Effect of Various Notch Shapes on Lamb Wave Scattering Behavior in a Bent Plate

Abstract

The application of guided waves to investigate commonly used plate shapes in the aerospace, mechanical and civil industries are plates with bend shapes. This paper investigates the interaction of fundamental Lamb waves with notches in bent plates, commonly found in aerospace, mechanical, and civil engineering applications. These areas are particularly susceptible to failure due to defects such as cracks and notches, which often manifest as semi-circular corrosion patches or 900 notches. The presence of notches affects stress distribution, necessitating thorough analysis to prevent accidents. Accordingly, this paper focus on the interaction of fundamental Lamb waves through two types of notches that could be present inside a bent metal plate section. To explore this, a hybrid numerical framework is employed which combines Semi-Analytical Finite Elements (SAFE) with the Finite Element Method (FEM). A bent plate sections with various notch types is simulated using FEM, while SAFEs facilitate the definition of wave propagation through healthy regions of the plate. The study analyses the scattering behaviour of Lamb waves for different notch configurations and examines both fundamental modes over a specified frequency range. With a change in the interrogation signal parameters, there is a noticeable difference in the sensitivity of scattered waves with different notch types. Formulating a strategy for identifying and locating a notch inside a bent plate may need careful consideration of the important conclusions drawn. Understanding these interactions, aim of the paper is to enhance the integrity assessment of structural components subject to such defects.