Ultrasonic time reversal method for nondestructive materials testing

Chiraz Ennaceur and Rudolf Sprik

In the ultrasonic time reversal method waves are refocused on to a source by emitting a time-reversed version of the received wave field as measured by the same transducers. We present an experimental investigation of the applicability of the time reversal method for the nondestructive testing (NDT) of materials and its ability to detect the evolution of small damages in structures. As an example, we studied the spreading of a silicon oil droplet on an aluminum surface. The experiments show that the sensitivity and the invariance of this method can be exploited to follow and to identify the different stages of the droplet spreading. These results show that the time reversal method is a technique which can be used for structural integrity monitoring.