Fu-Kuo Chang
Structures and Composites Laboratory
Dept. of Aeronautics and Astronautics
Stanford University
Plenary Title: Are We Ready for Continuous Structural Health Monitoring (SHM) for Aircraft?
Abstract: Real-time structural health monitoring (SHM) using onboard sensors has the potential to revolutionize aircraft maintenance and operations by enabling continuous damage inspection and state monitoring during flight. This approach could transform how we maintain and operate aircraft, providing enhanced situational awareness, particularly in unexpected conditions where timely and precise control is crucial to preventing failure. However, damage inspection and state monitoring operate on different timescales and require varying levels of sensitivity from sensor data. In this presentation, we will review recent advancements in SHM based on Acousto-Ultrasound techniques, utilizing onboard piezoelectric sensor and actuator networks for aircraft applications. Additionally, we will explore the integration of artificial intelligence (AI) and machine learning (ML) with SHM to enable continuous monitoring. Finally, we will discuss the challenges associated with implementing SHM solutions in real-world aircraft operations.
Biography: Dr. Fu-Kuo Chang is a Professor in the Department of Aeronautics and Astronautics at Stanford University. His primary research interest is in the areas of multi-functional materials and intelligent structures with particular emphases on structural health monitoring, self-sensing diagnostics, intelligent sensor networks, and multifunctional energy storage composites for transportation vehicles as well safety-critical assets. He is a recipient of the SHM Lifetime Achievement Award (2004), SPIE NDE Lifetime Achievement Award (2010), and the PHM lifetime Achievement Award (2018). He is the Editor-in-Chief of Int. J. of Structural Health Monitoring. He is also a Fellow of AIAA and ASME.
Alain Lhémery
Université Paris-Saclay, CEA-LIST, France
Plenary Title: A Review of Models Developed at CEA for Simulating Guided Wave NDE/SHM Methods with a Focus on the Modal Approach
Biography: Alain Lhémery (BSc in physics, 1984 - MSc in acoustics, 1986 - PhD in acoustics, 1990 - HDR in physics, 2000) is a Fellow of the CEA (French Atomic and Alternative Energies Commission) and Director of Research at Paris-Saclay Univ. His work [at École Centrale Paris as a PhD student (1986-90) and assistant professor (1991-5), at City University London as Honorary Visiting Fellow (1990-1) and since joining the CEA (1995-...)] focuses on the modeling and simulation of the transduction, propagation and scattering of ultrasonic waves (bulk or guided), for applications in NDE and SHM. Part of this work is implemented in the NDE simulation platform CIVA. To date, he has supervised 22 PhD students to completion. He has taught and continues to teach general and ultrasonic NDE to graduate students at engineering schools (CentraleSupélec, ENSTA) and universities (Univ. Paris-Saclay, Sorbonne Univ., Univ. Évry, Le Mans Univ.). In 2001 he founded the annual series Anglo-French Physical Acoustics Conference with Pr. N. Saffari (UCL). He serves as subject editor for NDT&E International since 2016 (thermal, ultrasonic and emerging techniques).
Abstract: Our aim is to review a set of models (and examples of their applications) developed over the last two decades at the French Atomic Energy and Alternative Energies Commission (CEA), most being implemented as tools in the CIVA software platform for simulating NDE/SHM methods based on elastic guided waves (GW).
Two types of modeling approach are being developed at CEA, whether for simulating bulk wave (BW) or GW ultrasonic inspections. One is modal: waves are described assuming they propagate as modes whose contributions add up linearly; CIVA models are transient for BW and harmonic followed by Fourier synthesis to predict signals for GW. The other is numerical, based on time-dependent finite elements; this approach makes it possible to deal with all configurations of ultrasonic inspection without the need for making assumptions about the nature of the propagating waves. In GW simulation, one cannot imagine solutions involving more different computations than those involved in these two approaches. Comparing their predictions is an excellent and safe way of cross- validating them. However, given the known advantages and disadvantages of each of these approaches, a third is also developed, which consists of trying to take advantage of the best of both by hybridizing them.
The presentation will focus on models developed within the modal semi-analytical approach and their hybridization with local numerical computations. Time allotted will allow us to briefly describe how the models work, and to illustrate with a few examples of application what can be studied with them.
Zheng Fan
School of Mechanical and Aerospace Engineering
Nanyang Technological University, Singapore
Plenary Title: Ultrasonic Inspection and Characterization in Materials with Complex Properties
Abstract: Ultrasound technology offers immense potential across various disciplines, primarily due to two fundamental aspects: its capacity to convey information about the medium it traverses and its ability to transfer mechanical energy into other forms. Ultrasonic waves, when propagated through a medium, interact with its constituents, modifying the wave in ways that can be measured. These modifications carry detailed information about the medium's properties, including the presence, size, and nature of scatterers. By analyzing the changes in the wave's speed, amplitude, and frequency after it has passed through the medium, it's possible to infer the medium's characteristics. Our focus includes advanced imaging methods that combine numerical models for predicting wave interactions with defects and iterative modeling to reconstruct defect profiles accurately. This innovative approach is key for monitoring defect development over time, aiding in the accurate prediction of structural service life. Meanwhile, recent advancements in manufacturing techniques, such as additive manufacturing, have generated a strong demand for non-destructive characterization of material properties. It is known that material properties are influenced by microstructure factors, including morphology, texture, grain size, etc. Since these factors also affect the propagation of ultrasonic waves, it is possible to characterize the microstructure using ultrasound. I'll share ongoing research on correlating microstructural features in polycrystals with ultrasonic properties, highlighting their potential for material characterization. Additionally, I'll explore the application of ultrasonic characterization techniques to evaluate the state of health (SOH) and state of charge (SOC) of electric vehicle (EV) battery cells, and perform temperature mapping within battery components. By integrating ultrasonic insights into the EV battery domain, we aim to enhance our understanding of their performance and longevity, offering valuable insights for the growing electric vehicle industry.
Biography: Dr. Zheng Fan is an associate professor in the School of Mechanical and Aerospace Engineering at Nanyang Technological University, Singapore. He earned his Ph.D. degree in Mechanical Engineering from Imperial College London in 2010, and his Bachelor's and Master's degrees in Acoustics from Nanjing University in 2004 and 2006, respectively. Currently, he leads a research team dedicated to developing novel techniques for the non-destructive evaluation, structural health monitoring, and sound manipulation. His work integrates advanced physics and modeling techniques with the development of technologies that can be rapidly deployed in practical settings. Dr. Fan maintains strong links with the global industry, collaborating with major companies such as Rolls-Royce, Shell, Lloyd's Register, EDF, and Sembcorp, etc. His research spans from thorough investigations of fundamental theories to the application of science in addressing real-world challenges. The results of his work have been published in over 90 papers in top tier journals. He holds two international patents and has successfully licensed these technologies to industry partners. In 2018, Dr. Fan was awarded the Achenbach Medal for his outstanding contributions to structural health monitoring. Since 2020, he has been ranked among the world's top 2% of scientists by Stanford University. Dr. Fan also serves as an Associate Editor for "Structural Health Monitoring – An International Journal" and "Ultrasonics," two leading journals in his field.