APMR : Acoustical Porous Material Recipes

The aim of this site is to gather information about works in the field of acoustical porous materials: models for the propagation of sound, parameter definitions and characterization techniques, standards...

 

Content

Propagation models

• Motionless skeleton (equivalent fluid)
• Delany-Bazley
• Delany-Bazley-Miki
• Horoshenkov et al.
• Johnson-Champoux-Allard
• Johnson-Champoux-Allard-Lafarge
• Johnson-Champoux-Allard-Pride-Lafarge
• Wilson
• Uniform pressure (equivalent solid)
• Diphasic (Biot's theory)
• Linking micro-structure to macro-properties

Parameters of models

• Static air flow resistivity (& static permeability)
• Open porosity
• High frequency limit of the dynamic tortuosity
• Viscous characteristic length
• Thermal characteristic length
• Static thermal permeability

Characterization of parameters

• Static air flow resistivity (& permeability)
• Open porosity
• High frequency limit of the dynamic tortuosity
• Viscous characteristic length
• Thermal characteristic length
• Static thermal permeability
• Conditions on parameters

Basics of Acoustics

• Some physical phenomena
• Compressional wave
• Propagative vs. standing waves
• Wave number
• Wave dispersion
• Length corrections
• Darcy's law
• Viscous boundary layer
• Helmholtz resonator
• Transmission Loss of a single partition
• The coincidence frequency

Basics of Mechanics

• Single degree of freedom (SDOF) systems
• Solution to undamped 1D harmonic oscillator
• Beam bending (compute eigenfrequencies)
• Comparison of damping models
• Snell-Descartes to variational principles
• Variational methods
• Flow around a disk
• Limits of plate theories
• Condensed models for multilayer structures

Basics of Materials

• Material classes
• A note about "meta-materials"
• A note about fractional derivatives
     used in some visco-elastic models

Standards

• A list of standards for acoustical materials
• Octave and third-octave bands from ISO 3
• Sound Absorption Average from ASTM C423

Upcoming events

Below are conferences or events for which one or more sessions on acoustical porous materials are organized.

Forum Acusticum 2025

June 23-26, 2025 - Malaga (Spain)

Abstract submission deadline: January 19, 2025
Early bird registration: April 20, 2025

Internoise 2025

August 24-27, 2025 - Sao-Paulo (Brazil)

Abstract submission deadline: Feb. 9, 2025
Early bird registration: May 18, 2025

SAPEM 2026 (Symposium on the Acoustics of Poro-Elastic Materials)

Exact dates to be announced soon (November 2026)