Flexible ultrasonic transducer arrays for nondestructive evaluation applications. I. The theoretical modeling approach

This paper presents the development of a theoretical modeling strategy to be used in the design of flexible ultrasonic transducer arrays. These new types of array device are intended for those applications where surface conformity is desirable. Such array structures allow much more efficient and effective coupling of acoustic energy between the transducer and test specimen than would have been otherwise possible with an equivalent rigid device. The objective of this work is to provide the transducer designer with a set of design tools that will permit the analysis of different material configurations and various transmit-receive aperture designs. Linear systems modeling is used to evaluate, and consequently optimize, the transduction performance, while a surface scattering model has been developed to facilitate the analysis of different transmit-receive aperture configurations. A theoretical modeling approach for flexible arrays is developed and where necessary, the validity confirmed by experimental measurement.