Evaluation of Hidden Corrosion in a Thin Plate Using a Non-Contact Guided Wave Technique

Review and comparison of shearography and active thermography for nondestructive evaluation

“…Therefore, nondestructive evaluation plays a crucial role for both in-service maintenance and repair verification, thus it minimizes the downtime due to unexpected critical failure. Conventional NDT techniques such as ultrasonic [77][78] and eddy current [79][80] methods are inherently handicapped for such a massive operation because of sensor limitation. On the other hand, shearography, being full-field and contact-less, is found favorable for such requirements.…”

“…Corrosion attack on pipes is a serious issue for the petrochemical industry and routine maintenance for the tens of millions of kilometers of pipes used worldwide became an impossible mission for conventional point-by-point NDT techniques such as ultrasonic thickness gauge in terms of both time and cost. A number of NDT techniques were currently employed for corrosion detection in pipes, including magnetic flux leakage (MFL) [85][86][87], ultrasonic guided wave [77][78], eddy current [79][80] and near-field millimeter-wave [88]. However, some of these techniques are still limited to point-bypoint measurement and substantial data post-processing is required to determine the exact location of corroded defects.…”