Transient acoustic wave in self-similar porous material having rigid frame: Low frequency domain

Berbiche, Amine; Fellah, M.; Fellah, Zine El Abiddine; Ogam, Erick; Mitri, F.G.; Dépollier, Claude

doi:10.1016/j.wavemoti.2016.07.015

Cited by 11 publications

(13 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Discarded feathers met the core characteristics of fractal theory in morphological characteristics and had strictly statistical self-similarity [22]. Self-similarity was a typical property of fractal objects: at any scale one could find a small piece of the object that was similar to the whole in a deterministic or stochastic sense [23]. Therefore, the sound absorption performance of discarded feathers could be solved by the fractal method.…”

Section: Resultsmentioning

confidence: 99%

Sound Absorption Properties of DFs/EVA Composites

Lyu

Liu

et al. 2019

Polymers

View full text Add to dashboard Cite

Using discarded feather fibers (DFs) and ethylene vinyl acetate (EVA) copolymer, the DFs/EVA composites with good sound absorption performance were prepared by hot-pressing method. The effects of hot-pressing temperature, mass fraction of DFs, density and thickness of composites on the sound absorption properties were studied by the controlling variable method. The sound absorption properties of the composites were studied by the transfer function method, and under the optimized technological conditions, the sound absorption coefficient of the composites was above 0.9 and the sound absorption band was wide. According to the box counting method based on the fractal theory, the fractal dimension of DFs/EVA sound absorption composites was calculated through Matlab programming, and the relationship between the fractal dimension and the mass fraction of DFs, the volume density of the composites were analyzed, then the quantitative relationship between the fractal dimension and the maximum sound absorption coefficient was deduced, which played a major role in the sound absorption design of porous sound absorption materials.

show abstract

Section: Resultsmentioning

confidence: 99%

Sound Absorption Properties of DFs/EVA Composites

Lyu

Liu

et al. 2019

Polymers

View full text Add to dashboard Cite

show abstract

“…The principle of least action, based on the variational method, makes it possible to determine the equations of motion by doing an integral calculation. This method [35,37] is used to establish the equation of propagation of a wave in a porous medium along a direction x, of non-integer dimension D, the generalisation to a space consisting of three directions can be done immediately thanks to the product of measurements [34]. The corresponding Lagrangian L is a functional of the eld ψ(x, t) considered (which can be a pressure eld for example), and of its temporal and spatial derivatives which we note ∂ t ψ(x, t) and ∂ x ψ(x).…”

Section: Modelmentioning

confidence: 99%

“…In the case of a homogeneous porous material with a rigid frame, which is a particular case of the Biot Theory [36], the expression of the Lagrangian density is given by [35,37]…”

Section: Modelmentioning

confidence: 99%

Reflection and transmission of transient ultrasonic wave in fractal porous material: Application of fractional calculus

Fellah

Ogam

et al. 2021

Wave Motion

Self Cite

View full text Add to dashboard Cite

This paper provides a time domain model for the propagation of transient ultrasonic waves in a self-similar porous material having a rigid frame. This model is based on the formalism of Stillinger-Palmer-Stavrinou, which consists in modeling the fractal material as a porous medium with a non-integer dimensional space. This paper is devoted to the time-domain analytical calculus of the reection and transmission operators that are expressed in terms of Mittag-Leer functions. A sensitivity numerical study using ultrasonic reected and transmitted waves is performed, highlighting the eect of of the material's physical parameters (fractal dimension, tortuosity, viscous characteristic length and porosity) on the waveforms.

show abstract

“…25,26 The Voronina model presented the empirical formula of the structural characteristic parameter (Q) based on the apparent porosity (H) and average pore size (D) of the material. On this basis, the formula of the characteristic impedance (Z c ) and propagation constant (k) was further established by analyzing the experimental data, as shown in Equations (7)(8)(9)(10)(11)(12). 25,26 where μ = 1.85 × 10 −5 is the dynamic viscosity coefficient, r is the wave number, and B is a parameter that depends on the characteristics of the structure.…”

Section: Simulated Mechanism Modelmentioning

confidence: 99%

“…The sound energy is dissipated by thermal loss due to the friction of air molecules with the pore walls, and viscous loss resulting from the viscosity of airflow within the materials. 11,12 Therefore, the apparent porosity and pore size are key determinants of the sound-absorption properties of porous materials. 5 Numerous technologies have been developed to produce porous sound-absorbing ceramics, such as organic template impregnation, freezing casting, foaming, templating, and gelcasting methods.…”

Section: Introductionmentioning

confidence: 99%

Open‐cell porous sound‐absorbing ceramics prepared by a new procedure that combines foamed and templated methods

Tian

Tang

Wang

et al. 2020

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

Low-grade nonmetal ore, mainly magmatic soil and tuff, was used to prepare porous sound-absorbing ceramics. A new processing method that combines the foaming and templating methods was used to produce open-cell porous ceramics. Silicon carbide and carbon powders were used as the foaming agent and template agent, respectively, and their effects on open-cell preparation and sound-absorption properties were also investigated. The results showed that sound-absorption performance was closely related to the apparent porosity (H). Compared with either foaming or template methods, the new method incorporating both processes increased the sound-absorption coefficient (α) and H by 51%-258% and 69%-728%, respectively. Optimum sound absorption of the ceramics, that is, α = 0.68, noise reduction coefficient (NRC) = 0.48, and H = 50.22%, were obtained at foaming agent contents (FACs) of 1.5 wt% and template agent contents (TACs) of 4 wt%. The Delany-Bazley and Voronina models were selected to simulate the sound-absorption coefficients and the latter one fitted well with our experimental results. K E Y W O R D Scombined foamed and templated method, open cell, sound-absorption mechanism, sound-absorbing ceramics, voronina model

show abstract

Transient acoustic wave in self-similar porous material having rigid frame: Low frequency domain

Cited by 11 publications

References 46 publications

Sound Absorption Properties of DFs/EVA Composites

Sound Absorption Properties of DFs/EVA Composites

Reflection and transmission of transient ultrasonic wave in fractal porous material: Application of fractional calculus

Open‐cell porous sound‐absorbing ceramics prepared by a new procedure that combines foamed and templated methods

Contact Info

Product

Resources

About