Longitudinal wave attenuation in polycrystals with elongated grains: 3D numerical and analytical modeling

This work develops a second-order approximation (SOA) model and three-dimensional (3D) finite element (FE) to calculate scattering-induced attenuation for elastic wave propagation in polycrystals with elongated grains of arbitrary crystal symmetry. The SOA accounts some degree multiple scattering, whereas the 3D FE includes all scattering possibilities. incorporates accurate geometric two-point correlation function obtained from material systems enable comparative studies between two models. Also, analytical Rayleigh stochastic asymptotes are presented provide explicit insights into behaviors. Quantitative agreement is found models evaluated cases. In particular, simulations support prediction that grain shape does not exert influence on regime its effect emerges as frequency increases showing anisotropy attenuation. intensifies increase frequency, but it exhibits complicated behavior transits regime. Wavefield fluctuations captured provided help observe these complex proportionality factors also quantitatively evaluated.