Application of conformal map theory for design of 2-D ultrasonic array structure for ndt imaging application : a feasibility study

Ramadas, Sivaram Nishal and Jackson, Joseph and Dziewierz, Jerzy and O'Leary, Richard and Gachagan, Anthony (2014) Application of conformal map theory for design of 2-D ultrasonic array structure for ndt imaging application : a feasibility study. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 61 (3). pp. 496-504. ISSN 0885-3010

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    Abstract

    Two-dimensional ultrasonic phased arrays are becoming increasingly popular in nondestructive evaluation (NDE). Sparse array element configurations are required to fully exploit the potential benefits of 2-D phased arrays. This paper applies the conformal mapping technique as a means of designing sparse 2-D array layouts for NDE applications. Modeling using both Huygens' field prediction theory and 2-D fast Fourier transformation is employed to study the resulting new structure. A conformal power map was used that, for fixed beam width, was shown in simulations to have a greater contrast than rectangular or random arrays. A prototype aperiodic 2-D array configuration for direct contact operation in steel, with operational frequency ~3 MHz, was designed using the array design principle described in this paper. Experimental results demonstrate a working sparse-array transducer capable of performing volumetric imaging.