Ultrasonic Tomography for Corrosion Mapping and Crack Characterization
Date: 2019/12/11 - 2019/12/16
Academic Seminar: Ultrasonic Tomography for Corrosion Mapping and Crack Characterization
Speaker: Prof. Zheng Fan, Nanyang Technological University
Time: 02:30 p.m.- 03:30 p.m., Dec. 16th, 2019 (Monday)
Location: Room 454, Long Bin Building, UM-SJTU Joint Institute, Shanghai Jiao Tong University
Abstract
Detecting and quantifying damages in large structures is of growing interest in various industries. The information of defect size, e.g. length and height of cracks, size of the corrosion patch etc., can be further used in fracture mechanics to estimate the remaining service life of the component. Ultrasonic non-destructive evaluation techniques have been demonstrated to be useful for detecting and sizing defects that are embedded or growing from inaccessible surfaces. Ultrasonic defect characterization techniques can be broadly divided into four categories: temporal methods, amplitude methods, inversion methods and imaging methods. In this work, we use ultrasonic tomographic approach with array imaging technique to characterize corrosion damage using ultrasonic guided waves and crack with complex shapes using ultrasonic bulk waves. A numerical forward model is used to predict the scattering of ultrasonic waves 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. In this talk, recent progress in the research of feature guided waves, acoustic metamaterial and laser ultrasound will also be shared.
Biography
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 (NTU) 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 very strong linkage to industry globally, including Rolls-Royce, Shell, Lloyds Register, EDF, Sembcorp, etc. As one of the leaders in the research of SHM/NDE in Singapore, Prof Fan has secured more than 7 million Singapore dollars research funding as Principle Investigator since he joined NTU.
Prof Fan’s research activity covers from in-depth investigation of fundamental theories to applied science for real-world problems. The outcome of the research has been published a few prestigious journals such as Nature Communications, Applied Physics Letters, Proceeds of Royal Society A, Composite Science and Technology, Smart Materials and Structures, etc. In recognition of his outstanding contribution in SHM, he was awarded the Achenbach metal in 2018. He serves as an Associate Editor to “Ultrasonics” – one of the top-tier journal published by Elsevier in this field.