Transducer field modeling in anisotropic media by superposition of Gaussian base functions

Anisotropic structural materials like fiber composites, but also columnar-g rained stainless steels, raise considerable problems for ultrasonic inspect ion due to the well-known wave propagation phenomena of skewing, splitting and distortion. In this respect, simulation and optimization in ultrasonic nondestructive testing have gained a considerable importance. Among a varie ty of methods for transducer field calculation, beam superposition has prov en to be highly efficient. In this cuticle, a Gaussian beam approach for an isotropic media is presented. The Gaussian base functions are obtained from relationships previously derived for Gaussian wave packets. Each function is furnished with coefficients fixing the beam waists and their position. T o test the approach, the case of a piston radiator is addressed for general transversely isotropic media. Using Gaussian beam superposition instead of -as a reference-applying a point source superposition technique leads to an enormous reduction in computer run time. (C) 1999 Acoustical Society of Am erica. [S0001-4966(99)05101-2].