A Cross-Scanning Crack Damage Quantitative Monitoring and Imaging Method

Quantitative crack monitoring and detection is one of the focuses of attention in structural health monitoring, due to its concealment and harmfulness.However, the existing guided wave and PZT sensor array based structural health monitoring approaches often ignore the crack orientation information which is the key issue in the crack monitoring, so that it is hard to effectively evaluate the crack damage.In this study, the circular piezoelectric array and active Lamb wave RAPID imaging technology are introduced and improved to study the quantitative monitoring of crack damage.A cross scanning method is proposed to determine the crack orientation, based on the different degree of response signal variation on monitoring path with different angles.Accordingly, the signal difference coefficient (SDC) value of the detected monitoring path of parallel or approximate parallel crack damage is corrected to strengthen the reconstruction information of crack orientation.After that, the image reconstruction and quantitative evaluation of crack damage can be realized by the enhanced SDC information.Several experiments were carried out on the aluminum plate to validate the proposed method.The cracks in different positions and orientations were monitored and evaluated by the proposed method.The experimental results showed that the crack orientation can be identified well by the proposed cross scanning crack monitoring and imaging method.