Topic: Nonlinear Dynamics and Control of Smooth/Non-smooth Mechanical/Mechatronic Systems

Jan Awrejcewicz

Lodz University of Technology

Abstract:   The talk is focused on research towards various applications of nonlinear dynamical systems theory to modeling, analysis, control and experimental investigations of mechanical/mechatronic oscillators. Three oscillating mechanical systems that are subjected to a magnetic field are presented. The first system consists of a single pendulum at the end of which a magnet is mounted. The coil located under the pendulum is powered by an alternating current, which forces the system to move. One-sided oscillating pendulum motion is investigated theoretically and experimentally. The carried out bifurcation analysis showed the existence of multi-period solutions as well as chaotic behaviours. The second object consists of the guide endowed with mass suspended in the air by the linear aerostatic bearing. Magnet-magnet and magnet-coil interactions have been investigated. The magnet-magnet interaction plays the role of the nonlinear magnetic spring while the magnet-coil interaction serves plays as the electromagnetic spring or electromagnetic damper in terms of the coil current signal. Static and dynamic characteristics of mechanical, magnetic and electromagnetic springs have been analysed. The third example deals with a universal multi-degree-of-freedom system equipped with linear rolling bearings. It is adapted to the study of vibrations of a two-degrees-of-freedom system with magnetic interactions. A mathematical model of the harmonically forced system is developed taking into account the non-linear magnetic elasticity generated by coaxially arranged cylindrical neodymium magnets. Numerical bifurcation analysis of the system is conducted, and experimental validation is performed obtaining a good agreement of both results. Period doubling cascades, chaotic attractors, hysteresis behaviour, amplitude jumps, quasi-periodic oscillations and wide multi-period windows are observed during the experiments, which will be illustrated and discussed during the talk. The fourth and fifth studied systems include control of flow induced vibration using parametric excitation and a bistable nonlinear energy sink, respectively. Finally, control of stick-slip vibrations in a disc brake model are addressed..

Biography:   Jan Awrejcewicz, from the beginning of his scientific career, was associated with the Faculty of Mechanical Engineering of the Lodz University of Technology. He became a full Professor in 1994 and in 1998 he founded and chaired the Department of Automation, Biomechanics and Mechatronics while in the years 1998-2022 he was the head of doctoral studies in Mechanics. In 2013-2017 he worked at the Warsaw University of Technology. He supervised 35 Ph.D. Theses. He is a real member of the Polish Academy of Sciences (2021-) and European Academy of Sciences and Arts (2021-).

He is the author/co-author of 58 monographs (including 30 in English), 2 textbooks and 1072 scientific articles (740 journals papers and 332 chapters in books). He was an editor of 36 books, editor of both 44 special issues of journals and 23 conference proceedings.

His scientific achievements include: analysis of dynamical systems using asymptotic and numerical methods (continuous and discrete systems), nonlinear dynamics of mechanical and mechatronic systems with friction and impacts, thermo-elasticity and tribology, as well as engineering biomechanics. His work focuses mainly on mechanical engineering/mechanics and applied mathematics. For his scientific achievements, he was twice honored with the prestigious Alexander von Humboldt Foundation award.

He served as a Keynote Speaker at 87 conferences and gave over 70 seminars at renowned universities abroad. Jan Awrejcewicz is also a Doctor Honoris Causa of 7 universities. In total, he worked for 10 years at renowned universities abroad, supported by the A. Humboldt Foundation, the Fulbright Foundation, the Japanese Science Promotion Society and Research Center for Advanced Science and Technology (Tokyo, Japan), and 3 French grants.

He was the organizer/chairman of 22 international conferences: ‘Dynamical Systems - Theory and Applications’ in Lodz, Poland (16; 1992-2021), ’International Conference of the Polish Society of Biomechanics’ in Lodz (2014), ‘Mechatronics: Ideas for Industrial Application’: Warsaw (2012), Lodz (2014), Gdansk (2015), ‘Biomechanics - Modeling, Numerical Simulations, Experimental Investigations and Biomedical Applications’, Lodz (1998), ’Nonlinearity, Bifurcation and Chaos. The Doors to Future’, Lodz-Dobieszkow (1996).

He is/was a member of 25 editorial committees of journals with IF and a member of over 70 editorial committees of other journals. He served as a member of the scientific committees of 226 conferences.

Topic: Large-Amplitude Nonlinear Vibration Response for Laminated Plates with Extensible Thickness

C.W.Lim

City University of Hong Kong

Abstract:   Laminated composites and structures have been widely used as the primary load-bearing elements in many engineering structures. In many circumstances, such load-carrying elements suffer from large-amplitude vibration when encountering external dynamic excitations. Therefore, a useful and efficient nonlinear model for nonlinear dynamic response is necessary for accuracy structural design. The classical plate theories often suffer from thickness locking due to the assumption of transverse inextensibility condition. To address this issue, the Deformation-based Unified Theory (DUT) recently established is extended to geometrically nonlinear vibration. DUT not only recognizes many classical plate theories as the different aspects of a single family, but also proposes new physical interpretations of those theories by introducing two new functions, thickness function and modified function, in the plate displacement field. The nonlinear von Kármán strain-displacement relation is adopted to capture geometric nonlinearity and accounts for transverse normal deformation to eliminate thickness locking without the need of any shear correction factor. Extensive numerical examples for various thickness functions and modified functions are presented to illustrate the large-amplitude nonlinear vibration response of thin and thick plates based on the new DUT theory. As a conclusion. the proposed model provides a computationally efficient and physically transparent model for nonlinear vibration analysis of large-amplitude composite thin-walled structures.

Biography:   Ir Professor Lim currently holds Changjiang Chair Professorship at Zhejiang University. He received a BEng from University of Technology of Malaysia, MEng and PhD from National University of Singapore and Nanyang Technological University, respectively. He was a post-doctoral at University of Queensland and University of Hong Kong, a professor at City University of Hong Kong (2000-2025), and a visiting professor at University of Western Sydney, University of Johannesburg, and University of Canterbury.

Professor Lim receives global recognition for original research in applied and computational mechanics. He was recently elected to European Academy of Sciences and Arts (2025), awarded the J.N. Reddy Medal 2020, published over 440 articles, H-index 73, and over 20,500 citations. He has co-authored one very well-selling title in Engineering Mechanics titled “Symplectic Elasticity”. As the first and corresponding author, he established one ground-breaking theory and the paper in JMPS has accumulated over 1,800 citations since first published in 2015. It is the most cited paper since 2004 in JMPS. His other work was granted the IJSS 2004-2008 most cited article award. He also published a research paper in Nature Communications. He was awarded Top Referees in 2009, Proc. A, The Royal Society.

Professor Lim was elected by secret votes to deliver a Plenary Lecture at WCCM (2022), the largest biennial meet for computational scientists. He holds the Chair of Selection Committee (2017-present) for J.S.Rao Medal in Vibration Engineering, GC member of IACM and APACM since 2019, Selection Committee Member of APACM awards, Vice Chair (2018-2020) and Chair (2020-2022) for ASCE/EMI Stability Committee, Vice Chair (2021-2023) and Chair (2023-2025) for ASME HK Section, and Technical Committee Member for IFToMM since 2011. He serves on over 20 journal editorial boards, notably JoMMS (Editor Board), JVET (Managing Editor), AMM (International Subject Editor), JSV (Subject Editor), RSOS (Engineering Subject Editor), etc.

Topic: Dynamics and Control of Smart Structures for Space Applications

Jinjun Shan

York University

Abstract:   Smart materials are materials that are capable of changing their properties in a controlled fashion, typically based on a supplied input. These types of materials can be incorporated into structures to create smart, or intelligent, structures capable of sensing and reacting to changes in their operating environment. A sensor is used to monitor the system and its output is connected to a control unit which will generate a response to the sensor signal, which is then applied to the actuator to generate a desired system behaviour. There are many forms of smart materials including shape memory alloys, piezoelectrics, magnetorheological and electrorheological fluids, and magenetostrictives and electrostrictives. The possibility to change a materials property in a controlled fashion is fascinating and has found applications in a diverse number of fields including positioning, shape and vibration control, and fault detection and mitigation. Within the space sector, as more is demanded of systems in increasingly complex applications in harsh environments, smart materials present themselves as one of the most viable solutions to these engineering problems. In this talk, Prof. Shan will provide a summary of his research on dynamics modeling and control system design of smart materials and structures, as well as their applications in active vibration control of flexible systems, active flatness control of space membrane structures, high-precision motion control, and high-spatial space spectrometer.

Biography:   Prof. Jinjun Shan is an internationally recognized expert in the areas of dynamics, control and navigation. He is a Full Professor of Space Engineering at the Department of Earth and Space Science and Engineering, York University. Prof. Shan received his Ph.D. degree from Harbin Institute of Technology, China, in 2002. His research progress is demonstrated through over 230 peer-reviewed journal and conference publications and 2 issued patents. Prof. Shan’s accomplishments in research and engineering education have seen him recognized with prestigious recognitions such as the Fellow of Canadian Academy of Engineering (CAE), the Fellow of Engineering Institute of Canada (EIC), the Fellow of American Astronautical Society (AAS), and a member of European Academy of Sciences and Arts (EASA). He serves the profession as the Associate Editor for several field-leading journals. He is the founding director of Spacecraft Dynamics Control and Navigation Laboratory (SDCNLab) at York University.

Topic: Advances in Non-smooth Dynamics: Theory and Applications

Marian Wiercigroch

Centre for Applied Dynamics Research, School of Engineering, University of Aberdeen, UK

Abstract:   Non-smooth dynamics represents the most vibrant area of nonlinear dynamics, where new fundamental and applied advances are continually being made. In this lecture, Professor Marian Wiercigroch will introduce recent breakthroughs in the field, with a special focus on non-smooth dynamical systems. As the newest and most rapidly developing sub-field, it encompasses novel phenomena such as grazing-induced bifurcations and maintains a broad range of applications across science and engineering.

In the first part of the presentation, Professor Wiercigroch will review the major advances in non-smooth dynamics over the last three decades, specifically highlighting the emergence of grazing and grazing-induced bifurcations. He will define the fundamental concepts and techniques essential to nonlinear dynamics, focusing specifically on the class of non-smooth dynamical systems. Furthermore, the lecture will demonstrate how these complex problems can be effectively modeled and analyzed using low-dimensional but calibrated dynamical systems. The generic complexity inherent in non-smooth dynamics will be illustrated through an elastic impact oscillator—an archetypal model used for the simulation of high-frequency vibro-impact drilling.

The second part of the discourse will be devoted to the concept of "Nonlinear Dynamics for Engineering Design." Professor Wiercigroch will present results from his recent projects, where nonlinear dynamic interactions have been strategically utilized to enhance the performance of real-world systems and structures.A significant emphasis will be placed on a major project within the energy industry: the development of a revolutionary downhole drilling technology. This technology has undergone rigorous testing in unique, specialized drilling laboratories. Professor Wiercigroch will argue that such engineering milestones would not be achievable without the foundation of calibrated low-dimensional models, bridging the gap between theoretical dynamics and practical application.

Biography:   Professor Marian Wiercigroch educated in Poland, US and UK holds a prestigious Sixth Century Chair in Applied Dynamics, and he is a founding director of the internationally renowned Centre for Applied Dynamics Research (CADR) at the University of Aberdeen.

His area of research is theoretical and experimental nonlinear dynamics, which he applies to various engineering problems. Wiercigroch has published extensively (over 600 journal and conference papers) and sits on a dozen editorial boards of peer review journals. He is a frequent keynote and plenary speaker at major international conferences and the Editor-In-Chief of International Journal of Mechanical Sciences, a leading journal in mechanics and mechanical engineering.

At Aberdeen he leads a large research group as the Director of CADR and in his career have supervised over 150 PhD students and postdoctoral researchers. He has hosted over 100 long term academic visitors from all over the world.

He is the inventor of new patented drilling technology called Resonance Enhanced Drilling and the Founder and Chief Technology Officer of a spinoff company iVDynamics Ltd. He has established in Aberdeen unique experimental laboratories allowing to investigate complex nonlinear dynamic interactions in mechanical systems with the focus on energy generation.

Marian is a Scottish Champion of Knowledge Exchange (2020) and served as a panelist in the Research Excellence Frameworks (2014, 2021), which assess the quality of research in the UK. He has received many awards and distinctions including a Senior Fulbright Scholarship (1994), Fellowship of the Royal Society of Edinburgh (2009), DSc honoris causa from the Lodz University of Technology (2013), Distinguished Honorary and Guest Professorships from the Perm National Research Polytechnic University (2017), Balseiro Institute (2018), Yanshan University (2021), University of Nottingham Ningbo (2023), Harbin Engineering University (2024), NUAA (2024), and Zhejiang University (2025). In 2025 he was elected a Fellow of the Royal Academy of Engineering and won China Friendship Award from Hebei Province.