Abstract
The present study investigated crack visualization in circular pipe using Kriging model and time-domain reflectometry (TDR) with helix microstrip line (MSL). The proposed method was enabled by covering the inspected structure surface with the microstrip conductor without having a bent. The crack visualization experiments were conducted using Kriging model and TDR with helix MSL. The experimental results demonstrated that the crack position could be clearly visualized. Because it only detects the damage beneath the transmission line, the reliability of the estimation between sensor lines is low. We used a Kriging model to visualize the uncertainty of the estimated damage location from TDR measurements. We integrated the estimation and uncertainty contour maps into a single figure for easier understanding and statistical quantification. The visualization of the crack existence probability enables inspectors to judge the crack existence more intuitively using statistically quantitative evidence compared to the separate visualizations of the estimated value and its uncertainty.
