Empirical study on the correlation between measurement methods under diffuse and direct sound field conditions for determining sound absorption and airborne sound insulation properties of noise barriers

2021 ◽  
Vol 263 (3) ◽  
pp. 3350-3361
Author(s):  
Andreas Fuchs ◽  
Reinhard Wehr ◽  
Marco Conter
Keyword(s):  
Empirical Study ◽  
Sound Absorption ◽  
Sound Field ◽  
Research Programme ◽  
Measurement Methods ◽  
Field Conditions ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Noise Barriers ◽  
Airborne Sound

In the frame of the SOPRANOISE project (funded by CEDR in the Transnational Road Research Programme 2018) the database of the European noise barrier market developed during the QUIESST project was updated with newly acquired data. This database gives the opportunity for an empirical study on the correlation between the different measurement methods for the acoustic properties of noise barriers (according to the EN 1793 series) to further investigate the interrelationships between these methods by using single-number ratings and third-octave band data. First a correlation of the measurement methods for sound absorption under diffuse field conditions (EN 1793-1) and sound reflection under direct sound field conditions (EN 1793-5) is presented. Secondly, a correlation of the measurement methods for airborne sound insulation under diffuse field conditions (EN 1793-2) and airborne sound insulation under direct sound field conditions (EN 1793-6) is shown. While for airborne sound insulation a distinct correlation is found due to the wide data range, for sound absorption no robust correlation can be found.

SOPRANOISE - update and analysis of noise barrier database including new current results

2021 ◽  
Vol 263 (3) ◽  
pp. 3073-3084
Author(s):  
Marco Conter ◽  
Andreas Fuchs ◽  
Paul Reiter
Keyword(s):  
Sound Field ◽  
Research Programme ◽  
Field Conditions ◽  
Background Information ◽  
Noise Barriers ◽  
Field Methods ◽  
Acoustic Performance ◽  
Measurement Results ◽  
Noise Barrier ◽  
Single Number

In the frame of the SOPRANOISE project (funded by CEDR in the Transnational Road Research Programme 2018) work package 2 focused first on providing theoretical and practical background information on measurement of the acoustic performance of noise barriers due to a state-of-the-art regarding correlations and possible trends between diffuse (EN 1793-1, EN 1793-2) and direct sound field methods (EN 1793-5, EN 1793-6). After that, the objective of this research was to extend and update the database of the European noise barrier market developed during the QUIESST project, including more detailed analyses on single-number ratings as well as third-octave band measurement results. The data collected and the analysis performed show relevant facts and figures about acoustic performances of noise barriers measured under diffuse and direct sound field conditions, together with a better understanding of the respective significance, similarities and differences of these standardized methods, improving data analysis and correlations between these methods. This paper gives a general overview of the data collected, summarising the main results of the statistical analyses performed. Overall results and comparisons between results of measurements performed under diffuse and under direct sound field conditions are shown. Finally, conclusions and possible outlook of the research are presented.

scholarly journals A Novel Acoustic Sandwich Panel Based on Sheep Wool

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 148
Author(s):  
Daniela-Roxana Tămaş-Gavrea ◽  
Tünde-Orsolya Dénes ◽  
Raluca Iştoan ◽  
Ancuţa Elena Tiuc ◽  
Daniela Lucia Manea ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Sandwich Panel ◽  
Bending Strength ◽  
Hydrated Lime ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Partition Wall ◽  
Airborne Sound ◽  
Composite Face ◽  
Sheep Wool

The aim of this paper is to propose a novel sandwich panel, which would be suitable for sound absorption and airborne sound insulation, used as applied cladding or independent lightweight partition wall. As far as the authors are concerned, this is the first sheep wool-based sandwich panel using only natural materials. The structure was prepared using hydrated lime-based composite face sheets and a sheep wool-based core. Several parameters of the sandwich panel were determined, including sound absorption coefficient, airborne sound insulation, thermal conductivity, thermal resistance, compressive strength, and bending strength, respectively. The results indicate that the maximum sound absorption value of 0.903 was obtained at the frequency of 524 Hz in the case of the unperforated sample, 0.822 at 536 Hz in the case of the sample with 10% perforations, 0.780 at 3036 Hz in the case of the sample with 20% perforations, and 0.853 at 3200 Hz in the case of the sample with 30% perforations. The registered airborne sound insulation index of the panel was 38 dB. Based on the obtained data, it can be concluded that the studied panel recorded comparable values with other synthetic noise control solutions, which are suitable as applied cladding or an independent lightweight partition wall, with good acoustic properties.

scholarly journals Factors Affecting Acoustic Properties of Natural-Fiber-Based Materials and Composites: A Review

Textiles ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 55-85
Author(s):  
Tufail Hassan ◽  
Hafsa Jamshaid ◽  
Rajesh Mishra ◽  
Muhammad Qamar Khan ◽  
Michal Petru ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Type ◽  
Alkali Treatment ◽  
Acoustic Properties ◽  
Synthetic Fiber ◽  
Sound Insulation ◽  
Factors Affecting ◽  
Wide Range

Recently, very rapid growth has been observed in the innovations and use of natural-fiber-based materials and composites for acoustic applications due to their environmentally friendly nature, low cost, and good acoustic absorption capability. However, there are still challenges for researchers to improve the mechanical and acoustic properties of natural fiber composites. In contrast, synthetic fiber-based composites have good mechanical properties and can be used in a wide range of structural and automotive applications. This review aims to provide a short overview of the different factors that affect the acoustic properties of natural-fiber-based materials and composites. The various factors that influence acoustic performance are fiber type, fineness, length, orientation, density, volume fraction in the composite, thickness, level of compression, and design. The details of various factors affecting the acoustic behavior of the fiber-based composites are described. Natural-fiber-based composites exhibit relatively good sound absorption capability due to their porous structure. Surface modification by alkali treatment can enhance the sound absorption performance. These materials can be used in buildings and interiors for efficient sound insulation.

Considerations for the Reduction of Noise in Ship Installations of Gas Turbines

1960 ◽  
Vol 82 (3) ◽  
pp. 205-214
Author(s):  
Edward M. Herrmann
Keyword(s):  
Noise Reduction ◽  
Gas Turbines ◽  
Sound Absorption ◽  
Sound Insulation ◽  
Specific Information ◽  
Airborne Sound

General noise reduction considerations for shipboard installation of gas turbines are discussed. Specific information relating to sound-absorption materials, duct treatments, structureborne sound isolation, and airborne sound insulation is graphically presented.

scholarly journals Sound absorbing and insulating properties of natural fiber hybrid composites using sugarcane bagasse and bamboo charcoal

2021 ◽  
Vol 16 ◽  
pp. 155892502110448
Author(s):  
Santhanam Sakthivel ◽  
Selvaraj Senthil Kumar ◽  
Eshetu Solomon ◽  
Gedamnesh Getahun ◽  
Yohaness Admassu ◽  
...  
Keyword(s):  
Composite Materials ◽  
Physical Properties ◽  
Sugarcane Bagasse ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Bamboo Charcoal ◽  
Green Composite

This research paper reports a study on thermal and sound insulation samples developed from sugarcane bagasse and bamboo charcoal for automotive industry applications. The sugarcane bagasse and bamboo charcoal fiber is a potential source of raw material that can be considered for thermal and sound insulation applications. Natural fibers are commonly used in diverse applications and one of the most important applications is sound absorption. Natural fiber hybrid composite currently is in greater demand in industries because of their advantages such as low cost, biodegradability, acceptable physical properties, and so on. Eco-friendly sound-absorbing composite materials have been developed using bamboo charcoal and sugarcane bagasse fibers. From these fibers five types of natural fiber green composite were developed using the compression bonding technique. The natural composite noise control performance contributes to its wider adoption as sound absorbers. The sound absorption coefficient was measured according to ASTM E 1050 by the Impedance tube method. The physical properties of natural fiber composites such as thickness, density, porosity, air permeability, and thermal conductivity were analyzed for all samples in accordance with ASTM Standard. The result exposed that natural fiber green composite were absorbing the sound resistance of more than 70% and the natural fibers composites provide the best acoustic absorption properties, these composite materials have adequate moisture resistance at high humidity conditions without affecting the insulation and acoustic properties.

scholarly journals Acoustic Properties of 316L Stainless Steel Lattice Structures Fabricated via Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 111 ◽  
Author(s):  
Xiaojing Sun ◽  
Fengchun Jiang ◽  
Jiandong Wang
Keyword(s):  
Stainless Steel ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Sound Absorption ◽  
316L Stainless Steel ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Frequency Range ◽  
Laser Melting ◽  
The Difference

A bulk specimen and two different lattice sandwich structures composed of 316L stainless steel were fabricated via selective laser melting. This study analysed the acoustic properties, including sound insulation and sound absorption, of the three kinds of structures, which were produced via selective laser melting under the same process parameters. The results showed that the difference in the unit structures, rather than microstructural difference, was the main reason for the difference in acoustic properties between the samples. Under the same process parameters, the microstructure of the different structures had the same cell structure. However, the sound absorption properties of the lattice sandwich structures were better than those of the bulk sample in the measured frequency range of 1–6.3 kHz. The lattice sandwich structure with 2.5 × 2.5 × 2.5 mm3 unit structures exhibited excellent sound insulation properties in the frequency range of 1–5 kHz.

Influence of the Installation Lines to the Acoustic Properties of Dividing Wall

2015 ◽  
Vol 752-753 ◽  
pp. 728-732
Author(s):  
Jiří Winkler ◽  
Darja Kubeckova ◽  
Lucie Kucerova ◽  
Nada Zdrazilova
Keyword(s):  
Structural Damage ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Structural Systems ◽  
Technical Equipment ◽  
Noise Propagation ◽  
Airborne Sound ◽  
Experimental Structure ◽  
Hollow Bricks

This article presents the results of long-term research of airborne sound insulation of a dividing wall. Specifically it shows how strong effect on the acoustic properties of the dividing walls has the line installation of technical equipment of building. The experimental structure was built from shaped hollow bricks where the influence of structural damage is in terms of the noise propagation essential. This type of structure was selected because it is one of the most commonly used structural systems and the acoustic properties are still neglected aspect.

Research and Application of Building Enclosing Structure Used in Equipment Noise Control

2013 ◽  
Vol 423-426 ◽  
pp. 1272-1278
Author(s):  
Nan Xu
Keyword(s):  
Porous Material ◽  
Sound Absorption ◽  
Noise Control ◽  
Building Envelope ◽  
Sound Insulation ◽  
Hard Material ◽  
Noise Elimination ◽  
Control Engineering ◽  
Airborne Sound ◽  
Properties Of Materials

Porous material has a function of sound absorption, dense hard material can prevent the spread of airborne sound. The building envelope which is made up of different properties of materials, with good effects on sound insulation, sound absorption and noise elimination, can be widely used in noise control engineering.

An Alternative Method for Measurement of Airborne Sound Insulation

2001 ◽  
Vol 8 (1) ◽  
pp. 57-74 ◽  
Author(s):  
Karl-Ola Lundberg
Keyword(s):  
Transmission Coefficient ◽  
Impulse Response ◽  
Physical System ◽  
Sound Absorption ◽  
Sound Insulation ◽  
Power Balance ◽  
Propagation Time ◽  
Time Varying ◽  
Airborne Sound ◽  
Absorption Area

A method for determination of the transmission coefficient from Complex Modulation Transfer Functions CMTF:s based on measured impulse-responses is shown. In the method a separate measurement of the equivalent sound absorption area is not needed in contrast to in the standardised measurement. By averaging over a number of estimates of the impulse-response the influence of background noise can be reduced substantially, implying that low-power sources can be used. A model for the power balance in the receiving room with time-varying power is considered. In the model the quotient of the receiving room intensity and the source room intensity has one pole, which is proportional to the equivalent sound absorption area in the receiving room, and a gain, proportional to the transmission coefficient. In the physical system the power can be time-varied by letting the system excitation signal consist of random noise modulated with a deterministic time-varying function. However, since the ensemble average of the squared response is proportional to the squared impulse-response convolved with the squared modulating function, random excitation is avoided and replaced by impulse-response measurements. The quotient of intensities in the model is in the physical system a quotient of CMTF:s. Experiments are carried out in an airborne sound insulation laboratory. For comparison, standardised measurements are also carried out. It is found that the presented method gives as result comparatively small transmission coefficients, though the relative differences are small. By refining the power balance model by introducing an energy propagation time delay, and selecting an appropriate delay, the differences were diminished.

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