Identification of Pipe Damage by Line-Structured Light and Regional Resonance Pairs

Baseline-free methods in structural health monitoring (SHM) are crucial as they allow for real-time damage detection and assessment, eliminating the dependency on initial condition data. This study proposes a baseline-free damage detection method for pipes by combining line-structured light (LSL) with regional resonance pairs (RRPs). The 5 damage indices, combined with the RRP frequency ratio, enable Level 3 damage identification (detection, location, and quantification). The key idea is to sort the RRP frequencies to predict the damage location. A pre-established quantitative relationship is then used to estimate the damage based on the form of material volume loss. The proposed method is evaluated by 800 simulated test cases, showing an accuracy of around 90% for damage detection, location, and quantification. The method is further validated through modal data from a pipe with artificial damage, which provides a novel idea for baseline-free damage identification in pipes.