Screening and Tomographic Reconstruction of Defects by Structural Guided Ultrasonic Waves

Detecting and quantifying damages in large structures is of growing interest in various industries. Conventional ultrasonic methods are tedious and expensive, especially for inaccessible areas. Ultrasonic structural guided wave offers an attractive alternative for the rapid inspection of defects from a remote position in a large structure. In this talk, two interesting applications of ultrasonic guide waves will be discussed: defect screening in structural features such as weld, stiffeners and bends, as well as defect characterization using guided wave tomographic approach. A numerical forward model is used to predict the scattering of guided wave through defects, and an iterative inverse model is developed to reconstruct the defect profile. The imaging algorithm allows higher order diffraction and scattering to be considered in its numerical solver, thus can provide accurate inversion results. Despite two guided wave applications, recent progress in the research of acoustic metamaterial for NDE and laser ultrasound will also be shared in the talk.  

Zheng Fan—School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798

Prof Zheng Fan obtained his PhD degree at Imperial College London, specialized in ultrasonic Non-Destructive Evaluation (NDE). He is currently an assistant professor in the school of Mechanical and Aerospace Engineering at Nanyang Technological University in Singapore, leading a research team to develop novel techniques for metal and composite inspection, structural health monitoring and material characterization, by integrating physics and modeling techniques with the development of rapidly exploitable technologies.  He has collaborated with varies industries including Rolls-Royce, Shell, Lloyds Register, Sembcorp etc for different research and consultancy projects. He is a recipient of the Achenbach metal in 2018 for his outstanding contribution in SHM. He serves as an Associate Editor to “Ultrasonics” – one of the top-tier journal published by Elsevier in this field.

zfan@ntu.edu.sg