Acoustic properties of auxetic foams

Chekkal, I.; Remillat, Chrystel D L; Scarpa, Fabrizio

doi:10.2495/hpsm120111

Cited by 16 publications

(8 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the viewpoint of mechanical property, auxetic materials possess higher shear modulus, greater indentation resistance, better energy absorption ability, and stronger crack resistance than the conventional materials 13,14 . From the viewpoint of acoustic property, auxetic porous metamaterials exhibit better low‐frequency sound absorption property than conventional porous materials 15,16,17 . Also, the auxetic phononic crystals are demonstrated to have lower frequency phononic bandgaps than phononic crystals with positive Poisson's ratio 18 …”

Section: Introductionmentioning

confidence: 99%

Highly tailorable electromechanical properties of auxetic piezoelectric ceramics with ultra‐low porosity

et al. 2020

View full text Add to dashboard Cite

Conventional porous piezoelectric ceramics can possess superior figures of merit only at very high values of porosity, leading to bad fragileness, small stiffness, low toughness, and the difficulty of polarization. To this end, this study for the first time shows that it is possible that the piezoelectric ceramic with ultra‐low porosity is capable of superior figures of merit based on the concept of auxetic piezoelectric ceramics. Owing to the ultra‐low porosity and auxetic effect, the auxetic piezoelectric ceramic shall also possess larger stiffness, higher toughness, and is more easily polarized. First, the auxetic piezoelectric ceramic with ultra‐low porosity is proposed to achieve highly tunable electromechanical properties on the basis of the rotating square mechanism. Then, using a multiscale finite element method, the effects of geometric architecture and polarization directions on the electromechanical properties including Poisson's ratios, elastic coefficients, piezoelectric stress coefficients, dielectric coefficients, and figures of merit in the auxetic piezoelectric ceramics are investigated in detail. Furthermore, the stress fields in conventional and proposed porous piezoelectric ceramics subjected to mechanical and electrical loads are compared and discussed. Finally, it can be concluded that the auxetic piezoelectric ceramic exhibits (a) giant negative Poisson's ratios (smaller than ‐5), (b) negative elastic coefficients, (c) more extensible, higher piezoelectric sensitivity, lower acoustic impedance, stronger crack resistance than conventional porous piezoelectric ceramics with the same porosity, and (d) larger stiffness than conventional porous piezoelectric ceramics with similar figures of merit.

show abstract

Section: Introductionmentioning

confidence: 99%

Highly tailorable electromechanical properties of auxetic piezoelectric ceramics with ultra‐low porosity

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Other enhanced properties are mechanical hardness, toughness, and stiffness [ 11 ]. In terms of the dynamic performance, auxetic materials also show an overall superiority regarding damping and acoustic properties compared to the conventional materials [ 12 , 13 ]. It has been found that auxetic honeycomb structures not only show an improvement of transmission loss factors but also show an isotropic acoustic signature at lower modes and also have isotropic mechanical properties [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Auxetic Cellular Material Consisting of Re-Entrant Hexagonal Honeycombs

Zhang

Yang

2016

Materials

View full text Add to dashboard Cite

A preliminary study of the mechanical properties of auxetic cellular material consisting of re-entrant hexagonal honeycombs is presented. For different scales of the honeycombs, the finite element method (FEM) and experimental models are used to perform a parametric analysis on the effects of the Poisson’s ratio (cell angle) and the relative density (cell thickness) of honeycombs on bearing capacity and dynamic performance of the auxetic material. The analysis demonstrates that the ultimate bearing capacity of the presented auxetic cellular material is scale-independent when the Poisson’s ratio and the relative density are kept constant. The relationship between the geometric parameters and vibration level difference of the honeycombs is also revealed, which can be divided into two converse parts around the Poisson’s ratio v=−1.5. When v is smaller than −1.5, increasing the cell thickness leads to an increase in the vibration level difference of the honeycombs. Moreover, the dynamic performance of thin-walled honeycombs is greatly influenced by the scale of the honeycombs, especially for the ones with small Poisson’s ratio. These conclusions are verified by a frequency response test and a good agreement between the numerical results and experimental data is achieved.

show abstract

“…Most studies of the acoustic properties of polyolefin foams are limited to the study of sound absorption under various conditions and its dependence on porosity, apparent density, tortuosity of pores, and radiation frequency [1][2][3][4][5][6][7][8][9]. A number of studies [1][2][3][4][5][6][7][8][9] show the possibility of improving the acoustic characteristics (sound absorption, sound attenuation, and vibration damping property) by optimizing the structure and synthetic formula with various inorganic and organic fillers [3,[10][11][12][13]. The influence of porosity and tortuosity of pores on the speed of sound, Poisson's ratio, elastic modulus, and radiation frequencies is studied [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Nonuniformity of Elastic Properties of Sheets Made from Closed-Сell Polyolefin Foams by Acoustic Method

Bogdan

Злобин

Муравьева

et al. 2021

Prib. metody izmer.

View full text Add to dashboard Cite

The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method.The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming).It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy.Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.

show abstract

Acoustic properties of auxetic foams

Cited by 16 publications

References 16 publications

Highly tailorable electromechanical properties of auxetic piezoelectric ceramics with ultra‐low porosity

Highly tailorable electromechanical properties of auxetic piezoelectric ceramics with ultra‐low porosity

Mechanical Properties of Auxetic Cellular Material Consisting of Re-Entrant Hexagonal Honeycombs

Evaluation of Nonuniformity of Elastic Properties of Sheets Made from Closed-Сell Polyolefin Foams by Acoustic Method

Contact Info

Product

Resources

About