A Study on the Acoustic Characteristics and Absorption Performance Improvement Method of Double Layered Sound Absorption System Using High Density Polyester Absorbing Materials

In industrial and architectural applications, noise can be controlled using sound-absorbing materials. Natural materials are now gaining importance in the noise control engineering as they have advantages like low cost, eco-friendly, easy to produce, etc. Jute is one of such natural materials, which can be used as a sound-absorbing material. Micro-perforated panels along with three different types of jute felts are used in a multilayer sound absorber configuration to improve its sound absorption. The sound absorption performance of these multilayer sound absorbers is evaluated by using the transfer matrix method and experimental method. Dependence of sound absorption performance on the placement of micro-perforated panels in a multilayer sound absorber is also studied. It is observed that the sound absorption performance depends on the position of micro-perforated panels in a multilayer sound absorber.

Download Full-text

Acoustic Enhancement of a Modern Church

Buildings ◽

10.3390/buildings9040083 ◽

2019 ◽

Vol 9 (4) ◽

pp. 83 ◽

Cited By ~ 2

Author(s):

Gino Iannace ◽

Umberto Berardi ◽

Filippo De Rossi ◽

Salvatore Mazza ◽

Amelia Trematerra ◽

...

Keyword(s):

Sound Absorption ◽

Speech Comprehension ◽

Reverberation Time ◽

New Materials ◽

Acoustic Characteristics ◽

Hard Materials ◽

Absorbing Materials ◽

Improvement Interventions ◽

The 1960S ◽

Three Phases

This paper presents the study of the intervention for the acoustic correction of a modern church. The investigated church was built in the 1960s, with a brutalist style and with a squared plan. The hard materials, including a marble floor and hard plastered walls, were responsible for its reverberation time of over 5 s, resulting in poor speech comprehension. As common in worship spaces, the acoustic improvement interventions were challenged by the denial of covering the walls and the vault with conventional sound-absorbing materials due to aesthetic and architectural reasons. In order to carry out an adequate acoustic correction, while involving minimal interventions, the possibility of using light sound absorbing ceiling sheets was analyzed. The study is divided into three phases: Firstly, the acoustic characteristics of the current building were measured; then, new materials for adequate sound absorption were studied; finally, acoustic simulations were used to evaluate the effects on the acoustic characteristics for different intervention scenarios. The final room was able to shorten its reverberation time to about 2.0 s.

Download Full-text

Sound-Absorption Properties of Materials Made of Esparto Grass Fibers

Sustainability ◽

10.3390/su12145533 ◽

2020 ◽

Vol 12 (14) ◽

pp. 5533 ◽

Cited By ~ 4

Author(s):

Jorge P. Arenas ◽

Romina del Rey ◽

Jesús Alba ◽

Roberto Oltra

Keyword(s):

Sound Absorption ◽

Natural Fibers ◽

Normal Incidence ◽

Absorbing Materials ◽

Absorbing Material ◽

Absorption Performance ◽

Sustainable Materials ◽

Reasonable Prediction ◽

Best Fit

Research on sound-absorbing materials made of natural fibers is an emerging area in sustainable materials. In this communication, the use of raw esparto grass as an environmentally friendly sound-absorbing material is explored. Measurements of the normal-incidence sound-absorption coefficient and airflow resistivity of three different types of esparto from different countries are presented. In addition, the best-fit coefficients for reasonable prediction of the sound-absorption performance by means of simple empirical formulae are reported. These formulae require only knowledge of the airflow resistivity of the fibrous material. The results presented in this paper are an addition to the characterization of available natural fibers to be used as alternatives to synthetic ones in the manufacturing of sound-absorbing materials.

Download Full-text

Development of Folded Expanded Metal Mesh with Sound Absorption Performance

Applied Sciences ◽

10.3390/app11157021 ◽

2021 ◽

Vol 11 (15) ◽

pp. 7021

Author(s):

Jui-Yen Lin ◽

Yaw-Shyan Tsay ◽

Pin-Chieh Tseng

Keyword(s):

Sound Absorption ◽

Gypsum Board ◽

Metal Mesh ◽

Expanded Metal ◽

Common Location ◽

Absorbing Materials ◽

Absorption Performance ◽

Speech Clarity ◽

Rock Wool

Reverberation time (RT) is an important factor affecting the quality of indoor acoustics. Using sound-absorbing materials is one method for quickly and effectively controlling RT, and installation in the ceiling is a common location. Sound-absorbing ceilings come in many forms, with light steel joist ceilings commonly used in office spaces, classrooms, and discussion rooms. Light steel joist ceilings are often matched with sound-absorbing materials such as gypsum board, mineral fiberboard, rock wool, and coated glass wool, but such materials may have durability and exfoliation problems. Therefore, considering performance and health, in this research, we aimed to design an expanded metal mesh (EMM) structure specimen for sound-absorption material, namely folded expanded metal mesh (FEMM). The results show that the FEMM can significantly improve the sound-absorption performance of the expanded metal mesh. Theof single panel is 0.05–0.35, and theof FEMM is 0.65–0.85. On the other hand, the sound-absorption performance of the full frequency band has been significantly improved. Furthermore, the field validation result shows that RT decreased from 1.05–0.56 s at 500 Hz, meanwhile, the sound pressure level (SPL) is still evenly distributed, and speech clarity (C50) is increased by 5.6–6.5.

Download Full-text

SOUND ABSORPTION OF SOUND SUPRESSING LIGHTWEIGHT STRUCTURED PANELS

Akustika ◽

10.36336/akustika20193440 ◽

2019 ◽

Vol 34 ◽

pp. 40-43

Author(s):

Valery Murzinov ◽

Pavel Murzinov ◽

Sergey Popov ◽

Julia Taratinova

Keyword(s):

Absorption Coefficient ◽

Surface Density ◽

Sound Absorption ◽

Sound Absorption Coefficient ◽

Sound Insulation ◽

Acoustic Characteristics ◽

Absorbing Materials

Description of the effective soundproofing panel is presented. For this panel, the ratio of acoustic characteristics and surface density exceeds many modern sound insulation and sound absorbing materials and structures. This article is devoted to modeling the sound absorption coefficient of the soundproof panel. The article presents formulas for determining the coefficient of sound absorption. Construction of a sound suppressed lightweight structured panel (SSLSP) developed by the authors is shown. Comparison of the effectiveness of the SSLSP panel and modern sound-proof materials is shown.

Download Full-text

Influence of Sugar Palm Ash Fraction and Resonator Configuration on Acoustic Absorption Performance of Expose Brick

INDONESIAN JOURNAL OF APPLIED PHYSICS ◽

10.13057/ijap.v4i01.1160 ◽

2016 ◽

Vol 4 (01) ◽

pp. 19

Author(s):

Zulfa Kamila R ◽

Iwan Yahya ◽

Utari U

Keyword(s):

Performance Improvement ◽

Performance Optimization ◽

Sound Absorption ◽

Low Frequency ◽

Helmholtz Resonator ◽

Raw Material ◽

Frequency Range ◽

Helmholtz Resonators ◽

Resonator Structure ◽

Absorption Performance

Sound absorption performance optimization of expose brick has been conducted in associated with the fraction of sugar palm ash in its raw material and configuration of Helmholtz resonators inside the brick structure. The testing was conducted experimentally refer to ASTM E-1050-98 standard procedure. In this case there are three variations sugar palm ash fractions of 0%, 5%, and 10%, as well as two array resonator configurations. The results showed that the brick with fraction of 10% sugar palm ash has the best sound absorption performance. As for the configuration of array identical Helmholtz resonator giving better performance improvement at low frequency span than complex resonator structure with coupled cavity where the best performance occur on(376-488) Hz frequency range with the absorption coefficient α of 0.54.

Download Full-text

Fabrication of Millable Polyurethane Elastomer/Eucommia Ulmoides Rubber Composites with Superior Sound Absorption Performance

Materials ◽

10.3390/ma14237487 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7487

Author(s):

Yuhang Dong ◽

Dexian Yin ◽

Linhui Deng ◽

Renwei Cao ◽

Shikai Hu ◽

...

Keyword(s):

Sound Absorption ◽

Polyurethane Elastomer ◽

Eucommia Ulmoides ◽

Frequency Range ◽

Rubber Composites ◽

Absorption Properties ◽

Absorbing Materials ◽

Absorption Performance ◽

Blending Process ◽

Physical Blending

Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. The microstructure surface of various MPU/EUG composites became rough and cracked by the gradual incorporation of EUG, resulting in a deteriorated compatibility between EUG and MPU. With the increase of EUG content, the storage modulus (E’) of various MPU/EUG composites increased in a temperature range of −50 °C to 40 °C and their loss factor (tanδ) decreased significantly, including a reduction of the tanδ of MPU/EUG (70/30) composites from 0.79 to 0.64. Specifically, the addition of EUG sharply improved the sound absorption performances of various MPU/EUG composites in a frequency range of 4.5 kHz–8 kHz. Compared with that of pure MPU, the sound absorption coefficient of the MPU/EUG (70/30) composite increased 52.2% at a pressure of 0.1 MPa and 16.8% at a pressure of 4 MPa, indicating its outstanding sound absorption properties.

Download Full-text

Sound absorption performance of flexible polyurethane/silicon dioxide perforated coating composites

Textile Research Journal ◽

10.1177/00405175211015516 ◽

2021 ◽

pp. 004051752110155

Author(s):

Min Peng ◽

Xiaoming Zhao ◽

Weibin Li

Keyword(s):

Silicon Dioxide ◽

Sound Absorption ◽

Woven Fabric ◽

Perforation Rate ◽

Cavity Depth ◽

Resonant Frequencies ◽

The Matrix ◽

Absorption Performance ◽

Traditional Sense ◽

Flexible Polyurethane

Perforated materials in the traditional sense are rigid, usually dense, costly and inflexible. For this study, polyester/cotton blended woven fabric as the base fabric, nano-SiO2 (silicon dioxide) as the functional particles and PU (polyurethane) as the matrix were selected. Accordingly, flexible PU/SiO2 perforated coating composites with different process parameters were developed. The inﬂuence of the nano-SiO2 content, perforation diameter, perforation rate, number of fiber felt layers and cavity depth on the sound absorption coefficient were investigated. The resonant frequencies of materials with different cavity depths were evaluated by both theoretical calculation and experimental method. It was found that the flexible perforated composite has good sound absorption and mechanical properties, and has great potential for applications requiring soft and lightweight sound absorption materials.

Download Full-text

Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽

10.3390/ma13051091 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1091 ◽

Cited By ~ 1

Author(s):

Dengke Li ◽

Daoqing Chang ◽

Bilong Liu

Keyword(s):

Boundary Condition ◽

Porous Material ◽

Porous Materials ◽

Sound Absorption ◽

Azimuthal Angle ◽

Octave Band ◽

Frequency Range ◽

Absorption Coefficients ◽

Perforated Plates ◽

Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

Download Full-text

Application of transparent microperforated panel to acrylic partitions for desktop use: A case study by prototyping

10.14324/111.444/000076.v2 ◽

2021 ◽

Author(s):

Kimihiro Sakagami ◽

Midori Kusaka ◽

Takeshi Okuzono ◽

Shigeyuki Kido ◽

Daichi Yamaguchi

Keyword(s):

Adverse Effect ◽

Sound Absorption ◽

Acoustic Environment ◽

Actual Use ◽

Acrylic Sheet ◽

Absorption Performance ◽

The Subject ◽

Droplet Penetration ◽

Absorption Characteristics

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to a possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.

Download Full-text