Definition of analytical models of non-acoustical parameters for randomly-assembled symmetric and asymmetric radii distribution in parallel fiber structures

Fibrous materials for acoustical applications have been extensively studied over the past years. A consid-erable number of experimental tests have been carried out as a function of fiber geometrical character-istics (for example, overall density, fiber diameter and density, open porosity, etc.) in order to determineanalytical formulations for the prediction of physical parameters, primarily the airflow resistivity. Due tothe increase of computational capabilities micro-to-macro structure approach is the subject of currentresearch in order to determine transport and acoustic properties starting from certain arrangements offiber in space. Almost all research assumes fiber having the same radius with regular or random positionwithin a representative volume of material. To this end, the aim of the present paper is to provide a revi-sion of existing analytical formulations of non-acoustical parameters for two-dimensional structures hav-ing random positioning in space and symmetric and asymmetric distribution of radii. Proposedformulations will be compared with existing models and finite element simulations