Recent Developments in Nonlinear System Identification and Model Updating

ABSTRACT:

As engineering systems become more complex, reflecting multi-physical effects and possessing responses across different time and frequency scales, the likelihood exists that they will exhibit strongly nonlinear and nonstationary behavior, sensitive to initial and forcing conditions and parameter uncertainties. Examples include structures with loose mechanical joints undergoing vibro-impacts, and ultra-flexible structural components with strong geometric nonlinearities. Our identification approach, still in development, relies solely upon direct time series measurement and post-processing, leading to dual global / local identification of the dynamics and data-driven reduced order models (ROMs). Key to this approach are slow/fast partitions of the measured time series, which when combined with powerful post-processing algorithms leads to identification of the dimensionality of the governing dynamics and determination of accurate reduced-order models.

BIOGRAPHY:

Professor Lawrence A. Bergman received the B.S. in Mechanical Engineering from the Stevens Institute of Technology, and the M.S. in Civil Engineering and Ph.D. in Applied Mechanics from Case Western Reserve University. His research is primarily in the areas of structural dynamics and control, nonlinear dynamics, applied stochastic processes, system identification, and computational methods. He is the author of more than 200 articles in archival journals and books, has co-authored one research monograph, edited or co-edited 6 volumes, and holds 5 United States patents. He was the co-recipient of the 1983 State of the Art in Civil Engineering Award and the 1999 Norman Medal from the American Society of Civil Engineers, and the recipient of the 2001 Senior Research Prize in Computational Stochastic Mechanics from the International Association for Structural Safety and Reliability. He was editor-in-chief of the ASME Journal of Vibration and Acoustics from 2000 through 2004, and served on the editorial boards of the Journal of Vibration and Control, Probabilistic Engineering Mechanics, and Shock and Vibration Digest. He recently completed a one-year term as Chair of the Executive Committee of the Applied Mechanics Division of ASME. Professor Bergman has been a faculty member at the University of Illinois at Urbana-Champaign since 1979, where he is a professor in the Department of Aerospace Engineering with affiliate appointments in the Departments of Civil and Environmental Engineering and of Mechanical Science and Engineering, and where he served as assistant dean of the College of Engineering during the 1996-97 academic year. He is a Fellow of the American Society of Mechanical Engineers and an Associate Fellow of the American Institute of Aeronautics and Astronautics.