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Article

Yalei Liu, Xiaohui Gu, Yunmeng Lian and Heng Liu

The purpose of this paper is to demonstrate the theoretical relationship between the layout of four‐sensor dynamic acoustic array tracking system and systematic…

Abstract

Purpose

The purpose of this paper is to demonstrate the theoretical relationship between the layout of four‐sensor dynamic acoustic array tracking system and systematic observation accuracy, and provide an algorithm to determine the optimal arrangement of four‐sensor acoustic array and an indicator to evaluate acoustic array system measurement accuracy.

Design/methodology/approach

In the present paper, the measurement principle of the four‐sensor dynamic acoustic array tracking system is analyzed, and the system observation model and the conversion relationship between models are established. Subsequently, the optimization algorithm for the four‐sensor dynamic acoustic array is deduced, the theoretical optimal arrangement of the four‐sensor dynamic acoustic array tracking measurement system is obtained based on the optimal position dilution of precision function (PDOPF) of 2D target, and the static experimental study on sound‐source bearing estimation is designed. The theoretical results are compared with the experimental results of the present study.

Findings

The measurement accuracy of the four‐sensor dynamic acoustic array tracking system is largely dependent on the layout of the acoustic sensor. Theoretical studies and experimental results demonstrated that an optimal PDPOF can be used to analyze the rationality of the layout. It can also serve as an indicator for the layout of the four‐sensor dynamic acoustic array tracking system.

Originality/value

The PDOPF value is presented as an indicator for the evaluation of the four‐sensor dynamic acoustic array systematic observation accuracy based on theoretical analysis. The feasibility of the indicator and the rationality of the sensor layout in practical engineering application are verified through experimental studies on sound‐source bearing estimation. The higher the PDOPF value is, the lower the accuracy of the system will be.

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Article

Mansoor Ahmad, Ayhan Bozkurt and Omid Farhanieh

This paper aims to Separation and sorting of biological cells is desirable in many applications for analyzing cell properties, such as disease diagnostics, drugs delivery…

Abstract

Purpose

This paper aims to Separation and sorting of biological cells is desirable in many applications for analyzing cell properties, such as disease diagnostics, drugs delivery, chemical processing and therapeutics.

Design/methodology/approach

Acoustic energy-based bioparticle separation is a simple, viable, bio-compatible and contact-less technique using, which can separate the bioparticles based on their density and size, with-out labeling the sample particles.

Findings

Conventionally available bioparticle separation techniques as fluorescence and immunomagnetic may cause a serious threat to the life of the cells due to various compatibility issues. Moreover, they also require an extra pre-processing labeling step. Contrarily, label-free separation can be considered as an alternative solution to the traditional bio-particle separation methods, due to their simpler operating principles and lower cost constraints. Acoustic based particle separation methods have captured a lot of attention among the other reported label-free particle separation techniques because of the numerous advantages it offers.

Practical implications

This study tries to briefly cover the developments of different acoustic-based particle separation techniques over the years. Unlike the conventional surveys on general bioparticles separation, this study is focused particularly on the acoustic-based particle separation. The study would provide a comprehensive guide for the future researchers especially working in the field of the acoustics, in studying and designing the acoustic-based particle separation techniques.

Originality/value

The study insights a brief theory of different types of acoustic waves and their interaction with the bioparticles is considered, followed by acoustic-based particle separation devices reported till the date. The integration of acoustic-based separation techniques with other methods and with each other is also discussed. Finally, all major aspects like the approach, and productivity, etc., of the adopted acoustic particle separation methods are sketched in this article.

Details

World Journal of Engineering, vol. 16 no. 6
Type: Research Article
ISSN: 1708-5284

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Article

Mengna Cai, Hongyan Tian, Haitao Liu and Yanhui Qie

With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue…

Abstract

Purpose

With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue. Therefore, it is the most important task to develop efficient sound attenuation barriers, especially for the low-frequency audible range. However, low-frequency sound attenuation is usually difficult to achieve for the constraints of the conventional mass-density law of sound transmission. The traditional acoustic materials are reasonably effective at high frequency range. This paper aims to discuss this issue.

Design/methodology/approach

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. In this paper, the finite element method is used to study the low-frequency sound insulation performances of the coupled-membrane type acoustic metamaterial (CMAM). It consists of two identical tensioned circular membranes with fixed boundary. The upper membrane is decorated by a rigid platelet attached to the center. The sublayer membrane is attached with two weights, a central rigid platelet and a concentric ring with inner radius e. The influences of the distribution and number of the attached mass, also asymmetric structure on the acoustic attenuation characteristics of the CMAM, are discussed.

Findings

In this paper, the acoustic performance of asymmetric coupled-membrane metamaterial structure is discussed. The influences of mass number, the symmetric and asymmetry structure on the sound insulation performance are analyzed. It is shown that increasing the number of mass attached on membrane, structure exhibits low-frequency and multi-frequency acoustic insulation phenomenon. Compared with the symmetrical structure, asymmetric structure shows the characteristics of lightweight and multi-frequency sound insulation, and the sound insulation performance can be tuned by adjusting the distribution mode and location of mass blocks.

Originality/value

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. How to effectively broaden the acoustic attenuation band at low frequency is still a problem. But most of researchers focus on symmetric structures. In this study, the asymmetric coupled-membrane acoustic metamaterial structure is examined. It is demonstrated that the asymmetric structure has better sound insulation performances than symmetric structure.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 5
Type: Research Article
ISSN: 1573-6105

Keywords

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Article

Izhar and Farid Ullah Khan

The purpose of this paper is to develop a novel electromagnetic-based acoustic energy harvester (EH) for the application of wireless autonomous sensors.

Abstract

Purpose

The purpose of this paper is to develop a novel electromagnetic-based acoustic energy harvester (EH) for the application of wireless autonomous sensors.

Design/methodology/approach

The developed acoustic EH comprises a Helmholtz resonator (HR), a suspension system that consists of a flexible membrane and a permanent magnet, a couple of coils and a coil holder. Furthermore, the HR, used in the harvester, is designed for a specific resonant frequency based on simulation carried out in COMSOL Multiphysics®.

Findings

The developed harvester is tested both in lab under harmonic sound pressure levels (SPLs) and in real environment under random SPLs. In lab, when exposed to 100 dB SPL, the harvester generated a peak power of 212 µW. Furthermore, in real environment in vicinity of electric generator, the harvester produced an output voltage of about 110 mV collectively from its both coils.

Originality/value

In this paper, a novel geometric configuration for electromagnetic-based acoustic EH is proposed. In the developed harvester, two coils are placed in it to achieve enhanced electrical output from it for the first time.

Details

Sensor Review, vol. 38 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Sui Pheng Low, Jun Ying Liu and Kok Hiong Oh

While the buildability concept and habitation comfort have been studied extensively, these have so far been examined separately. In particular, the implications which the…

Abstract

Purpose

While the buildability concept and habitation comfort have been studied extensively, these have so far been examined separately. In particular, the implications which the total building performance (TBP) concept, as part of habitation comfort, may have on buildability are as yet unknown. Arising from this lacuna, the objective of this study is to develop an understanding of the relationship between buildability and the two TBP concepts of spatial and acoustic performance.

Design/methodology/approach

In studying the relationship between the spatial and acoustic performance concepts and buildability, a base model was used to establish the baseline for comparison. This base model was adopted from the Code of Practice on Buildable Design implemented by the Building and Construction Authority (BCA) in Singapore. The incorporation of spatial and acoustic performance guidelines on the base model was examined to assess their influence on the buildability score.

Findings

Analysis for the spatial performance concept yielded a slight decrease in the buildability score after the incorporation of the guidelines. This was also the case in the acoustic performance concept, where there was a slight decrease in the buildability score. Nevertheless, the reductions do not affect the buildability score so significantly. The minimum buildability score requirements set by the BCA were still met after the incorporation of the guidelines. This seems to suggest that there is minimal effect on the buildability score arising from the implementation of both the spatial and acoustic performance concepts.

Practical implications

The study determined that the two TBP concepts of spatial and acoustic performance do not seem to have any significantly adverse effect on buildability. Building professionals can therefore incorporate appropriate spatial and acoustic performance guidelines in their architectural layout designs without compromising on buildability.

Originality/value

This study presents a better understanding of the relationship between buildability and the two TBP concepts of spatial and acoustic performance.

Details

Facilities, vol. 26 no. 1/2
Type: Research Article
ISSN: 0263-2772

Keywords

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Article

Julius Owowo and S. Olutunde Oyadiji

The purpose of this paper is to employ the acoustic wave propagation method for leakage detection in pipes. The first objective is to use acoustic finite element analysis…

Abstract

Purpose

The purpose of this paper is to employ the acoustic wave propagation method for leakage detection in pipes. The first objective is to use acoustic finite element analysis (AFEA) method to simulate acoustic wave propagation and acoustic wave reflectometry in an intact pipe and in pipes with leaks of various sizes. This is followed by the second objective which is to validate the effectiveness and the practicability of the acoustic wave method via experimental testing. The third objective involves the decomposition and de-noising of the measured acoustic waves using stationary wavelet transform (SWT). It is shown that this approach, which is used for the first time on leakage detection in pipes, can be used to identify, locate and estimate the size of a leakage defect in a pipe.

Design/methodology/approach

The research work was designed inline with best practices and acceptable standards. The research methodology focusses on five basic areas: literature review; experimental measurements; simulations; data analysis and writing-up of the study with clear-cut communication of the findings. The approach used was acoustic wave propagation-based method in conjunction with SWT for leakage detection in fluid-filled pipe.

Findings

First, the simulation of acoustic wave propagation and acoustic wave reflectometry in fluid-filled pipes with and without leakage have great potential in leakage detection in pipeline systems and can detect very small leaks of 1 mm diameter. Second, the measured noise-contaminated acoustic wave propagation in a fluid-filled pipe can be successfully de-noised using the SWT method in order to clearly identify and locate leakage as little as 5 mm diameter in a pipe. Third, AFEA of a fluid-filled pipe can be achieved with the simulation of only the fluid content of the pipe and without the inclusion of the pipe in the model. This eliminates contact interaction of the solid pipe walls and the fluid, and as a consequence reduces computational time and resources. Fourth, the relationship of the ratio of the leakage diameter to the ratio of the first and second secondary wave amplitudes caused by the leakage can be represented by a second-order polynomial function. Fifth, the identification of leakage in a pipe is intuitive from mere comparison of the acoustic waveforms of an intact pipe with that of a pipe with a leakage.

Originality/value

The research work is a novelty and was developed from the scratch. The AFEA of acoustic wave propagation and acoustic wave reflectometry in a static fluid-filled pipe, and the SWT method have been used for the first time to detect, locate and estimate the size of a leakage in a fluid-filled pipe.

Details

International Journal of Structural Integrity, vol. 8 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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Article

Thomas D.A. Jones, David Flynn, Marc P.Y. Desmulliez, Dennis Price, Matthew Beadel, Nadia Strusevich, Mayur Patel, Chris Bailey and Suzanne Costello

This study aims to understand the influence of megasonic (MS)-assisted agitation on printed circuit boards (PCBs) electroplated using copper (Cu) electrolyte solutions to…

Abstract

Purpose

This study aims to understand the influence of megasonic (MS)-assisted agitation on printed circuit boards (PCBs) electroplated using copper (Cu) electrolyte solutions to improve plating efficiencies through enhanced ion transportation.

Design/methodology/approach

The impact of MS-assisted agitation on topographical properties of the electroplated surfaces was studied through a design of experiments by measuring surface roughness, which is characterised by values of the parameter Ra as measured by white light phase shifting interferometry and high-resolution scanning electron microscopy.

Findings

An increase in Ra from 400 to 760 nm after plating was recorded for an increase in acoustic power from 45 to 450 W. Roughening increased because of micro-bubble cavitation energy and was supported through direct imaging of the cavitation. Current thieving effect by the MS transducer induced low currents, leading to large Cu grain frosting and reduction in the board quality. Current thieving was negated in plating trials through specific placement of transducer. Wavy electroplated surfaces, due to surface acoustic waves, were also observed to reduce the uniformity of the deposit.

Research limitations/implications

The formation of unstable transient cavitation and variation of the topology of the Cu surface are unwanted phenomena. Further plating studies using MS agitation are needed, along with fundamental simulations, to determine how the effects can be reduced or prevented.

Practical implications

This study can help identify manufacturing settings required for high-quality MS-assisted plating and promote areas for further investigation, leading to the development of an MS plating manufacturing technique.

Originality/value

This study quantifies the topographical changes to a PCB surface in response to MS agitation and evidence for deposited Cu artefacts due to acoustic effects.

Details

Circuit World, vol. 42 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article

Arup Guha Niyogi, M.K. Laha and P.K. Sinha

The structural acoustic problem, wherein an acoustic domain is confined within a partly flexible laminated composite enclosure is presented. From the finite element free…

Abstract

The structural acoustic problem, wherein an acoustic domain is confined within a partly flexible laminated composite enclosure is presented. From the finite element free vibration analysis of the laminated folded plate structure a mobility relation is derived between the normal velocity of the structure and normal pressure on the structure. A boundary element solver for the Helmholtz equation with quadratic isoparametric elements is developed using pressure‐velocity formulation. Velocity is known over certain parts of the boundary, the rest being the interactive boundary, where the mobility relation correlates nodal pressures and velocities, neither explicitly known. The pressure boundary values are solved from the boundary element and the mobility relations, while the nodal particle velocities and domain pressures are computed at desired points thereafter. New results presented here reveal the effects of the variation in magnitude of structural damping, fiber angles and the thickness of walls.

Details

Aircraft Engineering and Aerospace Technology, vol. 72 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

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Article

Zhicheng He, Guangyao Li, Guiyong Zhang, Gui-Rong Liu, Yuantong Gu and Eric Li

In this work, an SFEM is proposed for solving acoustic problems by redistributing the entries in the mass matrix to “tune” the balance between “stiffness” and “mass” of…

Abstract

Purpose

In this work, an SFEM is proposed for solving acoustic problems by redistributing the entries in the mass matrix to “tune” the balance between “stiffness” and “mass” of discrete equation systems, aiming to minimize the dispersion error. The paper aims to discuss this issue.

Design/methodology/approach

This is done by simply shifting the four integration points’ locations when computing the entries of the mass matrix in the scheme of SFEM, while ensuring the mass conservation. The proposed method is devised for bilinear quadratic elements.

Findings

The balance between “stiffness” and “mass” of discrete equation systems is critically important in simulating wave propagation problems such as acoustics. A formula is also derived for possibly the best mass redistribution in terms of minimizing dispersion error reduction. Both theoretical and numerical examples demonstrate that the present method possesses distinct advantages compared with the conventional SFEM using the same quadrilateral mesh.

Originality/value

After introducing the mass-redistribution technique, the magnitude of the leading relative dispersion error (the quadratic term) of MR-SFEM is bounded by (5/8), which is much smaller than that of original SFEM models with traditional mass matrix (13/4) and consistence mass matrix (2). Owing to properly turning the balancing between stiffness and mass, the MR-SFEM achieves higher accuracy and much better natural eigenfrequencies prediction than the original SFEM does.

Details

Engineering Computations, vol. 32 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

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Article

Jiří Běhal and Pavel Zděnek

There are structural elements on the aircraft that may be exposed to high-intensity sound levels. One of them is an air inlet duct of the jet engine. To prepare data for…

Abstract

Purpose

There are structural elements on the aircraft that may be exposed to high-intensity sound levels. One of them is an air inlet duct of the jet engine. To prepare data for the air duct damage tolerance analysis, flat panels were tested under acoustic loading. The paper aims to discuss this issue.

Design/methodology/approach

The acoustic fatigue test equipment for grazing wave’s incidence was designed based on the FE analyses. Flat composite panels were designed and manufactured using the Hexply 8552/AGP193-PW prepreg with the simulation of production imperfections or operational damage. The dynamic behaviour of panels has been tested using three regimes of acoustic loading: white noise spectrum, engine noise spectrum and discrete harmonic frequencies. The panel deflection was monitored along its longitudinal axis, and the ultrasonic NDT instruments were used for the monitoring of relevant delamination increments. The FE model of the panel was created in Abaqus to study panel dynamic characteristics.

Findings

No delamination progress was observed by NDT testing even if dynamic characteristics, especially modal frequency, of the panel changed during the fatigue test. Rayleigh damping coefficients were evaluated for their use in FE models. Significant differences were found between the measured and computed panel deflection curves near the edge of the panel.

Originality/value

The research results underscored the signification of the FE model boundary conditions and the element type selections when the panel works like a membrane rather than a plate because of their low bending stiffness.

Details

International Journal of Structural Integrity, vol. 11 no. 5
Type: Research Article
ISSN: 1757-9864

Keywords

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