Utilización de un tubo de impedancia basado en la norma UNE EN-ISO 10534-2 para la determinación del coeficiente de absorción acústica para materiales aislantes, aplicados en actividades de mantenimiento

Abstract

The objective of this study was to use an impedance tube based on the UNE-EN-ISO 10534-2 standard to determine the acoustic absorption coefficient for insulating materials applied in maintenance activities. The development of the work included the design of the prototype, dimensional calculations, selection of the type of material, assembly, and assembly. The theoretical foundations related to the design parameters were studied and subsequently applied in constructing the impedance tube, according to the UNE-EN-ISO 10534-2 standard. The impedance tube was installed in an area that competes with the materials laboratory of the Faculty of Mechanics of ESPOCH. A signal generator was used in the operation test, and two ¼ condenser microphones were used to capture data. An NI 9234 data acquisition card adapted to the LabVIEW software was used to analyze the acoustic absorption coefficient. The Test with three different materials, such as glass, aluminum, and polyurethane foam, to then be compared with each other concerning the vacuum data; the test frequencies varied from 125 Hz to 2000 Hz, receiving sound pressure data for a time of 10 seconds and then being exported to MATLAB for the calculation of acoustic impedance and analysis of absorbed sound. From 1000 Hz to 2000 Hz, the aluminum had a higher impedance, around 0,013 Pa s/m, than the glass with 0,003 Pa s/m. And finally, the polyurethane foam acted as a sound amplifier at around -0,02 Pa s/m. Concluding that the materials became more absorbent at higher frequencies, coinciding with bibliographies of research already carried out. It is recommended to continue with the research and analysis work to establish the optimal procedure for using and applying the equipment.