Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2342
O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Engenharia Mecânica (PPGEM) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Item Acesso aberto (Open Access) Desenvolvimento de painéis confeccionados a partir de fibras de coco para controle acústico de recintos(Universidade Federal do Pará, 2008-10-31) VIEIRA, Rodrigo José de Andrade; SOEIRO, Newton Sure; http://lattes.cnpq.br/7303174583088137A reasonable alternative for noise control in enclosures is based on the use of sound absorption materials (porous and fibrous), which convert acoustic energy into heat, due to air viscosity. The material acoustic absorption characteristic is determined by its sound absorption coefficient, which depends mainly on frequency, sound incidence angle, density, thickness and internal structure of the material. From the Amazon, due to its enormous biodiversity, thousands of natural products and sub products are retrieved, some of which are not completely used. Thus, many residues reach other industrial sectors, such is the case of the coconut fiber, which can be used in many ways. Therefore, the present work defines and describes an acoustic panel manufacturing process, based on coconut fiber, including the experimental determination of important parameters for noise control in enclosures. Also, a numerical model is implemented to investigate cost and quality control parameters, in order to assist the development and manufacturing of new panels. First, the necessary information is collected to start the development process of coconut fiber panels, following an “informational project” methodology. Next, all the steps related to the panel manufacturing process are described, looking forward to obtaining its acoustical, mechanical and physical-chemical main properties. From the numerical simulations, one tries to analyze and predict the coconut fiber panel behavior (apart from a commercially available acoustical panel), and investigate its influence over the acoustical parameters of an auditorium (reverberation time, sound pressure decay, and intelligibility). With the development of the coconut fiber panels, one expects to contribute for the creation of new sectors on the local economy, mainly considering the elevated costs of the actual acoustical panels available in the market. Finally, another outstanding advantage of the coconut fiber panels proposed here is the possibility of its usage in the context of regional architecture, where emphasis is given on local materials.Item 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/7303174583088137In 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.