Jorge Gabriel Segura Alcaraz

ANALYSIS OF IMPACT SOUND INSULATION PROPERTIES OF RECYCLED RUBBERS FOR TECHNICAL FLOORING IN FITNESS FACILITIES

This work is a comparative analysis of the dynamic stiffness in plates made from recycled rubber intended for their use in technical flooring. The aim is to determine which one of the materials presents the best sound absorbing properties when impact loading conditions for their application in fitness facilities. In addition, the manufacturing of these materials contributes to the optimization of the industrial wastes and reduces the damage to the environment. The recommendations of the standard UNE-EN 29052-1 are considered to determine the dynamic stiffness. The results demonstrate that this product is suitable for its application in technical floors for certain sport activities, because of its low dynamic stiffness, what means that these materials have the capability to isolate the impact sounds quite well. This study is part of a more extensive research project in which some other acoustic parameters are determined, such as the sound transmission loss. Keywords—Impact Sound Insulation, Recycled Rubbers, Technical Flooring.

ESTIMACIÓN DE LA ABSORCIÓN ACÚSTICA DE PANELES FABRICADOS CON NEUMÁTICOS RECICLADOS

ABSTRACT: The present study is conducted to characterize multilayer acoustic panels made from recycled tire rubbers (GTR’s) in order to determine the sound absorption characteristics of these new materials for different applications, trying to give an answer to the environmental problem generated by this waste. This waste is currently used as modifier of asphalt, sport surfaces, molded and calendered products. The article is a first step to evaluate the sound absorption of these new multilayer panels for application in fields such as noise barriers, noise of machinery and equipment, conditioning acoustic enclosures, etc.. Basically two types of products can be obtained from the waste of the tyres: fibers and rubbers. Two types of multilayer panels of thickness 10 mm and 20 mm have been made for a three layer disposition: rubber-fibre-rubber. Then, the standing wave tube method has been used to determine the sound absorption in these materials. For rubber there are 0,7 mm and 2,2-4 mm granulometry. The results show that multilayer panels made of 2,2-4 granulometry present a higher acoustic absorption in the studied frequency range (400-3500 Hz). By increasing the thickness of the panel, the sound absorption coefficient is higher and the multilayer panel increases its sound absorption by adding more percentage of rubber.

Experimental Investigation and Numerical Simulation of the Acoustic Waves Propagation in a Standing Wave Tube: Testing with a Sample of Rockwool

Characterization of sound-absorbing materials is one of the investigation fields that is acquiring most interest in the last few years. As a consequence, there is an increase in investigators who are trying to obtain mathematical models to predict the acoustical behavior of the materials, as well as those who are looking for new materials to improve the acoustic isolation and acoustic conditioning. There are lots of applications, such as mufflers used in engines, in which it is of great interest to know the velocity of sound waves and the pressure distribution inside ducts. In this paper, the numerical simulation technique based on the finite element method is applied to study the propagation of the plane acoustic waves inside a standing wave tube by means of the application of a harmonic analysis, studying the distribution of pressures in an established frequency range. ANSYS software has been used to compare the numerical results with the theoretical ones. Then, comparing the numerical results with the experimental ones, the validity of the experimental method is evaluated. The experimental method follows the Standard ISO 10534-2 that is used for the determination of the absorption coefficient and acoustic impedance in porous and fibrous materials.