material, a newly-design bi-layered topology, referred to as bi-tetrachiral material, has been theoretically conceived and mechanically modelled. The novel topology virtuously exploits the mutual collaboration between two tetrachiral layers with opposite chiralities. The bi-tetrachiral material has been verified to outperform the tetrachiral material in terms of global Young modulus and, as major achievement, to exhibit a remarkable auxetic behaviour. Specifically, experimental results, confirmed by parametric analytical and computational analyses, have highlighted the effective possibility to attain strongly negative Poisson ratios, identified as a peculiar global elastic property of the novel bi-layered topology.

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Section: Introductionmentioning

confidence: 99%

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

et al. 2019

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“…The idea of metamaterial is inspired by nature, as it is seen in the structure of some woods, bones and hard tissue of some animals. In engineering applications, it has been proved that these structures have a promising performance in shock and impact absorption 35,36 , improving the bending stiffness of thin-walled structures 37 and vibro-acoustics performance of sandwich panels 38,39 .…”

Section: Results Of This Study Can Open a New Path To Application Of mentioning

confidence: 99%

Study in circular auxetic structures for efficiency enhancement in piezoelectric vibration energy harvesting

Eghbali

Younesian

Moayedizadeh

et al. 2020

Sci Rep

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Piezoelectric (PZT) components are one of the most popular elements in vibration sensing and also energy harvesting. They are very well established, cost effective and available in different geometries however there are still several challenges in their application particularly in vibration energy harvesting. They are normally narrow-band elements and work in high-frequency range. Their efficiency and power extraction density are also generally low compared with different electromagnetic techniques. Auxetic structures are proposed here to enhance efficiency of the piezoelectric circular patches in vibration energy harvesting. These kinds of patches namely PZT buzzers are inexpensive (less than 10 USD) elements and easily available. Two novel circular auxetic substrates are proposed to improve power extraction capacity of the conventional piezoelectric buzzers. Negative Poison’s ratio of the proposed meta-structure helps in efficiency enhancement. The concept is introduced, analyzed and verified through the finite element modeling and experimental testing. The idea is proved to work by comparing the harvested electrical power in the auxetic design against the conventional plain system. A parametric study is then carried out and effects of important electrical and geometrical parameters as well as the material property on the power extraction efficiency are assessed to arrive at optimum parameters. It is shown that by employing the auxetic design, a remarkable improvement in the harvested power is achievable. It is shown that for the two proposed auxetic designs, at the resonance frequency, we could reach to 10.2 and 13.3 magnification factor with respect to the plain energy harvester. Another important feature is that the resonant frequency in these new designs is very much lower than the conventional resonators. Results of this study can open a new path to application of inexpensive PZT buzzers in large-scale vibration energy harvesting.

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“…[39] One of the structures, which has attracted a significant amount of attention, is the anti-tetrachiral system, including development of analytical models for its mechanical properties as well as results from finite-element analysis (FEA). [11,12] Other studies considered the dynamic response of the structure to mechanical oscillations [40,41] and the effect of random variation in the nodes or rotating centers. [42] More recently, it was shown that the structure can be extended to three dimensions either by connecting ligaments at common rotating centers [43] or by connecting ligaments at their intersection (see Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Tuning the Mechanical Properties of the Anti‐Tetrachiral System Using Nonuniform Ligament Thickness

Farrugia

Gatt

Grima‐Cornish

2020

Physica Status Solidi (b)

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The mechanical properties of the anti-tetrachiral structure having the thickness of the ligament changing symmetrically around the center are investigated using analytical and numerical methods. For the purpose of deriving a theoretical model, the Euler-Bernoulli beam theory is used to determine the relation among the acting moment, the angle of rotation of the nodes, and the bending energy stored. Analysis of the results indicates that a change in geometry has a minor effect on Poisson's ratio, if any at all; however, it can result in relatively large changes in Young's modulus. Hence, it is shown that the mechanical properties can be altered selectively by adjusting the geometric features of chiral structures. The indications of the analytical model are validated using numerical methods for different values of the geometric parameters and are found to be in good agreement. In the process, it is shown that there are regions of the parameter space where the mechanical properties of the anti-tetrachiral are insensitive to variations in certain geometric dimensions.

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Vibroacoustic optimization of anti-tetrachiral and auxetic hexagonal sandwich panels with gradient geometry

Cited by 50 publications

References 40 publications

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

Study in circular auxetic structures for efficiency enhancement in piezoelectric vibration energy harvesting

Tuning the Mechanical Properties of the Anti‐Tetrachiral System Using Nonuniform Ligament Thickness

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