Title :
Application of surface impedance approach to ultrasonic wave propagation in layered anisotropic media
Author :
Levent Degertekin, F. ; Honein, B.V. ; Khuri-Yakub, B.T.
Author_Institution :
Edward L. Ginzton Lab., Stanford Univ., CA, USA
Abstract :
Matrix methods have been extensively used for wave propagation problems in layered media. Direct application of these methods using partial waves or transfer matrix formulation result in numerical problems known as exponential dichotomy. In this paper, we use the concept of surface impedance tensor to tackle this problem. Given the surface impedance tensor along an initial surface, a recursive algorithm is used to calculate the surface impedance tensor for the other layers. The methodology inherently prevents exponential dichotomy. We present applications of the surface impedance approach to practical problems. As examples, we consider the anisotropy of SAW velocity for different electrical boundary conditions, plane wave reflection from immersed layered structures with general anisotropy, and internal field distributions for predicting defect detection sensitivity
Keywords :
acoustic impedance; surface acoustic waves; ultrasonic materials testing; ultrasonic propagation; SAW velocity; defect detection sensitivity; electrical boundary condition; exponential dichotomy; immersed structure; internal field distribution; layered anisotropic medium; numerical method; partial waves; plane wave reflection; recursive algorithm; surface impedance tensor; transfer matrix; ultrasonic wave propagation; Anisotropic magnetoresistance; Boundary conditions; Equations; Matrices; Nonhomogeneous media; Surface acoustic wave devices; Surface acoustic waves; Surface impedance; Surface waves; Tensile stress;
Conference_Titel :
Ultrasonics Symposium, 1996. Proceedings., 1996 IEEE
Conference_Location :
San Antonio, TX
Print_ISBN :
0-7803-3615-1
DOI :
10.1109/ULTSYM.1996.584044