Navegando por Assunto "Acoustic engineering"

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Acesso aberto (Open Access)
Desempenho acústico das edificações segundo a NBR 15575 (ABNT, 2013): desempenho das vedações e validação dos requisitos normativos com base na opinião dos usuários
(Universidade Federal do Pará, 2016-03-18) SANTANA, Wylliam Bessa; PICANÇO, Marcelo de Souza; http://lattes.cnpq.br/4535052395600357
With the growth of large urban centers in Brazil, the population density and the need for housing led to high demand for semi-detached homes and apartment houses with numerous apartments, however, with the passage of time they became the result of user complaints in consequence of the low performance of the buildings. The normalization of the performance of the buildings was necessary. Several international standards address the issue, but only in 2013 was published the Brazilian standard of buildings performance NBR 15575 (ABNT, 2013), stipulating among other things, requirements for acoustic performance of internal and external walls, and slabs about the noise impact and air. However, there are some questions, such as: does the current construction typology meet these performance acoustic criteria? Are these criteria suitable? Among to answer these questions, field tests and questionnaires were performed with residents. Among the seals whose acoustic performance is required, the results show the inner walls are more distant to meet these criteria, and the external meet with difficulty, even as perceived by users. About the regulatory requirements for acoustic performance, are significant the annoyed levels generated by impact loads on slabs, highlighting the low accuracy, and even more worrying that the latter is the fact in not require acoustic performance criteria regarding the impact noise between walls, highlighted by the vast majority of respondents as the main source of noise.
Acesso aberto (Open Access)
Projeto e construção de câmaras reverberantes em escala reduzida para o estudo das características de perda de transmissão de divisórias confeccionadas a partir de materiais regionais
(Universidade Federal do Pará, 2006-09-05) TOUTONGE, José de Aviz; SOEIRO, Newton Sure; http://lattes.cnpq.br/7303174583088137
To project and build reverberant chambers, in scaled model, for the determination of materials transmission loss used for noise control purposes was the objective of this research. Besides, the research seeks to establish a methodology of analysis and interpretation of the acoustic parameters starting from the theory of scaled models, in such way that one can infer the transmission loss of the studied materials. The necessity of this construction occurs due to the non availability of real scale reverberant chambers (only available in some regions of Brazil), making it difficult and raising the costs of material performance tests in other Brazilian regions. Therefore, reverberant chambers were constructed in a reduced scale of 1:6, in order to allow the transmission loss study of party walls, developed with regional materials, confronting their performances and, simultaneously, their use in academic activities. Despite the fact of the chambers have been constructed in reduced scale, the scale factor (1:6) was not considered, meaning that measurements had been carried through in the real octave bands between 125 Hz and 8 kHz. Party walls had been assayed for the determination of the acoustic parameters, based on ISO 140 and 354. Finally, from experimental results, it was possible to prove the efficiency of materials used in the construction of partitions, which could be used for noise isolation purposes in buildings and industrial enclosures. Apart from the experimental assays, analytical calculations had been fulfilled according to the formulation of Analysis Energy Statistics (SEA) in order to provide evidence and validation of the results.
Acesso aberto (Open Access)
Projeto e construção de uma câmara reverberante em escala reduzida para a caracterização acústica de materiais absorventes
(Universidade Federal do Pará, 2007-05-31) GUEDES, Reginaldo Cascaes; SOEIRO, Newton Sure; http://lattes.cnpq.br/7303174583088137
In the area of Acoustics, concerning the last decades, a significant growth has been observed in the demand for data regarding not only the absorbing characteristics of acoustical materials, but also the usage of numerical methods which are able to represent the acoustical behavior of real systems. These real systems demand a significant infrastructure, which means a great deal of investments. Thus, in order to attend such demands for new data, to allow the development of research regarding the sound absorbing characteristics of regional materials and to develop practical classes on acoustics, both for graduate and post-graduate students, this work presents all the information regarding the project and construction of a scaled reverberant chamber (1:6 of a 200 m3 real chamber). Besides, a methodology is presented regarding the qualification and adequacy of the internal acoustic field, based on the guidance of ISO-354. On the other hand, experimental results for the miniaturized chamber are presented and discussed, which characterize and validate the usage of the coconut fiber panels, developed by the Acoustics and Vibration Group of the Federal University of Pará. Finally, numerical results, based on Ray Tracing Methods, are presented and compared to those measured for the scaled chamber, seeking the validation of the developed numerical model.