Abstract
Most of commercial ultrasonic phased array systems implement B- and C-scan methods based on flight time and amplitude of flaw echoes. However these methods stand on the fundamental ray-tracing theory in a homogeneous media and are not directly applicable to heterogeneous media because of complicated phenomena of wave propagation. Time reversal techniques are adaptive methods that can be used in nondestructive evaluation to improve flaw detection in heterogeneous media. Here we propose a simulation-aided flaw imaging method combined with the time reversal approach. Scattered waves from a flaw are recorded with an array transducer and the time-reversed waves are re-emitted in the numerical simulation. The simulation is based on the finite integration technique and image-based modeling. The re-emitted waves propagate through the heterogeneous media and focus on the flaw. The flaw shape can be estimated visually through the focal point of the ultrasonic wave in the simulation.
