Lamb Wave Based Experimental and Finite Element Simulation Studies for Damage Detection in an Aluminium and a Composite Plate using Geodesic Algorithm

The present research focuses on localizing structural damages in an aluminium and a woven fabric composite laminate. Finite Element (FE) and experimental simulation studies are carried out on specimens of these plates with and without damages, and the response data are collected at various sensor locations. Piezoelectric wafer (PW) transducers are used for actuation and reception of Lamb wave. The group velocity dispersion curves obtained through the experiment and simulation are compared with those obtained analytically to ensure effective actuation and sensing of Lamb wave. A Continuous Wavelet Transform (CWT) is used for receiving the arrival times of the wave reflected from the damages to the sensor locations. After acquiring arrival time data, the geodesic algorithm is employed to locate the damage in the specimens. The geodesic algorithm used is a two-step strategy initially using the Pythagorean Theorem to find the discrete geodesics in the structure, using mesh information and followed by locating the intersections of these geodesics to get the damage locations. Herein, the geodesic algorithm is shown to be effective in detecting several damages in a plate, both experimentally and through FE simulation.