Article
Materials Science, Multidisciplinary
Faisal Rafique, Jiu Hui Wu, Syed Murawat Abbas Naqvi, Muhammad Waqas, Chong Rui Liu
Summary: Low-frequency wideband noise reduction has been a significant problem in recent years. This paper proposes a composite acoustic structure consisting of parallel-arranged inhomogeneous micro-perforated panel (iMPP) and spider-web-designed cavities. Different spider-web shapes, including circular, octagonal, and square, are studied. By controlling various design parameters, such as inhomogeneous patterns and perforation ratio, a broader multipeak low-frequency sound-absorbing performance equivalent to different resonant frequencies can be achieved. Theoretical analysis and finite-element method (FEM) simulation are used to predict the sound absorption coefficient of the new design, which is then verified experimentally. The new composite structure, composed of inhomogeneous MPP and spider-web-designed cavities, achieves a highly effective low-frequency broadband sound absorption with an average absorption coefficient of over 90% within the bandgap of 230 Hz to 470 Hz.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART L-JOURNAL OF MATERIALS-DESIGN AND APPLICATIONS
(2023)
Article
Engineering, Mechanical
Weiping Yang, Yatsze Choy, Ying Li
Summary: In this study, the sound absorption performance of a wavy micro-perforated panel absorber (WMPPA) is investigated. The WMPPA exhibits promising potential for the control of low-frequency and broadband noise, with improved sound absorption performance at lower frequencies and additional absorption peaks in the middle to high-frequency range. The study validates the proposed model and uncovers the acoustical properties and performance enhancements of the WMPPA.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Acoustics
Faisal Rafique, Jiu Hui Wu, Chong Rui Liu, Fuyin Ma
Summary: In this paper, a composite structure consisting of an inhomogeneous micro-perforated panel (IMPP) backed with J-shaped cavities of different depths is proposed for low-frequency sound absorption. The results show that increasing the length and volume of the back cavities, as well as the thickness of the IMPP, enhances the low-frequency sound absorption performance. The structure was further verified through theoretical, simulation, and experimental studies, with good agreement among the three.
ACOUSTICS AUSTRALIA
(2022)
Article
Engineering, Mechanical
Tan Wei Hong, Faridah Wahab, Lee Jia Jian, Siti Hajar Ishak
Summary: This study presents the sound absorption performance of bio-composite micro-perforated panels (BC-MPP) made from composite polypropylene filled with rice husk (PP/RH) and coconut coir (PP/CC). The sound absorption coefficient (SAC) of BC-MPP was obtained using the impedance tube two-microphone method, and the investigation focused on fillers, filler compositions, perforation ratio, and air gap size. It was found that BC-MPP PP/RH had a higher SAC value than BC-MPP PP/CC. Additionally, the SAC peak shifted to lower frequency spectrum with an increase in filler content, perforation distance, and air gap size. The simulated SAC values also showed good agreement with experimental results.
JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Xiang Liu, Chunqi Wang, Yumin Zhang, Lixi Huang
Summary: An investigation into a smart micro-perforated panel aims to enhance the sound absorption performance of MPP absorbers at low frequencies, utilizing a combination of mechanical damping, electrical shunt damping, and Helmholtz resonance. Different multimode shunt design methods are explored to intensify panel vibration and improve sound absorption, with absorption peaks induced by electromechanical coupling found at frequencies lower than the MPP's Helmholtz resonance frequency.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Acoustics
Mohamed Shafeer P.p, Jeyaraj Pitchaimani, Mrityunjay Doddamani
Summary: In recent years, noise pollution has been recognized as a significant environmental issue, and there has been considerable attention on using sustainable materials as sound-absorbing building materials. This study focuses on the influence of graded perforations on the acoustic characteristics of a 3D printed bio-degradable thick micro-perforated panel (MPP) made of Poly Lactic Acid. The results show that the overall perforation ratio of the panel is the main factor affecting the sound absorption coefficient, while the perforation gradation and patterning have no significant influence. Additionally, this study proposes an effective perforation ratio approach to predict the sound absorption coefficient of MPPs with graded perforation.
ACOUSTICS AUSTRALIA
(2023)
Article
Engineering, Mechanical
Xiyue Ma, Daniil Yurchenko, Kean Chen, Lei Wang, Yang Liu, Kai Yang
Summary: This paper investigates the performance of a new type of sound-controlled micro-perforated panel absorber, which achieves wide-band perfect low-frequency sound absorption using a point force controlled backing panel. The theoretical model is established and the influence of structure size and point force position on sound absorption performance is explored. Experimental tests are conducted to validate the findings, and the physical mechanisms of active control are analyzed. A simplified error sensing strategy is also constructed. The results show that locating the point force at the center or using a relatively small sized absorber can achieve perfect sound absorption in a wide controllable bandwidth.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Acoustics
Jingfeng Ning, Qian Geng, M. P. Arunkumar, Yueming Li
Summary: A light composite absorber with a micro-perforated sandwich panel filled with thin porous materials is proposed in this study to achieve a wide absorption bandwidth. The theoretical model derived by the transfer matrix method is in good agreement with experimental results, showing better performance compared to other absorbers. The absorption mechanism and the effects of internal components on absorption performance are analyzed in detail.
Article
Acoustics
Chenhao Dong, Zhao Liu, Robert Pierce, Xiaoling Liu, Xiaosu Yi
Summary: A new micro perforated sandwich panel with honeycomb-hierarchical pore structure core is developed in this study. By combining carbonized cotton with hierarchical pore structure and a micro perforated honeycomb core, the sound-absorbing performance of the structure is enhanced without significant weight increase. Experimental results show that the average sound absorption coefficient of the structure can be improved from 0.220 to 0.558 with pure carbonized cotton filling, and further increased to 0.626 with hierarchical pore structure. Additionally, theoretical and finite element models are established with prediction errors of 16.8% and 8.6% respectively.
Article
Engineering, Mechanical
Faisal Rafique, Jiu Hui Wu, Muhammad Waqas, Xu Lushuai, Fuyin Ma
Summary: A new type of absorber consisting of multiple parallel-arranged inhomogeneous microperforated panels (MPPs) is proposed to achieve wideband low-frequency sound absorption. The theoretical study and simulation results show that this absorber can produce a wider absorption bandwidth with a high absorption coefficient in the low-frequency region. Furthermore, the performance of the absorber can be further improved through optimization.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2022)
Article
Acoustics
David Jun, Ondrej Nespesny, Jan Pencik, Zuzana Fisarova, Ales Rubina
Summary: The article focuses on an optimized method for Helmholtz resonators (HR) design in room acoustics. An experiment in a reverberation room was conducted to verify calculation methods for sound absorption coefficient, and the calculation was optimized to better match the measurements.
Article
Engineering, Mechanical
Faridah Wahab, Tan Wei Hong, Mohamad Haziman Mohamad Azhar, Nor Hafizul Hilni Abdul Rahman
Summary: This study investigates the sound absorption properties of a bio-composite microperforated panel (BC-MPP) with a combination of natural fibers and a backed structure. Experimental results show that the introduction of natural fibers significantly improves the sound absorption coefficient and shifts the peak to lower frequencies.
JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Wei He, Xiangjun Peng, Fengxian Xin, Tian Jian Lu
Summary: This study investigates the superior sound absorption performance of ultralight micro-perforated sandwich panels with double-layer hierarchical honeycomb core. Theoretical model predictions and numerical simulations validate the physical mechanisms underlying sound absorption, with systematic parametric study revealing optimal structural parameters for maximizing sound absorption. Viscous dissipation of air inside micro-perforations and around inlet/outlet regions is shown to dominate sound absorption, while the proposed hierarchical construction offers improved load-bearing capacity and significantly enhanced sound absorption across a wide frequency range compared to panels with regular honeycomb core.
JOURNAL OF SANDWICH STRUCTURES & MATERIALS
(2022)
Article
Acoustics
Shanlin Yan, Jinwu Wu, Jie Chen, Yin Xiong, Qibo Mao, Xiang Zhang
Summary: The study investigated the sound absorption performance of micro-perforated plate under different parameters and designed two single-layer honeycomb micro-perforated plate structures using optimization algorithm to achieve broadband sound absorption. Experimental results showed that the depth of the perforations had a significant impact on the sound absorption performance, and using particle swarm optimization algorithm can improve the performance.
Article
Acoustics
Faisal Rafique, Jiu Hui Wu, Syed Murawat Abbas Naqvi, Fuyin Ma
Summary: A single layer of four parallel-arranged inhomogeneous microperforated panels (iMPP) absorber is proposed to achieve low-frequency sound absorption and wider frequency bandwidth. The absorption coefficient and bandwidth can be tuned by adjusting various parameters, and designing different sub-MPP configurations can produce wider absorption bandwidth in the low-frequency region. The enhanced iMPP absorber shows great potential in acoustics and noise control applications due to its exceptional absorption performance in the low-frequency range.
ACOUSTICS AUSTRALIA
(2022)
Article
Acoustics
Ali Mosa, A. Putra, R. Ramlan, Al-Ameri Esraa
Article
Materials Science, Textiles
Vignesh Sekar, Se Yong Eh Noum, Sivakumar Sivanesan, Azma Putra, Desmond Daniel Chin Vui Sheng, Dg Hafizah Kassim
Summary: Additive manufacturing (AM) of Natural Fiber-Reinforced Composites through Fused Deposition Modeling is being actively researched, with the ability to control sound absorption performance by varying thickness and infill density of the acoustic panel. The study found that the thin panel with back air gap absorbed sound in the mid-frequency range resembling a Helmholtz resonator, while the absorption performance of the thick panel was controlled by infill density. The customization of acoustic absorption for panels made from biodegradable materials by AM is achievable.
JOURNAL OF NATURAL FIBERS
(2022)
Article
Acoustics
Debelo Dugasa Abdi, Mohammadreza Monazzam, Ebrahim Taban, Azma Putra, Farideh Golbabaei, Monireh Khadem
Summary: This paper presents the sound absorption performance of natural fiber composites developed from chrome shave (CS) and coffee silver skin (CSS), showing promising results, especially above 1 kHz in frequency range.
Article
Construction & Building Technology
Geok Wen Leong, Tze Ming Chin, Kim Hung Mo, Zainah Ibrahim, Azma Putra, Muhammad Nur Othman
Summary: The research shows that the combination of crumb rubber and air-entraining agent can effectively reduce the density of cementitious composite and improve its sound absorption performance. The use of CR and AEA together in ULCC production is efficient in reducing density and enhancing acoustic performance.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Acoustics
Muhamad Syafwan Azmi, Rainah Ismail, Azma Putra
Summary: The purpose of this study is to investigate the influence of various size-based design parameters on the performance of lattice structures in vibration isolation applications. Through static and dynamic analyses, the researchers found that the stiffness of the lattice structure was directly related to the unit cell and strut diameter, with smaller unit cell and larger strut diameter leading to higher strength and load-bearing capacity. The dynamic vibration results were consistent with the findings from the static analysis. The study suggests that the proposed design parameters can be used for tuning lattice isolators in specific applications.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Engineering, Multidisciplinary
Al-Ameri Esraa, Azma Putra, Ali I. Mosa, R. M. Dan, Osam H. Attia
Summary: This paper presents an optimized empirical model for calculating the sound absorption coefficient of a single-layer MPP. By analyzing the relationships between MPP parameters and sound absorption performance, it provides a more convenient method for selecting suitable MPP parameters.
INTERNATIONAL JOURNAL OF TECHNOLOGY
(2022)
Article
Materials Science, Textiles
Dg Hafizah Kassim, Azma Putra, Roszaidi Ramlan
Summary: This study presents the sound absorption performance of multi-layer coir and kapok fibers. It is found that adding a 2 mm thick kapok fiber layer in between the coir fiber layers significantly improves the absorption bandwidth.
JOURNAL OF NATURAL FIBERS
(2023)
Article
Construction & Building Technology
Gunawan, Iwan Prasetiyo, Brian Yuliarto, Azma Putra, Irianto
Summary: Woven fabric perforation is beneficial for meeting the microstructure requirement of a micro-perforated panel absorber. The use of minute holes created by woven fabrics allows for the fabrication of high perforation ratio MPP with a diameter of 0.1-0.3 mm. The study discusses the properties of these minute holes and their associated absorption characteristics. Theoretical results and experimental investigations validate the findings, showing that controlling weft yarn density can successfully fabricate minute holes. The woven fabrics can achieve a half-absorption bandwidth of up to 5000 Hz (>3 octaves) with a peak absorption coefficient of over 0.8, and changing hole diameter can affect absorption behavior. The study confirms the applicability of Maa's model for predicting absorption of MPP using woven fabric material.
Article
Construction & Building Technology
Cheryl Yew Shyh-Qi, Nurul Amira Abd Jalil, Nazli Bin Che Din, Chandramouli Pradeepa, Azma Putra, Waqar Azeem
Summary: This study investigates the impact of the chancel and nave on the acoustic performance of churches. Simulations of four churches with different chancel geometries were conducted, and the results show that both chancel availability and geometry significantly affect the acoustics of churches. Chancel availability mainly influences speech intelligibility, while circular chancels have a more positive effect on speech intelligibility compared to polygonal and rectangular chancels.
Article
Materials Science, Paper & Wood
Vignesh Sekar, Azma Putra, Sabarinathan Palaniyappan, Se Yong Eh Noum, Sivakumar Sivanesan, Yu Lih Jiun
Summary: The rapid urbanization and economic expansion have resulted in increased negative consequences of environmental noise pollution. To address this issue, acoustic absorbers with varying infill patterns were 3D printed to absorb sound across a wide range of frequencies. The acoustic absorbers, made of PLA/PHA-WF, were fabricated using FDM technology and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. The results showed that the acoustic absorbers printed with different infill patterns have slight variations in density and allow sound waves to enter and be absorbed at different spectrum levels.
WOOD MATERIAL SCIENCE & ENGINEERING
(2023)
Article
Construction & Building Technology
Azma Putra, Muhammad Nur Othman, Thaynan Oliveira, M'hamed Souli, Dg Hafizah Kassim, Irianto, Safarudin Herawan
Summary: The paper presents the sound absorption coefficient of acoustic absorbers fabricated from natural durian husk fibers. The results show that durian husk fibers can achieve a high absorption coefficient and can be used as effective sound absorbing materials. The optimized parameters for different densities were calculated using a mathematical model.
Article
Acoustics
Vignesh Sekar, Se Yong Eh Noum, Azma Putra, Sivakumar Sivanesan, Kok Chun Chin, Yi San Wong, Dg Hafizah Kassim
Summary: This paper investigates the development and performance of micro-perforated panels (MPP) made of Polylactic Acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fiber (OPEFBF) on the Sound Absorption Coefficient (SAC). The study found that changes in fiber density, air gap, and perforation ratio can shift the peaks of acoustic absorption, affecting the noise reduction effectiveness.
SOUND AND VIBRATION
(2021)
Article
Acoustics
Al Munawir, Azma Putra, Iwan Prasetiyo, Wan Mohd Farid Wan Mohamad, Safarudin Herawan
Summary: This study investigates the application of a corrected SEA model in a non-reverberant acoustic space, where the direct field component dominates the total sound field. The proposed model removes the direct field component in the energy and considers only the remaining power after the loss at first reflection. Measurements showed good agreement between the corrected SEA model and theoretical results in terms of coupling loss factor and damping loss factor.
SOUND AND VIBRATION
(2021)
Article
Construction & Building Technology
Syed Nasir Shah, Kim Hung Mo, Soon Poh Yap, Azma Putra, Muhammad Nur Othman
Summary: The innovative incorporation of CR in cement composite via the preplaced mixing (PM) method has shown better performance in strength and drying shrinkage, with a recommended maximum replacement level of 50% for CR in the cement composite.
ADVANCES IN CONCRETE CONSTRUCTION
(2021)
Article
Acoustics
Cailiang Zhang, Zhihui Lai, Zhisheng Tu, Hanqiu Liu, Yong Chen, Ronghua Zhu
Summary: This paper proposes two single-parameter-adjusting SR models to optimize the output performance of SR systems. The effects of the proposed models on SR output under different parameters and signals are investigated through numerical simulations, and their feasibility is verified through experimental results. The research results are of great significance for guiding the design of tri-stable SR models and the application of SR-based signal processing in the context of big data.
Article
Acoustics
Shaoqiong Yang, Hao Chang, Yanhui Wang, Ming Yang, Tongshuai Sun
Summary: In this study, a suspension system based on phononic crystals is designed for vibration isolation of acoustic loads in underwater gliders. The vibration properties of the phononic crystals and the effects of physical parameters on the underwater attenuation zones are investigated. Vibration tests show that the phononic crystal suspension system has a stable vibration isolation effect in the frequency range of 120-5000 Hz.
Article
Acoustics
Xuebin Zhang, Jun Zhang, Tao Liu, Ning Hu
Summary: This study proposes a tunable metamaterial beam to isolate flexural waves. A genetic algorithm-based size optimization is used to obtain a broad low-frequency bandgap. The tunability of the beam is achieved by attaching different numbers of permanent magnets to change the mass of the resonators. Additionally, ultra-broadband flexural wave attenuation is achieved by forming a gradient metamaterial beam based on the rainbow effect. Numerical and experimental results confirm the good flexural wave attenuation ability of the proposed beam.
Article
Acoustics
Luca Rapino, Francesco Ripamonti, Samanta Dallasta, Simone Baro, Roberto Corradi
Summary: This paper presents a method for simulating tyre/road noise using equivalent monopoles, including the synthesis of monopoles through an inverse problem approach and the use of an ISO 10844 road replica for laboratory testing. The method combines acoustic finite element models and numerical simulations of vehicles, and the results are validated by comparing them with measured data.
Article
Acoustics
Xiaoyan Zhu, Tin Oberman, Francesco Aletta
Summary: This paper explores the definition of acoustical heritage and proposes a multidimensional definition based on interviews with experts and detailed analysis of the data.
Article
Acoustics
Faeez Masurkar, Saurabh Aggarwal, Zi Wen Tham, Lei Zhang, Feng Yang, Fangsen Cui
Summary: This research focuses on estimating the elastic constants of orthotropic laminates using ultrasonic guided waves and inverse machine learning models. The results show that this approach has the potential to accurately predict the elastic constants of a material and reduce computational time.
Article
Acoustics
Feng Xiao, Haiquan Liu, Jia Lu
Summary: Diagnostic methods for cardiovascular disease based on heart sound classification have been widely studied due to their noninvasiveness, low-cost, and high efficiency. However, existing research often faces challenges such as the nonstationarity and complexity of heart sound signals, leading to limited capability of neural networks to extract discriminative features. To address these issues, this study proposes a novel convolutional neural network that combines 1D convolution and 2D convolution, and introduces an attention mechanism to enhance feature extraction capability. The study also explores the advantages and disadvantages of combining deep learning features with manual features, and adopts an evolving fuzzy system for decision-making interpretability.
Article
Acoustics
Hong Xu, Zhengyao He, Qiang Shi, Yushi Wang, Bo Zhang
Summary: This paper presents the development of a directional segmented ring transmitting transducer that can radiate sound waves in any horizontal region. The study focuses on the structure of the segmented ring transducer, its radiation sound field characteristics, and the beam pattern control method based on modal synthesis. The authors propose orthogonal beam pattern functions for adjusting steering angles and establish a three-dimensional finite element model to simulate the transmitting beam patterns. Experimental measurements and tests validate the effectiveness of the proposed transducer, showcasing its ability to steer the beam patterns to different directions.
Article
Acoustics
Jirui Yang, Shefeng Yan, Di Zeng, Gang Tan
Summary: This paper proposes an improved domain adaptation framework, self-supervised learning minimax entropy, to enhance the recognition performance of underwater target recognition models. The experimental results demonstrate that applying domain adaptation methods can effectively improve the recognition accuracy of the models under various marine conditions.
Article
Acoustics
Zonghan Sun, Jie Tian, Yuhang Zheng, Xiaocheng Zhu, Zhaohui Du, Hua Ouyang
Summary: This paper analyzes the noise reduction method of installing a sinusoidal-shaped inlet duct on a cooling fan through theoretical and experimental analysis of the acoustic mode modulation. The study establishes the correlation between the free field noise and acoustic mode of the fan rotor and the unsteady forces on the rotor blade surface. The results show that the sinusoidal-shaped inlet duct achieves greater noise reduction compared to a straight duct, especially at the blade passing frequency and its first harmonic.
Article
Acoustics
Min Li, Rumei Han, Hui Xie, Ruining Zhang, Haochen Guo, Yuan Zhang, Jian Kang
Summary: This study is part of a global collaboration to translate and standardise soundscape research. A reliable questionnaire for soundscape characterisation in Mandarin Chinese was developed and validated. The study found that salient sound sources become the focus of attention for individuals in urban open spaces, and the perception is also influenced by the acoustic characteristics of the soundscape. Certain types of sound sources play a more important role in soundscape perception.
Article
Acoustics
Arezoo Talebzadeh, Dick Botteldooren, Timothy Van Renterghem, Pieter Thomas, Dominique Van de Velde, Patricia De Vriendt, Tara Vander Mynsbrugge, Yuanbo Hou, Paul Devos
Summary: This study proposes a sound selection methodology to enhance the soundscape in nursing homes and reduce BPSD by analyzing sound characteristics and recognition methods. The results highlight the sound characteristics that lead to positive responses, while also pointing out the need for further studies to understand which sounds are most suitable for people with dementia.
Article
Acoustics
Yang Yang, Yongxin Yang, Zhigang Chu
Summary: This paper introduces a grid-free compressive beamforming method compatible with arbitrary linear microphone arrays, and demonstrates the correctness and superiority of the proposed method through examples. Monte Carlo simulations are performed to reveal the effects of source coherence, source separation, noise, and number of snapshots.
Article
Acoustics
Sukru Selim Calik, Ayhan Kucukmanisa, Zeynep Hilal Kilimci
Summary: Computer-Aided Language Learning (CALL) is growing rapidly due to the importance of acquiring proficiency in multiple languages for effective communication. In the field of CALL, the detection of mispronunciations is vital for non-native speakers. This research introduces a novel framework using audio-centric transformer models to detect mispronunciations in Arabic phonemes. The results demonstrate that the UNI-SPEECH transformer model yields notable classification outcomes in Arabic phoneme mispronunciation detection. The comprehensive comparison of these transformer models provides valuable insights and guidance for future investigations in this domain.
Article
Acoustics
Yi-Yang Ni, Fei-Yun Wu, Hui-Zhong Yang, Kunde Yang
Summary: This paper proposes an improved method for compressive sensing by introducing a self training dictionary scheme and a CS reconstruction method based on A*OLS, which enhances the sparse representation performance of propeller signals.
