Enhancement of Flaw Detectability Using Time Reversal Techniques

Ultrasonic phased array inspection has been paid a great attention in ultrasonic nondestructive evaluation since it can provide a benefit of focusing and/or steering ultrasonic beams. A time reversal technique is claimed to be very robust to focus beams through inhomogeneous media, using the phased array transducers. In this paper, the performance and limitations of a D.O.R.T. method, which is one of the time reversal techniques, is considered based on the experimental studies. In addition, a variation of the D.O.R.T, namely a pre-focused D.O.R.T., is proposed in order to overcome the limitations of the current D.O.R.T. method. The results of the newly proposed method are compared to those obtained by conventional focusing methods.