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Resonant ultrasound spectroscopy for materials with high damping and samples of arbitrary geometry
Author(s) -
Remillieux Marcel C.,
Ulrich T. J.,
Payan Cédric,
Rivière Jacques,
Lake Colton R.,
Le Bas PierreYves
Publication year - 2015
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2015jb011932
Subject(s) - resonant ultrasound spectroscopy , isotropy , laser doppler vibrometer , anisotropy , tensor (intrinsic definition) , transverse isotropy , computational physics , materials science , spectroscopy , physics , geometry , optics , acoustics , mathematical analysis , mathematics , laser , quantum mechanics , elastic modulus , distributed feedback laser , composite material
Resonant ultrasound spectroscopy (RUS) is a powerful and established technique for measuring elastic constants of a material with general anisotropy. The first step of this technique consists of extracting resonance frequencies and damping from the vibrational frequency spectrum measured on a sample with free boundary conditions. An inversion technique is then used to retrieve the elastic tensor from the measured resonance frequencies. As originally developed, RUS has been mostly applicable to (i) materials with small damping such that the resonances of the sample are well separated and (ii) samples with simple geometries for which analytical solutions exist. In this paper, these limitations are addressed with a new RUS approach adapted to materials with high damping and samples of arbitrary geometry. Resonances are extracted by fitting a sum of exponentially damped sinusoids to the measured frequency spectrum. The inversion of the elastic tensor is achieved with a genetic algorithm, which allows searching for a global minimum within a discrete and relatively wide solution space. First, the accuracy of the proposed approach is evaluated against numerical data simulated for samples with isotropic symmetry and transversely isotropic symmetry. Subsequently, the applicability of the approach is demonstrated using experimental data collected on a composite structure consisting of a cylindrical sample of Berea sandstone glued to a large piezoelectric disk. In the proposed experiments, RUS is further enhanced by the use of a 3‐D laser vibrometer allowing the visualization of most of the modes in the frequency band studied.