Dr. Weidong Zhu, Professor, University of Maryland, Baltimore County, USA

Biography: Weidong Zhu is a Professor in the Department of Mechanical Engineering at the University of Maryland, Baltimore County, and the founder and director of its Dynamic Systems and Vibrations Laboratory and Laser Vibrometry and Optical Measurement Laboratory. He received his double major BS degree in Mechanical Engineering and Computational Science from Shanghai Jiao Tong University in 1986, and his MS and PhD degrees in Mechanical Engineering from Arizona State University and the University of California at Berkeley in 1988 and 1994, respectively. He is a recipient of the 2004 National Science Foundation CAREER Award. He has been an ASME Fellow since 2010, and has served as an Associate Editor of the ASME Journal of Vibration and Acoustics and the ASME Journal of Dynamic Systems, Measurement, and Control, and as a Subject Editor of the Journal of Sound and Vibration and Nonlinear Dynamics. His research spans the fields of dynamics, vibration, control, applied mechanics, metamaterials, structural health monitoring, and wind energy, and involves analytical development, numerical simulation, experimental validation, and industrial application. He has published 277 SCI-indexed journal papers in these areas and holds seven U.S. patents. He is a recipient of the 2020 University System of Maryland Board of Regents Faculty Award for Excellence in Research.  

Speech Title: Dynamics of Continuous Systems: From Time-Varying, Nonlinear, and Flexible Multibody Systems to Phononic Structures

Abstract: Some interesting results on the dynamics of continuous systems are reviewed. They involve: 1) dynamic stability of translating media with time-varying lengths and/or velocities; 2) nonlinear vibrations of systems with large degrees of freedom and general nonlinearities; 3) new spatial discretization methods for one- and two-dimensional continuous systems; 4) new formulations of flexible multibody dynamics with application to elevator traveling cables; and 5) elastic wave propagation in strongly nonlinear phononic structures. Two types of dynamic stability problems are addressed from the energy viewpoint in the first area: dynamic stability of translating media during extension and retraction with application to elevator hoist cables, and parametric instabilities in second-order nondispersive continuous systems with periodically varying lengths and/or velocities. The incremental harmonic balance method is used in the second area to handle periodic responses of high-dimensional models of nonlinear continuous systems and rigid multibody systems, and their stability and bifurcations, as well as their quasi-periodic responses. New spatial discretization methods in the third area ensures that all boundary conditions of continuous systems are satisfied and hence uniform convergence of solutions. New nonlinear models of slack cables with bending stiffness and arbitrarily moving ends are developed for moving elevator traveling cables with large deformations in the fourth area. A minimal number of degrees of freedom are needed to achieve the same accuracy as that of the finite element method. Wave propagation analyses of strongly nonlinear continuous and discrete systems are developed using the wavelet finite element method and incremental harmonic balance method, respectively, in the fifth area to study influences of nonlinearities on wave propagation characteristics. Some experimental results are presented to validate theoretical predictions. 

Dr. Ji Wang, Professor, Ningbo University, China

Biography: Professor Ji Wang has been a Qianjiang Fellow Professor of Zhejiang Province at Ningbo University since 2002.  He also served as Associate Dean for Research and Graduate, School of Mechanical Engineering and Mechanics, Ningbo University, from 2013 to 2019.  Professor Ji Wang is the founding director of the Piezoelectric Device Laboratory, which is a designated Key Laboratory of the City of Ningbo.  Professor Ji Wang was employed at SaRonix, Menlo Park, CA, as a senior engineer from 2001 to 2002; NetFront Communications, Sunnyvale, CA, as a senior engineer and manager from 1999 to 2001; Epson Palo Alto Laboratory, Palo Alto, CA, as Senior Member of Technical Staff from 1995 to 1999.  Professor Ji Wang also held visiting positions at Chiba University, University of Nebraska-Lincoln, and Argonne National Laboratory.  He received his PhD and Master’s degrees from Princeton University in 1996 and 1993 and his bachelor’s from the Gansu University of Technology in 1983. 
Professor Wang has been working on acoustic waves and high-frequency vibrations of elastic and piezoelectric solids for resonator design and analysis with several US and Chinese patents, over 200 journal papers, and frequent invited, keynote, and plenary presentations at major conferences around the world.  He has been a board member, advisor, and consultant to many leading companies in the acoustic wave device industry.  Professor Wang has been a member of many international conference committees and currently serving the IEEE UFFC Technical Program Committees of the Frequency Control and Ultrasonics Symposia, the IEEE MTT-S, and the IEC TC-49.  He is also the founding chair of the Committee on Mechanics of Electronic and Magnetic Devices, CSTAM, and the SPAWDA.  Profess Wang was the editor-in-chief of Structural Longevity and a member of editorial boards of several international journals.

Speech Title: A Quantitative Characterization and Assessment of Surface Roughness of Components from the Measurement of Wave Velocities

Abstract: The surface of materials of commonly used components of various functions is processed with many technologies and subjected to change under the attack of many factors in service such as corrosion, friction, and impact.  With safety and reliability concerns, it is always beneficial to have the surface and immediate vicinity characterized with the use of mechanical properties and other factors such as bonding rigidity and surface roughness.  Among many techniques for the measurement and assessment, methods based on nondestructive testing technology such as acoustic waves are always preferred for the advantages such as in-situ, fast, and noncontact features.  To improve such measurement, we consider a component with a rougher surface for the acoustic wave properties about changes in material properties.  By calculating the velocity of surface acoustic waves with the consideration of material properties and surface roughness, more accurate properties of the surface layer are obtained to enable accurate estimation as part of the characterization and assessment procedure.  Further improvement will be the consideration of the grading materials.  It is believed such analysis will lead to possible novel approaches for the assessment of the surface of components of various functions.  Such a method can be used for the measurement of the visible and nonvisible material surface with known properties for an enhanced assessment of the component to satisfy engineering applications’ needs.

Dr. Junjie Zeng, Professor, Guangdong University of Technology, China

Biography: Dr. Junjie Zeng is currently a Professor in Structural Engineering and Associate Head of the Department of Civil Engineering at Guangdong University of Technology, China. He received a Ph.D. in Structural Engineering from The Hong Kong Polytechnic University. He is an active researcher in field of high-performance materials and structures (e.g. fiber-reinforced polymer composites, ultra-high performance concrete, floating structures). Dr. Zeng has published over 70 SCI indexed journal papers. Dr. Zeng has received a number of research grants, including an ARC Discovery Early Career Researcher Award and two NSFC funds. He is on the 2021 World's Top 2% Scientists List of Stanford University.  

Speech Title: Novel FRP-UHPC Tubular Structural Members

Abstract: A series of novel forms of tubular members made of prefabricated ultra-high-performance concrete (UHPC) internally reinforced with fiber-reinforced polymer (FRP) grid (referred to as “FRP-UHPC tubular members”) are developed. FRP-UHPC tubular members have excellent mechanical properties, and their excellent performances are demonstrated through three preliminary studies: i) flexural behavior FRP-UHPC plates; ii) flexural behavior of FRP-UHPC tubular beams; iii) compressive behavior of FRP-UHPC tubular columns; iv) punch shear behavior of FRP-UHPC plates. A novel connection system between two prefabricated FRP-UHPC plates is also proposed. The proposed FRP-UHPC tubular members are attractive in various marine constructions (e.g. floating structures).

Dr. Guohua Xie, Associate Professor, Wuhan University, China

Biography: Dr. Guohua Xie obtained his Ph.D. degree from Jilin University (China) in 2011, working on OLED microdisplays. From August 2011, Dr. Xie carried out his postdoctoral research at TU Dresden (Germany), sponsored by Alexander von Humboldt Foundation, investigating the stability of OLEDs. From January 2013 to January 2015, Dr. Xie worked for an OLED-based interdisciplinary project of structured light beams from OLEDs at the Organic Semiconductor Center of the University of St Andrews (UK). Since January 2015, he has been serving as an associate professor at the College of Chemistry and Molecular Sciences of Wuhan University (China), focusing on the interdisciplinary research of solution-processed organic optoelectronic materials and devices. Dr. Xie has co-authored over 200 peer-reviewed publications with an H-index of 46 and contributed to three edited book chapters on organic optoelectronics. In 2020, Dr. Xie has been admitted as a Fellow of Royal Society of Chemistry. Currently, Dr. Xie is a guest editor respectively for “Frontiers in Chemistry”, “Molecules” and “International Journal of Molecular Sciences”. Meanwhile, he also serves as a member of Youth Editorial Board respectively for “Chinese Journal of Luminescence”, “SmartMat” and “The Innovation”.

Speech Title: Solution-Processed Organic Light-Emitting Devices

Abstract: Organic light-emitting devices (OLEDs) have many promising applications in active matrix displays, solid-state lighting, visible light communication, and medical treatment, which make them attractive in fundamental and applied researches. Currently, the manufacture of OLEDs mainly relies on high-vacuum thermal evaporation, which is highly expensive and complicated. To address this issue, solution-processed OLEDs are favorable due to the merits of large-area and low-cost. In this talk, the state-of-the-art spin-coated OLEDs will be presented and explained, including material selection and device engineering. In addition, the innovative technologies of transfer printing and inkjet printing for solution-processed OLEDs will be elaborated, respectively, which are more competitive for large-area mass production.

Dr. Mohammadreza Vafaei, Associate Professor, Universiti Teknologi Malaysia (UTM), Johor, Malaysia

Biography: Mohammadreza Vafaei (PhD, P.Eng., M.ASCE, M.EERI) is currently an associate professor in the school of civil engineering, Universiti Teknologi Malaysia (UTM), Johor, Malaysia. Before joining UTM, he served many consulting companies and has led the seismic design of many structures like tall buildings, air traffic control towers, airport terminals, water reservoirs, telecommunication towers, and monumental structures. His expertise includes seismic design and retrofitting of structures, vibration control through passive dampers, and structural health monitoring. He has been invited as the keynote speaker for several international conferences and workshops. He has patented several inventive produced and published more than 60 papers in referred journals and conferences. Dr. Vafaei also has been awarded more than 10 international and national research funds and has won several gold and silver medals for his innovative products from international exhibitions.  

Speech Title: Seismic Health Monitoring of Structures through Sensor Clustering and Artificial Neural Networks

Abstract: After strong earthquakes it is important to distinguish quickly the damaged structures from those that can be occupied to reduce the post-earthquake problems. For many years, this task has been achieved by experienced engineers through visual inspections. Although the seismic vulnerability assessment through visual inspections has been well established in different codes, it is a time consuming approach and its result depends on the experience of engineers. Therefore, in recent decades, great efforts have been made to develop new techniques that can identify seismic-induced damage with high accuracy and in real-time automatically. To this end, important structures like tall buildings and long-span bridges are equipped with different sensors to collect data during seismic excitations. These data are then analyzed to extract some important features that can detect the presence of damage, localize it, and estimate its severity. In this talk, at first the background of damage identification through the use of neural networks are explained and the advantages and disadvantage of such techniques are discussed. Then, a novel approach is proposed for damage identification under seismic excitation. The proposed method make use of response accelerations, a sensor clustering method, and neural networks. The proposed algorithm is applied to the validated finite element model of Kuala Lumpur international airport air traffic control (ATC) tower. The efficiency of the proposed method in damage identification is demonstrated by comparing the results of nonlinear time history analysis and those predicted by trained neural networks. 

The Keynot Speaker list above is continuously updated.