摘要: The extended boundary condition (EBC) or T-matrix method was first developed todescribe electromagnetic scattering from bounded objects and later for acoustical targets. The method was then extended to the much more difficult prob... 展开 The extended boundary condition (EBC) or T-matrix method was first developed todescribe electromagnetic scattering from bounded objects and later for acoustical targets. The method was then extended to the much more difficult problem of elastic targets in a fluid and elastic environment leading to several T-matrix methods. In this work we show how it is possible to enhance the above methods by numerical or structural improvements. Some of the improvements presented are: (1) the coupled higher-order T-matrix that couples the required incident partial waves to the required surface expansion terms, which reduces the need of a square matrix; (2) an eigenexpansion method; (3) a unitary method which constrains the T-matrix to satisfy symmetry and conservation of flux. Results are presented to demonstrate that these methods can describe rigid spheroids to aspect ratios of at least 30 to 1 for kL/2 values above 200. For elastic solids results will be shown for spheroids up to 10 for kL.2 out to at least 18 and the presence of flexural or bending resonances will be demonstrated for elastic spheroids. Elastic shells present a greater problem but we have been able to obtain results for aspect ratios above 3 to 1. 收起