Análisis de absorción en baja frecuencia que produce el uso de varias capas de material absorbente y diferente distribución mediante método analítico y medición con estándares tipo ISO

Absorption coefficients represent the capacity of sound absorption acoustic materials. This parameter is estimated from measurements such as those specified in ISO type parameters. As for example, regulation 354 estimates the coefficient of absorption at random incidence through the measurement in reverberant chamber and regulation 10534 estimates the absorption at normal incidence using as a tool a tube of standing waves. Most manufacturers of absorbent materials have the estimated absorption coefficient between the frequencies of 125 Hz to 4000 Hz. The low frequency range is usually not reported since the absorption coefficient is not relevant, although it is also of interest in the implementation and therefore an evaluation is necessary. This project aims to find a methodology that allows, through international methods and analytical methods, to estimate the absorption coefficient at low frequency when the thickness of three absorbent materials increases, Frescasa (glass wool), Acustiplaca (pressed rock wool) and Acustifibra (pressed glass wool). The study focuses on the study of frequencies between 63 Hz to 250 Hz, in addition to this, the effect of estimating the absorption coefficient on different distributions is investigated. For this purpose, panels with several layers of absorbent material have been designed to be measured by ISO 354, placing the panels in two positions, vertical and horizontal. The absorption coefficient is estimated using several layers of absorbent material according to ISO 10534-1 in impedance tube. With the proposed methodology, the measurements in the impedance tube were analyzed according to layers of material to determine how to modify the absorption coefficient as the thickness increases. In a reverberant chamber, measurements can be made with the multilayer panels in a vertical position and in a horizontal position. As an analytical method, the Allard and Champoux absorption model is implemented by varying the thickness of the materials and taking into account the resistivity value for each material. With the results obtained, it was concluded that the thickness of the absorbent materials increases, which represents an increase in the absorption coefficient at low frequencies and is also a physical characteristic that predominates over density. However, it is necessary in future studies to define the feasibility of this method, in order to optimize the strategies that are required in each case of acoustic conditioning that link problems in low frequency.

• Autores: Arias Arboleda, Susana
• Fecha de publicación: 2020
• Institución: Universidad de San Buenaventura
• Repositorio: Repositorio USB
• Idioma: spa
• OAI Identifier: oai:bibliotecadigital.usb.edu.co:10819/7966
• Acceso en línea: http://hdl.handle.net/10819/7966
• Palabra clave: Coeficiente de absorción; Materiales absorbentes; Incidencia aleatoria; Incidencia normal; Espesor; Tiempo de reverberación; Absorption coefficient; Absorbent materials; Random incidence; Normal incidence; Reverberation time; Thickness; Absorción del sonido
• License: Atribución-NoComercial-SinDerivadas 2.5 Colombia