ویژگی‌های انتشار موج بلند در بلورهای فونونی، اثر غلظت و پراکندگی اجزا در کامپوزیت‌های سه‌ جزیی

This paper investigates the propagation characteristics of long-wavelength acoustic waves based on wave equation solutions, boundary conditions, and Bloch's theorem, leading to a characteristic matrix equation that defines the dispersion relation. Numerical simulations explore the influence of component spatial distribution and relative concentrations on wave behavior, specifically focusing on dispersion relations, phase velocity, passbands, and stopbands across various single and multiple scattering regimes.
Key findings reveal that even with constant total material concentrations, varying the distribution of components significantly impacts passband and stopband widths. A crucial discovery is that the minimum stopband width is achieved when component concentrations are equally distributed between the two subsections of the unit cell. The study also highlights the sensitivity of phase velocity in the intermediate wavenumber range to the internal arrangement of components. These results offer valuable insights into acoustic wave control through tailored phononic crystal architectures, relevant for applications in non-destructive evaluation, acoustic filtering, and advanced metamaterials.