PLENARY SESSIONS

To download the keynote speakers information, please click (Keynote Speakers).

 

Plenary Speech

Professor Oleg Gendelman
Samuel and Anne Tolkowsky Professor
Faculty of Mechanical Engineering
Technion – Israel Institute of Technology
Haifa, Israel

Photo-Prof. Gendelman
Title:
Strong nonlinearity in vibrations and acoustics: intentional and unintentional
Abstract:
Essentially nonlinear behavior is common in traditional mechanical systems due to clearances, cracks, impacts, friction, material nonlinearities and plasticity. In many of the listed instances, such behavior is unwanted and may be even destructive. In the same time, in in last two decades it was realized that intentional use of strongly nonlinear elements in mechanical systems could bring about significant enhancements and advantages in their performance. In this respect, one can mention targeted energy transfer in essentially nonlinear systems with applications for energy absorption and harvesting, wave propagation in granular crystals, granular media and other systems with acoustic vacuum, acoustic metamaterials with essentially nonlinear elements.All mentioned applications, traditional and modern, involve some form of energy transfers, transient processes and/or wave propagation. Essential nonlinearity poses major challenge for analytic exploration and understanding of these processes. Traditional methods stemming from quasilinear approximation have limited applicability for such problems, and often produce the results with uncontrolled inaccuracy. In certain important cases, for instance, when the impacts are involved, these traditional methods turn irrelevant for exploration of the transient responses.The talk will cover a set of archetypal problems, in which the strong nonlinearity appears as the undesirable complication, or is introduced intentionally to improve the performance. Peculiar features of dynamic responses, and approaches to analytic treatment and qualitative understanding of these phenomena will be discussed.
Biographical Sketch:
Doctor of Sciences (2000), Physics and Mathematics, from the Higher Commission of Attestation, Russian Ministry of Education. PhD (1995), Physics and Mathematics, from N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, RAS.
In 2003 joined Faculty of Mechanical Engineering in Technion, Israel. Now – Shmuel and Ann Tolkowsky Professor of Mechanical Engineering, Technion– Israel Institute of Technology, Haifa, Israel.
Author of about 170 scientific papers and 3 monographs.

Keynote Speech No. 1

Professor Anatoly L. Virovlyansky
Institute of Applied Physics, Russian Academy of Sciences
46 Ul’anov str., 603950, Nizhny Novgorod
Russia

Photo-Dr. Virovlyansky
Title:
Stable components of sound fields in the ocean acoustic waveguide
Abstract:
The main factor reducing the accuracy of field evaluation in the ocean acoustic waveguide is the inevitable inaccuracy of an environmental model used in solving the wave equation. When analyzing this issue, the main attention is usually paid to studying how the uncertainty in the environmental parameters manifests itself in the field predictions and in the solutions of inverse problems. In this presentation another aspect of the problem of inaccurate knowledge of the environmental parameters is considered. Here we propose a method for isolating such components of sound fields, which are weakly sensitive to the sound speed perturbations and can be predicted with a reasonable accuracy even in uncertain environment. Stable component is formed by a narrow beam of rays whose spread in vertical direction,  up to the observation range, remains less than the vertical scale of perturbation. These rays pass through practically the same inhomogeneities and therefore their phases are incremented by the same amount. If the ray amplitudes vary insignificantly, then (i) the stable components of the monochromatic field in the perturbed and unperturbed waveguide differ by only a constant phase factor, and (ii) in the case of transient wave field the perturbation causes only an additional time delay of the stable component as a whole. It is shown how the stable components can be selected from the total wave field using the field expansions in the coherent states and in the normal modes. The existence of stable components is demonstrated by numerical simulation of sound field in a deep water waveguide. The results of observations of stable field components in acoustic measurements made in Lake Ladoga are also presented. The use of stable components in solving inverse problems of underwater acoustics related to the reconstruction of medium parameters and the sound source localization  is discussed.
Biographical Sketch:
D. Sc. (1999) in Acoustics, University of Nizhny Novgorod, Russia.
PhD. (1986) in Waves Theory, Gorky State University, Russia.
Received academic rank of Senior Lecturer from the Ministry of General and Professional Education of Russia, 1998. Received academic rank of Senior Researcher from the State Sertification Committee, 1992, Russia.
In 1989 joined Institute of Applied Physics, Russian Academy of Sciences, now Head of Laboratory and Leading Researcher, Institute of Applied Physics, Russian Academy of Sciences.

Keynote Speech No. 2

Professor Erik A. Johnson
Civil Engineering at the University of Southern California in Los Angeles
Vice Dean for Academic Programs in the USC Viterbi School of Engineering
Associate Chair and Interim Chair of the Sonny Astani Department of Civil and Environmental Engineering
U.S.A.

Photo-Prof Johnson
Title:
Substructure Parameter Identification for Shear Structures and Model Calibration for a Full-Scale Experimental Building Structure
Abstract:
For civil engineering structures, there are extremely important reasons for using data to accurately calibrate models of the structure. For example, predicting the performance of an as-built structure, with or without retrofits, to future natural hazards (possibly hazards that were unknown, or of much greater magnitude than expected, when the structure was originally designed) is essential to evaluating the structure’s safety and serviceability. Further, early detection of damage in a structure is essential to evaluating the effectiveness of repair strategies on structure lifetime.
This seminar will first explore a parameter identification method for certain classes of structural systems — those well modeled by a shear structure or a chain-like structure — that is evaluated substructure-by-substructure. A key feature of this approach is that an appropriately-designed structural control system can enhance the sensitivity of the measurements to each substructure’s parameters, thereby improving the ability to accurately detect changes in those parameters that may indicate damage. Second, time permitting, a case study of updating a high-order finite element model of a full-scale laboratory structure will be discussed; this structure is a 4-story reinforced concrete base-isolated building.
Biographical Sketch:
Dr. Johnson earned B.S., M.S. and Ph.D. degrees in Aeronautical and Astronautical Engineering at the University of Illinois at Urbana-Champaign in 1988, 1993 and 1997, and a Graduate Certificate in Biblical Studies from Trinity Evangelical Divinity School. Dr. Johnson was the recipient of a 2001 Early Faculty Career Development (CAREER) Award from the U.S. National Science Foundation, a 2005 Junior Research Prize and Medal from the International Association for Structural Safety and Reliability (IASSAR), and a 2016 Distinguished AE Alumnus Award from the University of Illinois. He is a senior member of the American Institute of Aeronautics and Astronautics (AIAA), and a member of both the American Society of Civil Engineers (ASCE) and the American Society of Mechanical Engineers (ASME). Dr. Johnson served as Chair of the ASCE EMI Technical Committee on Structural Health Monitoring and Control, is the current Chair of the ASCE EMI Probabilistic Methods Committee, and serves on the Board of Directors of the American Automatic Control Council.
Dr. Johnson’s research interests include “smart” structures, control and monitoring of structural vibration, controllable damping devices, random vibration, and computationally-efficient simulation algorithms for dynamical systems..

 

Workshop No. 1

Professor Anatoly L. Virovlyansky
Institute of Applied Physics, Russian Academy of Sciences
46 Ul’anov str., 603950, Nizhny Novgorod
Russia

 Photo-Dr. Virovlyansky
Title:
Relationship between the ray and mode representations of the wave field in an underwater acoustic waveguide
Abstract:
The method of geometrical optics and the method of normal modes give two alternative expressions for the complex amplitude of the sound field in a range-independent waveguide in the form of sums over the rays and normal modes. Both sums represent the same field and can be transformed into each other using the Poisson summation formula. However, there is a much more subtle and detailed relationship between these field representations, which is discussed in the presentation. It consists in the fact that groups of constructively interfering (adding in phase) modes can form contributions of individual rays and, conversely, groups of constructively interfering rays can form contributions of individual modes. This relationship takes place for both monochromatic  and transient sound fields. It is observed not only in range-independent waveguides, but also in range-dependent ones. The use of ray-mode relations provides an unexpectedly simple ray based description of normal mode amplitudes. This approach makes it possible to derive an analytical description of the statistics of the mode amplitudes in a waveguide with large-scale sound speed fluctuations. It is shown that for description of the diffraction effects in the waveguide, it is possible to introduce the Fresnel zones of modes representing modal analogues of the classical Fresnel zones of rays. General statements are illustrated by numerical examples for a deep-ocean waveguide with a Munk sound speed profile and sound speed fluctuations induced by random internal waves.
Biographical Sketch:
D. Sc. (1999) in Acoustics, University of Nizhny Novgorod, Russia.
PhD. (1986) in Waves Theory, Gorky State University, Russia.
Received academic rank of Senior Lecturer from the Ministry of General and Professional Education of Russia, 1998. Received academic rank of Senior Researcher from the State Sertification Committee, 1992, Russia.
In 1989 joined Institute of Applied Physics, Russian Academy of Sciences, now Head of Laboratory and Leading Researcher, Institute of Applied Physics, Russian Academy of Sciences.

Workshop No. 2

Professor Erik A. Johnson
Civil Engineering at the University of Southern California in Los Angeles
Vice Dean for Academic Programs in the USC Viterbi School of Engineering
Associate Chair and Interim Chair of the Sonny Astani Department of Civil and Environmental Engineering
U.S.A.

Photo-Prof Johnson
Title:
Controllable Damping Strategies for Large-Scale Civil Structures
Abstract:
This tutorial session will introduce the concept of controllable damping devices, explaining why such devices are needed, some examples of how they function, and some applications where they have been studied and implemented, particularly for large-scale civil structures such as buildings and bridges.  Some case studies will be discussed for controllable damping in base isolated buildings, to help dissipate energy while minimizing the coupling of the superstructure response to the ground motion, and in dissipating the vibratory energy of cables in a cable-stayed bridge.
Biographical Sketch:
Dr. Johnson earned B.S., M.S. and Ph.D. degrees in Aeronautical and Astronautical Engineering at the University of Illinois at Urbana-Champaign in 1988, 1993 and 1997, and a Graduate Certificate in Biblical Studies from Trinity Evangelical Divinity School. Dr. Johnson was the recipient of a 2001 Early Faculty Career Development (CAREER) Award from the U.S. National Science Foundation, a 2005 Junior Research Prize and Medal from the International Association for Structural Safety and Reliability (IASSAR), and a 2016 Distinguished AE Alumnus Award from the University of Illinois. He is a senior member of the American Institute of Aeronautics and Astronautics (AIAA), and a member of both the American Society of Civil Engineers (ASCE) and the American Society of Mechanical Engineers (ASME). Dr. Johnson served as Chair of the ASCE EMI Technical Committee on Structural Health Monitoring and Control, is the current Chair of the ASCE EMI Probabilistic Methods Committee, and serves on the Board of Directors of the American Automatic Control Council.
Dr. Johnson’s research interests include “smart” structures, control and monitoring of structural vibration, controllable damping devices, random vibration, and computationally-efficient simulation algorithms for dynamical systems.

Workshop No. 3

Professor Oleg Gendelman
Samuel and Anne Tolkowsky Professor
Faculty of Mechanical Engineering
Technion – Israel Institute of Technology
Haifa, Israel

Photo-Prof. Gendelman
Title:
Regular and singular perturbation in nonlinear dynamics