Fatigue crack detection in edges of thin-walled structures with corners using the fundamental mode of edge waves

Abstract

Non-destructive detection and evaluation of fatigue cracks is critical to maintain safety and effective operation of high-value assets working under cyclic loading. However, this can be difficult in the case of the corners of the structural elements, especially at inaccessible locations. In this article, the propagation of the fundamental symmetric mode of edge wave (ES0) along structural features such as sharp and rounded corners are investigated using experimental and numerical methods. The ultimate aim of this study is to demonstrate that the ES0 is a promising for defect detection in geometries with corners. The outcomes of this study show that ES0 wave is able to propagate through sharp and rounded corners and provides a way to inspect difficult-to-reach locations. Further, the numerical simulations indicate that the radius-to-wavelength ratio above 3 has no significant impact on the wave amplitude when the ES0 propagates through the rounded corner. The results also demonstrate that the presence of fatigue crack leads to generation of the second harmonic of the ES0 wave mode, and this phenomenon can be utilised in the development of fatigue crack detection and characterization procedures.