Review of Test Methods for Material Properties of Elastic Porous Materials

Biot's model of elastic porous materials is widely used to predict the acoustical performance of noise control materials in the automotive industry. Material properties of acoustical materials, often referred to as Biot parameters, such as porosity, airflow resistivity, tortuosity, viscous characteristic length and thermal characteristic length are required inputs in the Biot model. Various test methods have been developed to measure Biot parameters. This paper conducts a comprehensive review of the existing test methods, discusses accuracy and applicability of each test method, and provides recommendations to the SAE Acoustical Materials Committee regarding the need for the development of SAE test methods for Biot parameters.