FOAM-X

Identification of acoustic modeling parameters of porous materials

Overview

During the process of designing acoustic treatments including porous materials, the definition of the modeling parameters of these materials is a critical step.

FOAM-X makes it possible to obtain the acoustic modeling parameters of porous materials from standard tests.

FOAM-X identification algorithms use acoustic measurements obtained by impedance or transmission tube using ASTM E1050, ISO 10534-2 and ASTM E2611 standards. From the absorption coefficient or the dynamic compressibility modulus and the dynamic density, the software calculates the acoustic modeling parameters of open-cell porous materials: the open porosity, the resistivity to the passage of static air, the tortuosity , viscous and thermal characteristic lengths, static thermal permeability, Young's modulus, Poisson's ratio and structural damping factor.

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Software characteristics

FOAM-X software works with all standards related to impedance and transmission tube ASTM E1050, ISO 10534-2 and ASTM 2611 (direct acoustic measurement).

FOAM-X can characterize several types of open-cell porous materials (foam, fibrous, perforated sheet, resistive screen, fabric)

The software can characterize three types of structure (rigid, flexible, elastic).

FOAM-X has a simulation and sensitivity study tool (analytical and numerical solver) which takes into account the boundary conditions of the assembly of the material in the tube (tight, slippery material, with air leaks).

FOAM-X has its own database which makes it possible to store, search and compare the identified materials. The results of FOAM-X are written in an XML file compatible with VA One software from ESI Group and NOVA.

FOAM-X can extract the following data

The resistivity to the passage of static air

The structural damping factor

Tortuosity

Young's modulus

The thermal characteristic length;

open porosity

The viscous characteristic length

Static thermal permeability

Poisson's ratio

Videos, tutorials and photos of the software

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Inverse method

Rapid characterization

Foam-X

Additional features

Identification of acoustic modeling parameters

  • Calculates the mean and standard deviation of the data set;

  • Corrects tube and measurement conditions (temperature, atmospheric pressure and relative humidity);

  • The user can provide parameters to improve convergence (density, resistivity, porosity, tortuosity and other parameters);

  • Identification according to three types of skeleton (rigid, flexible or elastic);

  • Identification over a range of frequencies (min, max).

Display, simulation and sensitivity analysis

  • Validation of the parameters obtained by comparison of simulations using analytical or numerical poroelastic models (finite elements) with impedance/transmission tube measurements;

  • Plots both predicted and measured data (if available) of:

    • Absorption, reflection or surface impedance coefficient;

    • Attenuation index;

    • Dynamic properties (characteristic impedance, wave number, effective dynamic density, effective bulk modulus);

    • Backup (export).

    • The software simulates the effects of boundary conditions and lateral acoustic leakage in tubes by the axisymmetric finite element method (axiFEM);

  • The software predicts all the acoustic properties in the case of excitation by a plane wave of normal incidence such as: the absorption coefficient, the attenuation index, the surface and characteristic impedance, the number of complex wave, the effective dynamic density and the effective bulk modulus;

  • The simulations take into account:

    • The type of termination (air cavity, rigid bottom or anechoic);

    • Boundary conditions (embedded, sliding, with air leaks);

    • The type of skeleton (rigid, flexible and elastic);

    • Material thickness and diameter;

    • Atmospheric conditions;

    • Parameter uncertainties.

Database

  • Retains materials identified by FOAM-X or your own method;

  • Searches for materials according to different criteria (e.g. price, porosity, resistivity to the passage of air, thickness, etc.);

  • Compare two materials.

FOAM-X

Identification of acoustic modeling parameters of porous materials