Related Experiment Video
Updated: Aug 18, 2026

Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Acoustical measurement of the shear modulus for thin porous layers
Jean F Allard1, Michel Henrya, Laurens Boeckx
1Laboratoire d'Acoustique de l'Université du Maine, UMR CNRS 6613, Avenue Olivier Messiaen, 72085 Le Mans Cedex, France.
Abstract:
Simulations performed with the Biot theory show that for thin porous layers, a shear mode of the structure can be induced by a point-source in air located close to the layer. The simulations show that this mode is present around frequencies where the quarter wavelength of the shear Biot wave is equal to the thickness of the samples and show that it can be acoustically detected from the fast variations with frequency of the location of a pole of the reflection coefficient close to grazing incidence. The mode has been detected with this method for two reticulated plastic foams. For one of the foams studied, the velocity and the damping of the Rayleigh wave have been measured on a thicker layer of the same medium at higher frequencies, giving a real part of the shear modulus close to the one obtained from the measured location of the pole. The strong coupling of the shear mode with the acoustic field in air allows the measurement of the shear modulus without mechanical excitation.
Related Concept Videos
Dynamic Modulus of Elasticity of Concrete
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by a...
Shearing Strain
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Strain and Elastic Modulus
Problem Solving on Stress and Strain
Sound as Pressure Waves
The pressure fluctuation depends on the difference in displacements between the successive points in the...

