Anisotropic media for elastic wave mode conversion, shear mode ultrasound transducer using the anisotropic media, sound insulating panel using the anisotropic media, filter for elastic wave mode conversion, ulstrasound transducer using the filter, and wave energy dissipater using the filter

摘要

The anisotropic media has an anisotropic layer, is disposed between outer isotropic media, causes multiple mode transmission on an elastic wave having a predetermined mode incident into the anisotropic media, and has a mode-coupling stiffness constant not zero. A thickness of the anisotropic layer according to modulus of elasticity and excitation frequency satisfies Equation (2) which is a phase matching condition of elastic waves propagating along the same direction or Equation (3) which is a phase matching condition of elastic waves propagating along the opposite direction, to generate mode conversion Fabry-Pérot resonance,Δϕ≡kqld−kqsd=(2n+1)π,   Equation (2)Σϕ≡kqld+kqsd=(2m+1)π,   Equation (3)kql is wave numbers of anisotropic media with quasi-longitudinal mode.lqs is wave numbers of anisotropic media with quasi-shear mode. d is a thickness of anisotropic media. n and m are integers.