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

Hankai Zhu; Ching Tai Ng; Andrei Kotousov

doi:10.1016/j.ultras.2023.106995

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

Ultrasonics. 2023 Jul:132:106995. doi: 10.1016/j.ultras.2023.106995. Epub 2023 Mar 27.

Authors

Hankai Zhu¹, Ching Tai Ng², Andrei Kotousov³

Affiliations

¹ School of Architecture and Civil Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
² School of Architecture and Civil Engineering, The University of Adelaide, Adelaide, SA 5005, Australia. Electronic address: alex.ng@adelaide.edu.au.
³ School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.

PMID: 37003207
DOI: 10.1016/j.ultras.2023.106995

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.

Keywords: Edge wave; Fatigue crack location; NDE; Nonlinear guided wave; Rounded corners; Sharp corners.