Keynotes

Rainer Nordmann (born 1943), studied Mechanical Engineering, followed by a PhD research work about Eigenvalues in Rotating Machinery . During his subsequent university career at two German Universities in Kaiserslautern and Darmstadt he was mainly involved in research projects in Rotordynamics, Vibration control of machines and mechatronics. In these disciplines he has supervised about 100 PhD-Students and has published more than 100 papers in international journals and conference proceedings.

He is co-author of the books Rotordynamik (in German), Magnetic Bearings and Vibrations of Power Plant Machines. Together with two colleagues he founded 1991 the nowadays called SIRM - European Conference on Rotordynamics. From 1995 until 2008 he was a consult for TVO (Finland) in order to solve vibration problems of turbogenerators in power plants.

After his retirement Rainer Nordmann worked from 2009 to 2012 as manager for Rotordynamics in the international R&D center of Alstom Power in Baden (Switzerland) and from 2013 to 2025 as a consult for the Fraunhofer Institute LBF and for other companies in vibration control and mechatronics. From 2009 until 2016 he was chairman of the ISO working group “Rotordynamics and Vibrations of Machines” and from 2006 until 2011 chairman of the IFToMM Technical Committee

Future Challenges in Rotordynamics

There is a large variety of Rotating Machinery in modern industry and everyday life. For the designer of such machines besides the required machine function other aspects like availability, reliability, safety and machinery life time are of importance. Due to this fact a detailed Rotordynamic analysis has to be an essential part in the design process, to avoid irreversible damages, malfunctions and a rapid fatigue of components. Investigations of vibrations in Rotating Machinery are based on the disciplines of mechanics, solid and fluid dynamics, electromechanics and nowadays more and more by mechatronics and digital techniques. With the three tools of Theoretical Modelling, Numerical Analysis and Experimental Analysis (Testing) different tasks in Rotordynamics can be solved. New methods and technologies have been further improved in the past and help design engineers as well as test engineers to realize accepted vibrations of Rotaing Machinery. However, due to the existing world wide transformation processes new challenging tasks in different engineering areas have to be solved. With respect to Rotordynamics different positive effects can be achieved when vibrations are more reduced. Lower vibration levels would for example lead to:

• a reduction of mechanical stresses and fatigue,
• higher efficiencies due to tighter clearances in bearings and seals,
• a reduction of disturbances due to acoustical emissions
• an improvement of work piece qualities in production processes.

Some time ago a workgroup of researchers from the IFToMM Technical Committee identified topics of recent advances in Rotordynamics and pointed out the future challenges for science and technology. All of these topics can be grouped in one of the four future challenges:

• development of active and passive hardware components
• Theoretical Modeling, including interactions with other disciplines
• improved procedures in Numerical Analysis
• new Experimental Analysis and Testing methods

In this lecture some of the future challenges in Rotordynamics will be presented. Realized examples in this direction will be discussed

• development of passive gas foil bearings
• torsional vibrations due to electromechanical interactions
• vibration reduction by means of active balancing devices
• active damping with magnetic bearings and piezo actuators
• monitoring and failure diagnosis by means of digital twins

Dr. Rajiv Tiwari is currently Professor in the Department of Mechanical Engineering, Indian Institute of Technology Guwahati, where he has been working since 1997. He completed his PhD from IIT Kanpur in the area of Rotor Dynamics in 1997. Just after PhD, he worked in Regional Engineering College, Hamirpur (Himachal Pradesh), India for a year during 1996- 1997. He worked as Research Officer for one year in 2001 in University of Wales, Swansea, UK and as DAAD Fellow in Technical University of Darmstadt Germany in 2011 for two months. Dr Rajiv Tiwari works in the area of Rotordynamics and Design of Rolling Bearings. He has more than 250 papers in international and national journals and conferences. He has successfully organised number of national and international conferences and short terms courses in the area of vibrations and rotordynamics. He has authored two book (i) Rotor Systems from CRC Press, USA in 2017 and Simple Rotor Analysis through Tutorial Problems from CRC Press, USA in 2023. He has developed web and video-based courses under NPTEL on Mechanical Vibration and Rotor Dynamics. He has been offering consultancy for last several years to Indian industries, like Indian Space Research Organization (ISRO), Trivandrum; Combat Vehicle R&D Establishment (CVRDE) Chennai; Tata Bearings, Kharagpur; Gas Turbine Research Establishment (GTRE), Bangalore, NBC Bearings; apart from other local industries in the northeast of India. Prof. Tiwari has been featured consecutively for last five years among World’s Top 2% Influential Scientists List created by Stanford University. He is Associate Editor to the Journal of Vibration and Control (JVC), Sage Publications, and Journal of Vibration Engineering and Technology (JVET), Springer Nature Publications. Also, he is in Worldwide Technical Committee on Rotor Dynamics of International Federation of Machines and Mechanisms (IFToMM). In 2022, he has been interviewed by magazine Tribology & Lubrication Technology, USA for its cover story on Artificial Intelligence for Real-World Mechanical Systems. Recently, he has been included in The Bearings Sectional Committee, PGD 13, of Bureau of Indian Standards (BIS), which is responsible for the development of the national and international standards on the ‘Magnetic Bearings’, 'Aerospace Bearings' and 'Railway Bearings’.

Fault Detection and Diagnostics in Rotating Machinery using Machine Learning

Due to tremendous increase in the computation power, advances in the sensor technology and development in machine learning algorithms, it is now possible to collect enormous valuable information from high-speed mechanical and electrical rotating machinery, process them very fast to extract useful features, and train machine learning algorithms to be useful for the fault detection and its diagnostics. The present keynote presentation briefs research work done at IIT Guwahati in this field for the past more than two decades on variety of rotating machinery, e.g. rolling bearings, gearbox, geared-rotor, centrifugal pumps, induction motor, etc. It covers brief induction to machine learning algorithm, for example, support vector machines, data collections (vibration, pressure, current, etc.), feature extraction from data, feature selection, training to machine leaning algorithms, and finally testing. Latest trends on integrating physical based model with ML based model (hybrid model) will also be briefed. Potential application of the methodology for the practical application will also be addressed.