横向各向同性柱状复合结构对超声波的散射

首先描述了横向各向同性复合圆柱结构的入射声场、散射声场及内部的驻波声场,然后利用转移矩阵方法导出了求解散射声场的方程组,计算了铝/各向异性界面层/纤维复合结构对斜入射声波的背向散射谱和散射截面积。将柱状复合结构中各向异性界面薄层相应的转移矩阵作渐近展开,建立了模拟这种界面薄层的弹簧模型及界面处广义边界条件。结果表明,模型中劲度常数仅依赖于界面薄层厚度及界面层媒质的弹性常数c_ll,c₁₂和c₄₄,而振子质量与c_ll,c₄₄,c₁₃和c₃₃有关。

Sound scattering by cylindrical layered structures with transversely isotropic symmetry

The sound fields inside and outside a cylindrical layered structure with transversely isotropic symmetry due to an obliquely incident wave are described in the paper. By using the transfer matrix approach, the linear algebraic equations in matrix form are derived to determine the potential functions of the scattered waves. Some namerical computations are made for the backscattering spectra and scattering cross-sections. A spring model for simulating an anisotropic interphase layer between, for example, a fiber core and isotropic matrix medium is developed. The generalized boundary conditions at an interphase are also given. The results indicate that the spring stiffnesses in the obtained spring model depend on the layer thickness and the elastic constants c₁₁, c₁₂ and c₄₄, while their mass terms are related with c₁₁, c₄₄, c₁₃ and c₃₃.