Tractable calculation of the Green's tensor for shear wave propagation in an incompressible, transversely isotropic material
Tractable calculation of the Green's tensor for shear wave propagation in an incompressible, transversely isotropic material
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DOI：
10.1088/1361-6560/ab5c2d
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发表时间：
2020-01-01
影响因子：
3.5
通讯作者：
Nightingale, Kathryn R.
中科院分区：
文献类型：
--
作者：
Rouze, Ned C.;Palmeri, Mark L.;Nightingale, Kathryn R.
在各向异性材料中，由于传播方向、横波偏振和材料对称性之间的复杂关系，通过声辐射力脉冲(ARFI)激励后的横波传播的观测来评估材料的性能是困难的。本文描述了一种用格林张量方法计算三参数不可压缩横观各向同性(TI)材料中横波信号的方法。格林张量被写成SH传播模式的解析表达式和SV传播模式的积分表达式的和，该积分表达式可以通过在预计算积分函数内进行内插来计算，其效率与闭合形式的表达式的计算相当。通过使用参数化积分函数，根据所考虑的具体问题，所需的数值积分的数量减少了10(2)-10(9)倍。给出了一个位于原点的点源和一个类似于Arfi激励的高斯源的结果。对于倾斜材料对称轴的实验配置，结果表明，横波信号表现出足够复杂的结构，以允许测量表征不可压缩的TI材料的所有三个材料参数。
Assessing material properties from observations of shear wave propagation following an acoustic radiation force impulse (ARFI) excitation is difficult in anisotropic materials because of the complex relations among the propagation direction, shear wave polarizations, and material symmetries. In this paper, we describe a method to calculate shear wave signals using Green's tensor methods in an incompressible, transversely isotropic (TI) material characterized by three material parameters. The Green's tensor is written as the sum of an analytic expression for the SH propagation mode, and an integral expression for the SV propagation mode that can be evaluated by interpolation within precomputed integral functions with an efficiency comparable to the evaluation of a closed-form expression. By using parametrized integral functions, the number of required numerical integrations is reduced by a factor of 10(2)-10(9) depending on the specific problem under consideration. Results are presented for the case of a point source positioned at the origin and a tall Gaussian source similar to an ARFI excitation. For an experimental configuration with a tilted material symmetry axis, results show that shear wave signals exhibit structures that are sufficiently complex to allow measurement of all three material parameters that characterize an incompressible, TI material.