Abstract
Most commercial ultrasonic phased array systems implement B- and C-scan methods which use flight time and amplitude of flaw echoes. However, these methods are based on the fundamental ray-tracing theory in homogeneous media, and they are not directly applicable to heterogeneous media because of the complicated phenomenon of wave propagation. Time reversal techniques are adaptive methods that can be used in nondestructive evaluation to improve flaw detection in heterogeneous media. In this study, we propose a simulation-aided flaw imaging method based on the time reversal approach. Scattered waves from a flaw are recorded using an array transducer, and the time-reversed waves are re-emitted in the image-based FIT simulation. The re-emitted waves propagate through the heterogeneous media and focus on the flaw. The shape of the flaw can be visually estimated from the focal point of the ultrasonic wave in the simulation.
