Characterization of immersed transversely isotropic rods by inversion of acoustic scattering data.

An ultrasonic technique is proposed for measurement of the elastic constants of a transversely isotropic cylindrical sample. This technique can measure all five elastic constants of a transversely isotropic rod or fiber nondestructively. The immersed rod is insonified first by a normally incident, and then by an obliquely incident, ultrasonic wave and the backscattered pressure amplitude spectra, form functions, are measured. The elastic constants of the transversely isotropic cylindrical sample are then extracted from these form functions by an inversion process. The inversion process is based on a genetic algorithm and matches a theoretical model to the measured form functions at resonance points. The proposed approach is simple and very accurate. (C) 2015 Acoustical Society of America.