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 is plates with bend shapes. This article 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 semicircular corrosion patches or 90-deg notches. The presence of notches affects stress distribution, necessitating thorough analysis to prevent accidents. Accordingly, this article focuses 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 semianalytical finite elements (SAFEs) with the finite element method (FEM). A bent plate section with various notch types is simulated using FEM, while SAFEs facilitate the definition of wave propagation through healthy regions of the plate. The study analyzes the scattering behavior 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, the aim of the article is to enhance the integrity assessment of structural components subject to such defects.