title: Acoustical properties of double porosity granular materials.
abstract: Granular materials have been conventionally used for acoustic treatment due to their sound absorptive and sound insulating properties. An emerging field is the study of the acoustical properties of multiscale porous materials. An example of these is a granular material in which the particles are porous. In this paper, analytical and hybrid analytical-numerical models describing the acoustical properties of these materials are introduced. Image processing techniques have been employed to estimate characteristic dimensions of the materials. The model predictions are compared with measurements on expanded perlite and activated carbon showing satisfactory agreement. It is concluded that a double porosity granular material exhibits greater low-frequency sound absorption at reduced weight compared to a solid-grain granular material with similar mesoscopic characteristics.
authors.affiliation: Acoustics Research Centre, University of Salford, Salford M5 4WT, England. r.g.venegascastillo@edu.salford.ac.uk
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Venegas
authors.forename: Olga
authors.initials: O
authors.lastname: Umnova
mesh_terms: D000042:Absorption; D000162:Acoustics / Q000295:instrumentation*; D000537:Aluminum Oxide; D002244:Carbon; D003198:Computer Simulation; D004867:Equipment Design; D008962:Models, Theoretical; D009038:Motion; D009622:Noise / Q000517:prevention & control*; D009716:Numerical Analysis, Computer-Assisted; D016062:Porosity; D011312:Pressure; D015203:Reproducibility of Results; D012822:Silicon Dioxide; D013499:Surface Properties; D013814:Thermal Conductivity; D013997:Time Factors; D014783:Viscosity
chemical_list: C003076:Perlite; D002244:Carbon; D012822:Silicon Dioxide; D000537:Aluminum Oxide