Baseline-free Ultrasonic Crack Evaluation In A Welded Joint Structure

This paper proposes a stripe-PZT sensor-based baseline-free crack diagnosis technique in the heat affected zone (HAZ) of a structure with a welded stiffener. The proposed technique enables to identify and localize a crack in HAZ using only current data measured using a stripe-PZT sensor. The main achievements of this paper are stated as follows:First, a new crack detection system named stripe-PZT sensor is developed by the author group. The use of the stripe-PZT sensor makes it possible to significantly improve the applicability to real structures and minimize man-made errors associated with the installation process by embedding multiple piezoelectric sensors onto a printed circuit board.Moreover, a new frequency-wavenumber (f-k) domain analysis-based baseline-free crack diagnosis algorithm minimizes false alarms caused by environmental variations by avoiding simple comparison with the baseline data accumulated from the pristine condition of a target structure is developed corresponding to the stripe-PZT sensor.The proposed technique is numerically as well as experimentally validated using a plate-like structure with a welded stiffener, reveling that it successfully identifies and localizes a crack in HAZ.