‫ﺍ‬ ‫ﺫﺏ‬ ‫ﺍﻕ‬ ‫ﺁ‬ 3 ‫ﺩﻭﻭﺭ‬ ‫ﺯﺭﺭﺭﻯ‬-2 ‫ﺭ‬-*1 ‫ﻯﻯﻯﻯﻯ‬ ‫ﻭﻭﻭ‬ Acoustic analysis of a semi-anechoic chamber with intersection layout of rectangular fibrous absorbents

P Nassiri, Monazzam, Zivary Delavar
2018 Journal of Health and Safety at Work   unpublished
‫ﻩ‬ ‫ﺍﻕ‬ ‫ﺍﺩ‬ ‫ﺭ‬ ‫ﺍ‬ ‫ﺭﺕ‬ ‫ﺩﺭ‬ ‫ﻥ‬ ‫ﻁ‬ ‫ﺩﺭ‬ : ‫ﻭ‬ ‫ﺍ‬ ‫ﺍ‬ ‫ﺩﻩ‬ ‫ﺍﺩﻩ‬ ‫ﻭ‬ ‫ﻭ‬ ‫ﻯ‬ ‫ﻩ‬ ‫ﺍ‬ ‫ﻯ‬ ‫ﺫﺏ‬ ‫ﺍﺯ‬ ‫ﺍﻕ‬ ‫ﺭ‬ ‫ﺁ‬ ‫ﻭ‬ ‫ﺍ‬ ‫ﻑ‬ ‫ﺍ‬ .‫ﺍ‬ ‫ﺩﻩ‬ ‫ﺩﺍﺭ‬ ‫ﻭ‬ ‫ﺁﻥ‬ ‫ﺍﺍﻱ‬. ‫ﺭﺕ‬ ‫ﺍ‬ ‫ﻯ‬ ‫ﺫﺏ‬ ‫ﺍﺯ‬ ‫ﺍﺩﻩ‬ ‫ﺯﺁﻭﺍ‬ ‫ﺯﻥ‬ ‫ﺍﻡ‬ ‫ﺍﻥ‬ ‫ﻡ‬ ‫ﺩﺍﻩ‬ ‫ﺍﻕ‬ ‫ﺩﺭ‬ ‫ﺍ‬ ‫ﺩﺭ‬ :‫ﺭ‬ ‫ﺭﻭﺵ‬ .‫ﺩ‬ ‫ﻑ‬ ‫ﺩ‬ ‫ﻭ‬ ‫ﺍ‬ ‫ﺍﺯ‬ ‫ﻭ‬ ‫ﺩﺭ‬ ‫ﺍﻕ‬ ‫ﻭ‬ ‫ﺍﻕ‬ ‫ﺯﻥ‬. ‫ﺍ‬ ‫ﺭﺩ‬ ‫ﻯ‬ ‫ﺫﺏ‬ (AutoCAD, 3Ds Max) ‫ﺍ‬ ‫ﺍﺍﺭﻱ‬ ‫ﻡ‬ ‫ﺍﺯ‬ ‫ﺍ‬ ‫ﺍﺯ‬ ‫ﺍﻕ‬ ‫ﺁﻭﺍ‬ ‫ﺯ‬ ‫ﺯﻥ‬ .‫ﺩ‬ ISO 3382:2000 ‫ﺭﻭﺵ‬ ‫ﺍ‬ ‫ﺍﺯ‬ ‫ﺍﻕ‬ ‫ﺯﺁﻭﺍ‬ ‫ﺍﺯ‬ ‫ﺍﻕ‬ ‫ﻭ‬ ‫ﺡ‬ ‫ﺍﻱ‬ ‫ﻭﻩ‬ ‫ﻝ‬ ‫ﺩﺭ‬ ‫ﻭ‬ () ‫ﺯﺁﻭﺍ‬ ‫ﺯﻥ‬
more » ... ‫ﻭ‬ () ‫ﺯﺁﻭﺍ‬ ‫ﺯﻥ‬ ‫ﺩ‬ .‫ﺩ‬ ‫ﺍﺩﻩ‬ ‫ﺩ‬ 0,3(s)‫ﻩ‬ ISO 3382:2000 ‫ﺭﻭﺵ‬ 250 Hz ‫ﺩﺭ‬ ‫ﺯﺯﺯﺁﻭﺍ‬ ‫ﺯﻥﻥﻥ‬ ‫ﺍﺍﺍﺍﺭ‬ ‫ﺍﺍﺍ‬ ‫ﺍﺯ‬ ::: 253 ‫ﺍﺍﺍ‬ CAD ‫ﺍﺍﺍﺍﺭ‬ ‫ﻡﻡﻡ‬ ...‫ﺩﺩﺩ‬ 247,97 m 2 ‫ﺍﻕﻕﻕ‬ ‫ﻭ‬ 46,32 m 2 ‫ﺍﺍﺍ‬ ‫ﺍﺯ‬ ‫ﺍﻕﻕﻕ‬ ‫ﻭ‬ ‫ﺏﺏ‬ .. ‫ﺯﺩﻩ‬ 50×18‫ﺍﺩﺩﺩﺩ‬ ...‫ﺁ‬ ‫ﺩ‬ @@ 0,07 ‫ﺭﺭﺭﺭﺭ‬ ‫ﺩﺭ‬ ‫ﺯﺯﺯﺁﻭﺍ‬ ‫ﺯﻥﻥﻥ‬ ‫ﻭ‬ 92,64 m 2 ‫ﻭ‬ ‫ﺍ‬ ‫ﺫﺫﺫﺏ‬ ‫ﺍﺯ‬ ‫ﺍﺩﺩﺩﺩﺩﻩ‬ ‫ﺩﺩﺩﺩﺩﺩﺩﻯ‬ ‫ﺭﻭﺵ‬ ‫ﺩﺩﺩ‬ ‫ﺍﻁﻁﻁﻁﻁﻁ‬ ‫ﺍﺍﺍﻥ‬ :‫ﻯﻯﻯﻯ‬ ‫ﺯﺯﺯﺁﻭﺍ‬ ‫ﺯﻥﻥﻥ‬ ‫ﺩﺭ‬ ‫ﺍﻥﻥﻥﻥﻥﻥ‬ ‫ﺭﻭﺵ‬ ‫ﺍﺍﺍﺍﻥ‬ ‫ﺍﺍﺍ‬ ..... ‫ﺍﻕﻕﻕ‬ ‫ﺍ‬ ‫ﺭﺭﺭﺍ‬ ‫ﻭ‬ ‫ﺍﻕﻕﻕ‬ ‫ﺍﺩﺩﺩﺩ‬ ‫ﺭﺭﺭﺭﺭ‬ ‫ﻭ‬ ‫ﺯﺁﻭﺍ‬ ‫ﺯﻥ‬ ‫ﺍ‬ ‫ﺫﺏ‬ :‫ﻯ‬ ‫ﺕ‬ ‫ﺍ‬ ‫ﺫﺏ‬ ‫ﺍﻕ‬ ‫ﺁ‬ 1393 ‫ﺭﺭﺭﺭ‬ / 1 ‫ﺭﺭﺭﺭﻩ‬ /4 ‫ﺭﺭﺭ‬ ‫ﺍ‬ ‫ﻭ‬ ‫ﺍﺍﺍﺍ‬ ‫ﺍﺍﺍﺍﻥ‬ ‫ﻡﻡﻡﻡ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﺍﺍﺍ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﻯ‬ @@@@ ‫ﺍﺍﺍﺍ‬ ‫ﻭﻭﻭﻩ‬ ‫ﺍﺩﺩﺩﺩ‬-1 ‫ﺍﺍﺍﺍﻥ‬ ‫ﻡﻡﻡﻡ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﺍﺍﺍ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﻯ‬ @@@@ ‫ﺍﺍﺍﺍ‬ ‫ﻭﻭﻭﻩ‬ ‫ﺩﺍﺭﺭﺭﺭﺭ‬-1 ‫ﺍﺍﺍﺍﻥ‬ ‫ﻡﻡﻡﻡ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﺍﺍﺍ‬ ‫ﺩﺍﻩﻩﻩﻩﻩ‬ ‫ﺍﻯ‬ @@@@ ‫ﺍﺍﺍﺍ‬ ‫ﻭﻭﻭﻩ‬ ‫ﺍﺭ‬ ‫ﺭﺭﺭﺱﺱﺱﺱ‬ ‫ﺩﺍﻱﻱﻱﻱﻱ‬-1 92/11/2 :‫ﺵﺵﺵﺵﺵ‬ ‫ﺭﺭﺭ‬ 92/ Abstract Introduction: The previous studies have used fibrous absorbents usually in the form of cone-shaped wedges for making anechoic and semi-anechoic chambers which their design and construction have been costly and difficult. The present study aimed to design a semi-anechoic chamber, using rectangular fibrous absorbents and also perform acoustic analysis for it. Material and Method: In the present study, which was done at semi-anechoic chamber of the laboratory in Tehran University of Medical Sciences. The reverberation time, the total surface and the absorption surface of the chamber were determined, before and after the design and also they were compared with the target values. Intersection layout of the rectangular fibrous absorbents were design using graphic design software (AutoCAD and 3Ds Max). before design, the reverberation time were measured according to ISO 3382:2000. The reverberation time in redesigned chamber was also calculated through retention time equation (Sabine). Moreover, Sabin's formula was applied for determining the absorption surface and the total surface of the chamber, before and after the design. Result: Before design, the reverberation time in the cutoff frequency of 250 Hz according to ISO 3382:2000 was determined 0.3 second. Moreover, the total chamber surface was 47.97 m2. CAD software estimated at least 253 rectangular absorbents with dimensions of 50×18 cm. After design, the absorption surface and the total chamber surface were obtained 46.32 m2 and92.64 m2, respectively and the reverberation time in the mentioned frequency was 0.07 (s). Conclusion: According to the results, it can be concluded that the suggested intersection layout of rectangular fibrous absorbents can be used as a reliable method in order to reduce the reverberation time and to gain lower cutoff frequency for construct a semi anechoic chamber with the high efficiency.
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