Influence of Lamb Wave and Structural Parameters on Damage Localization: A Comprehensive Analysis Using Numerical Simulations

Abstract

The structural health monitoring (SHM) field extensively uses Lamb waves for defect detection due to their extended propagation capability and sensitivity to various damage types. However, the Lamb wave exhibits a few limitations caused by its multimode characteristics and intrinsic dispersion behaviour. It is challenging to localize structural defects due to the presence of many dispersive modes at a particular frequency band. Varying the central frequency of a Lamb wave across its dispersion curve range for a specific structural thickness is investigatedhere to study its behaviour in damage localization. Numerical simulations using the finite element method in three dimensions show fifteen aluminium plate analyses in the time domain. A throughthickness hole is created as a defect in the plate. The least dispersed symmetric Lamb mode (S0) with an increasing central frequency in the specified range is actuated in each scenario. The output of out-of-plane signals is utilized in damage location imaging. Lamb wave frequency accuracy varies significantly, as seen in the images of the damage areas. The damage area grows as the central frequency of the actuation signal increases. The precise location is estimated in each of the fifteen cases; however, the projected damage zone differs. According to the imaging study, damage localization is improved using low-frequency Lamb modes.