Structural Health Monitoring in Cylindrical Structures Using Helical Guided Wave Propagation

Abstract

Defect detection and characterization are critical tasks for structural health monitoring of pipe-like engineering structures. Propagation and detection of ultrasonic helical Lamb waves using macro fiber composite (MFC) sensors is studied. Experiments for defect detection and characterization on an aluminum hollow cylinder (114mm in outer-diameter and 6mm of wall thickness) were carried out. An experimental setup using MFC sensors coupled to the cylinder's surface in a pitch-catch configuration is presented. Time-frequency representation (TFR) using wavelets is employed to accurately perform mode identification of the ultrasonic captured signals. The initial results indicate that the use of helical waves could allow the monitoring of damage in difficult to access critical areas by locating the sensors only on a small region of the periphery of the cylindrical structure under inspection.