Scattering of the fundamental anti-symmetric Lamb wave at through-thickness notches in isotropic plates

Abstract

Lamb wave based structural health monitoring technique is one of the promising techniques for detecting damage in structures. Among different types of guided waves, the fundamental anti-symmetric mode of Lamb wave (A0) has attracted considerable attention for damage detection in plates due to its outstanding properties, such as sensitivity to small and different types of defects, which make it a powerful tool for damage detection. Cracks are one of the major culprits in metallic structures which affect their durability and serviceability. Once the crack appears on the structures, it can affect its serviceability. It is important to detect cracks at early stage to avoid any catastrophic failure of the structures. This paper presents a study on the capability of using the A0 Lamb wave in detecting crack-like defects in aluminium plates, in which the scattering behaviour of the A0 Lamb wave at through-thickness notches in aluminium plates is studied in detail. 3D explicit finite element simulations are used to provide a comprehensive study on the scattering characteristics of the A0 Lamb wave at notches with different sizes and orientations. This study also considers different incident and scattered wave directions on the scattering characteristics. The results show that scattering characteristics of the A0 Lamb wave are sensitive to the size and orientation of notches. The findings of this study can improve the understanding of the capability of the A0 Lamb wave in detecting the crack-like defects and further advance damage detection techniques.