Numerical simulation of scattered waves from flaws for ultrasonic array transducer

To enhance the detectability in the phased array UT, it is essential to have well knowledge on the characteristics of ultrasonic waves from array transducers. This paper proposes a mathematical model of the array transducer and a simulation tool to predict the flaw echoes. The modeling of an array transducer is based on the Rayleigh-Sommerfeld integral and the scattered waves from flaws are calculated with the fast multipole BEM (FMBEM). By using the FMBEM, we can solve large scale scattering problems with relatively low computational cost. Here we focus on the transient wave analysis, in which a pulse-shaped wave is used for exciting elements of the array transducer.