NEW PERSPECTIVES IN SOUND AND VIBRATION RESEARCH AND DEVELOPMENT FOLLOWING FROM STOCHASTIC RESONANCE PHENOMENON

Jiri Naprstek
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Jiří Náprstek graduated from the Faculty of Civil Engineering of the Czech Technical University in 1966 (Eng), oriented to Theoretical and Applied Mechanics od structures. His post-graduate study in ITAM CAS, 1968 - 1972 were completed in 1972 (PhD.). In 1997 he was awarded the title Doctor of Sciences (DSc.). Later he became CENG and FENG. He is a senior scientist at the Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences.
His research activities are oriented predominantly to various aspects of Nonlinear Dynamics with a focus on Basic research (Rational or Analytical Dynamics, Stochastic Mechanics, Computational Mechanics) and Applied research (Dynamics of civil and mechanical engineering systems and continua, Earthquake / Wind / Railway engineering, Industrial problems).
He is an author of more than 390 original articles in international scientific periodicals and prestigious conference proceedings, 8 monographs (co-author), 89 research and expert reports, editor of 4 proceedings of international conferences, 8 proceedings of national conferences. The book: Náprstek, J. et al. (eds): Vibration Problems –ICOVP 2011, Springer, Berlin, Heidelberg, 2011, 680 pgs., became Springer's bestseller – more than 20.000 copies in period 2011-2017.
He is a member of the editorial board and reviewer of many international journals (Elsevier, Springer, Wiley, Taylor-Francis, etc.) and member or chairman of a number of international special committees in Czech Republic, Italy, Belgium, Hong-Kong, Macau and other countries (PhD. and professorial examining boards, Ministry Commissions, Grant agencies and Scientific Foundations). He works in many councils of international scientific societies (IUTAM, EUROMECH, IFTOMM, EAHE, EASD, IAWE, EAEE, ICOVP, COMPDYN, etc.) and organized many mini-symposia on Nonlinear Dynamics at international conferences.
He has been awarded by many Prizes and Medals, among others: Prize of the Czech Academy of Sciences (CAS) 2018, Special Prize of the European Association for Structural Dynamics (EASD) 2017, Z.P. Bažant Prize (Czech Society of Mechanics) 2017, Medal of F. Križík (CAS) 2007, State Prize of the Czech Republic (1982).


Institute of Theoretical and Applied Mechanics

Stochastic resonance (SR) is a phenomenon which exists in some nonlinear dynamic systems under combined excitation consisting of a deterministic harmonic force and random noise. This phenomenon was observed for the first in early 1940s when investigating the Brownian motion. Later several disciplines in optics, plasma physics and biomedicine encountered effects of this type. However, the actual discovery and start of intensive period of investigation is dated in early 1980s when the idea of SR initiated remarkable inter disciplinary interest including most areas of physics, chemistry and neuro-physiology with a significant overlap to engineering area.
Promising opportunities to employ SR in mechanics emerged only recently to model certain post-critical effects in non-linear dynamics. It opened a possibility to investigate effectively a number of phenomena occurring in aeroelasticity in civil and aircraft engineering. Simultaneously, the platform of the SR enables to develop new vibration damping devices, energy harvesting facilities, sophisticated measuring technics enhancing sensitivity and resolution and many others.
The phenomenon itself manifests by a stable periodic hopping between two nearly constant limits perturbed by random noises. The occurrence of this phenomenon depends on certain combinations of input parameters, which can be determined theoretically and verified experimentally. The basic version of SR can occur in a bi-stable Duffing type system under suitable combination of the additive Gaussian white noise and harmonic deterministic force. Some non-conventional definitions are also outlined. They concern alternative (non-Duffing) operators and driving processes (non-Gaussian). For completeness also selected extensions beyond classical definition are demonstrated, e.g. systems with continuously distributed parameters, aperiodic SR and quantum SR in nano-mechanical systems.

The aim of the paper is to present information about a new challenging discipline offering a large field of basic research in mechanics and possibilities for practical applications including industrial products of a new generation.



CASE STUDIES IN INDUSTRIAL NOISE CONTROL

A.R. Mohanty
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Dr. A. R. Mohanty is a professor of Mechanical Engineering at the Indian Institute of Technology, Kharagpur, India where he also holds the Shyamal Ghosh and Sunanda Ghosh Chair Professor position. Professor Mohanty obtained his PhD in the areas of Noise Control from the University of Kentucky, USA. He was also a post doctoral fellow at the Ray W. Herrick Labs of Purdue University, USA working in the areas of active control of tire noise. Professor Mohanty has worked in NVH areas at Ford Motor Company in Dearborn and Larsen & Toubro Limited, Mumbai. He has been a consultant to more than a 100 companies in the areas of noise control and machinery condition monitoring. His research interests are in the areas of machinery condition monitoring, industrial noise control and acoustical materials. Dr. Mohanty has more than 200 refereed journal and conference publications; he has one book, five book chapters and one patent to his credit. He has held visiting faculty positions at universities in the USA, France and Singapore. Professor Mohanty is a fellow of the Indian National Academy of Engineering, Acoustical Society of India, Condition Monitoring Society of India, Institution of Engineers India and the International Society of Engineering Asset Management. He has received several national and international awards and scholarships for recognition of his research and teaching.

Mechanical Engineering
Indian Institute of Technology Kharagpur
India

The speaker would present several case studies in industrial noise control from over three decades of research, teaching and consulting experience both in India and abroad. The case studies would be from the sectors of transportation, machineries and environment. In particular, the successful noise reduction in the driver's cabin of a diesel locomotive for the Indian railways would be presented. From the automobile and mining sector, case studies of application of basic vibration reduction techniques to improve the noise vibration and harshness performance of power trains and cabin noise in automobiles and earth moving machinery operator's cabin will be presented. Results from a research study on the active noise control of tire noise in an automobile would be presented too. Some innovative use of engineered natural materials, on-site novel measurement techniques, state-of-the art analysis technique and instrumentation currently used for noise source identification and its control will be discussed. The application of natural materials for noise reduction in refrigerators, vacuum cleaners and clothes dryer would be presented. The significance of few sound quality metrics in designing quieter machinery components, in particular automobile silencers would be demonstrated from results of a jury evaluation. Some case studies on environment noise control for mining and steel plants would also be presented. An example from underwater noise monitoring during piling operations for establishing safe levels for protection of marine animals during expansion of a shipping jetty would be discussed. Recent developments in the areas of sonic crystal and micro-perforates for application in noise control would be presented.



CHALLENGES AND STRATEGIES ON DYNAMICS PROBLEMS IN CHINESE HIGH-SPEED RAILWAYS

Wanming Zhai
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Professor Wanming Zhai is an Academician of Chinese Academy of Sciences (CAS). He graduated from Southwest Jiaotong University (SWJTU) with BS degree in 1985 and received his PhD degree in Railway Vehicle Engineering in 1992. He became a full professor in 1994. In 1999, he was appointed Chang Jiang Chair Professor by the Chinese Ministry of Education. Currently, he is a chair Professor of Railway Engineering at SWJTU, the Chairman of Academic Committee of Southwest Jiaotong University, and the Director of Train and Track Research Institute. Professor Zhai is one of the leading scientists in railway engineering in the world. His research activities are mainly in the field of railway system dynamics, focusing on train-track-bridge interactions. He established a new theoretical framework of vehicle-track coupled dynamics so as to be able to investigate the dynamical problems of overall vehicle and track system. He developed a dynamic model and computational software TTBSIM for solving the large-scale train-track-bridge interaction problems and proposed a method to assess the running safety and ride comfort of high-speed trains passing through different types of bridges at the design stage. His models and methods, well-known as Zhai model and Zhai method, have been successfully applied to more than 20 large-scale field engineering projects for the railway network in China, mostly for high-speed railways. Professor Zhai is the Editor-in-Chief of International Journal of Rail Transportation published by Taylor & Francis Group. He also serves as a trustee of International Association for Vehicle System Dynamics, the President of Chengdu Association for Science and Technology, the vice President of the Chinese Society of Theoretical and Applied Mechanics, and the vice President of the Chinese Society for Vibration Engineering.

Southwest Jiaotong University, China

High-speed railway has achieved rapid development in China during very short period, along with many scientific and technological challenges. In this presentation, an overview is given on the development of high-speed railways in China, including the history of raising train speed and current status of high-speed railways. Key challenges focusing on dynamics problems are discussed at design stage and at operation stage of Chinese high-speed railways, respectively. For example, how to employ the vehicle–track coupled dynamics theory to determine the design parameters of plane curves and vertical profiles for different high speed lines without any design standard at the beginning of development of high-speed railways in China? How to use the train–track–bridge dynamic interaction simulation to evaluate and assess the running safety and ride comfort of high-speed trains passing through various types of bridges at the design stage? How to maintain the high ride comfort of high-speed trains running on various infrastructures at operation stage? Some strategies for coping with the challenges are introduced on the basis of speaker's research work on railway system dynamics, and some application examples are provided to demonstrate their effectiveness in practical high-speed railway engineering.



ACOUSTIC MONITORING AND QUALITY CONTROL BY MEANS OF ARTIFICIAL INTELLIGENCE AND MACHINE LEARNING

Joachim Bös
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Research assistant at the research group System Reliability, Adaptive Structures, and Machine Acoustics SAM, Technische Universität Darmstadt, Darmstadt, Germany

Technische Universität Darmstadt, Darmstadt, Germany

ACOUSTIC MONITORING AND QUALITY CONTROL BY MEANS OF ARTIFICIAL INTELLIGENCE AND MACHINE LEARNING


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