arXiv subjects

Raymond Panneton

Publications and source records attributed to Raymond Panneton.

4 recordsLinked to original sources

arXiv2023

Utilizing polydispersity in composite fibrous based sound absorbing materials

The distribution of fiber diameters plays a crucial role in the transport and sound absorbing properties of a three-dimensional random fibrous (3D-RF) composites. Conventionally, volume-weighted averaging of fiber diameters has been utilized as an appropriate microstructural descriptor to predict the static viscous permeability of 3D-RF composites. However, the long wavelength acoustical properties of a 3D-RF composites are also sensitive to the smallest fibers, this is particularly true in the high-frequency regime. In our recent research, we demonstrated that an inverse volume-weighted averaging of fiber diameters can effectively serve as a complementary microstructural descriptor to capture the high-frequency behavior of polydisperse fibrous media. In the present work, we review the identification of two representative volume elements (RVEs) which relies on the reconstruction of 3D-RF composites having volume-weighted and inverse-volume weighted averaged fiber diameters, respectively in the low-frequency and high frequency regimes. We examine the implication of such a weighting procedure on the transport and sound absorbing properties of polydisperse fibrous media, highlighting their potential advantages. Furthermore, we discuss the challenges associated with this research field. Finally, we provide a brief perspective of the future directions and opportunities for advancing this area of study, aiming to overcome challenges and extend the benefits of employing polydispersity as a new lever for the optimization of 3D-RF composites in sound-absorbing materials.

physics.flu-dyn↗

arXiv2018

How reproducible are methods to measure the dynamic viscoelastic properties of poroelastic media?

There is a considerable number of research publications on the acoustical properties of porous media with an elastic frame. A simple search through the Web of ScienceTM (last accessed 21 March 2018) suggests that there are at least 819 publications which deal with the acoustics of poroelastic media. A majority of these researches require accurate knowledge of the elastic properties over a broad frequency range. However, the accuracy of the measurement of the dynamic elastic properties of poroelastic media has been a contentious issue. The novelty of this paper is that it studies the reproducibility of some popular experimental methods which are used routinely to measure the key elastic properties such as the dynamic Young's modulus, loss factor and Poisson ratio of poroelastic media. In this paper, fourteen independent sets of laboratory measurements were performed on specimens of the same porous materials. The results from these measurements suggest that the reproducibility of this type of experimental method is poor. This work can be helpful to suggest improvements which can be developed to harmonize the way the elastic properties of poroelastic media are measured worldwide.

physics.class-ph↗

arXiv2010

Evaluation of the acoustic and non-acoustic properties of sound absorbing materials using a three-microphone impedance tube

This paper presents a straightforward application of an indirect method based on a three-microphone impedance tube setup to determine the non-acoustic properties of a sound absorbing porous material. First, a three-microphone impedance tube technique is used to measure some acoustic properties of the material (i.e., sound absorption coefficient, sound transmission loss, effective density and effective bulk modulus) regarded here as an equivalent fluid. Second, an indirect characterization allows one to extract its non-acoustic properties (i.e., static airflow resistivity, tortuosity, viscous and thermal characteristic lengths) from the measured effective properties and the material open porosity. The procedure is applied to four different sound absorbing materials and results of the characterization are compared with existing direct and inverse methods. Predictions of the acoustic behavior using an equivalent fluid model and the found non-acoustic properties are in good agreement with impedance tube measurements.

physics.class-ph↗

arXiv2006

Comparison of Methods for Characterizing Sound Absorbing Materials

Sound absorbing materials are usually defined by five parameters: open porosity, static airflow resistivity, tortuosity, and two characteristic lengths. In recent decades, different methods have been developed in order to characterize these parameters. These methods may be divided following three approaches: i) inverse, ii) indirect and iii) direct. The inverse approach is based on an optimisation problem where the material parameters are adjusted in the acoustic model to reproduce acoustical measurements. The indirect approach is based on the acoustical model from which analytical expressions linking the material parameters to acoustical measurements are derived. Contrary to the previous two approaches, the direct approach is not based on acoustical measurements. It is based on the physical and mathematical definition of the parameters and requires dedicated equipments. In this study, the five parameters have been measured for different porous materials using some direct, indirect and inverse methods. A comparison of the different results is carried out, and shows that the different methods may yield large variability in the found parameters. A discussion is given to explain the observed variability and the limitations of the methods.

physics.class-ph↗