Poisson’s ratio of foamed aluminum determined by laser Doppler vibrometry

Foamed aluminum is a promising candidate in hydroacoustics as a possible pressure-release material. Previously, the measurement of its dynamic shear modulus has been reported for various densities and pore sizes of the material, [Proc. IEEE, 1985 Ultrasonics Symp. 2, 1052–1055 (1985)]. In an attempt to complete the characterization of the material, its Young’s modulus and Poisson’s ratio were measured by means of laser Doppler vibrometry. The lowest value for the ρc product found was 0.20 SI Mrayl, about 15% of the ρc product of water. Some of the samples appear to be anisotropic. An attempt was made to measure the five compliance coefficients of one foamed-aluminum type that follow from assuming uniaxial symmetry. The results did not conform to the relationships pertinent to this type of symmetry.