With Prof. Hui Li’s gracious invitation, Prof. B.F. Spencer, from University of Illinois at Urbana-Champaign (UIUC) will visit Center of Structural Monitoring and Control (SMC), School of Civil Engineering at HIT and make a presentation on July 30. We sincerely welcome the interested faculties and students to join in the seminar.
Topic: The Role of Complex Mode Shapes and Frequencies in Structural Dynamics
July 30, 3:00pm-5:00pm
Room 402, School of Civil Engineering
When discrete dampers are placed in a structure, the damping matrix does not generally diagonalize using classical modal analysis methods. To analyze such problems, a state space approach must be considered. The associated eigenvalue problem results in complex frequencies and mode shapes. This lecture will briefly review classical modal analysis and then provide some examples where this approach is not applicable. The state space formulation will be introduced subsequently to demonstrate how to solve such problems. The interpretation and use of these complex mode shapes and frequencies will then be presented, and of the errors resulting from the Rayleigh damping approximation will be explored. By the conclusion of the lecture, students/researchers should be comfortable in using these important analysis tools.
Biography of Prof. B.F. Spencer
Professor B.F. Spencer Jr. is the Nathan M. and Anne M. Newmark Endowed Chair in Civil Engineering at the University of Illinois. He holds a B.S. in Mechanical Engineering (University of Missouri – Rolla 1981), and M.S. and Ph.D. in Theoretical and Applied Mechanics (University of Illinois at Urbana-Champaign 1983, 1985). He joined the faculty of the department of Civil and Environmental Engineering at the University of Illinois in 2002. Dr. Spencer served as a professor at the University of Notre Dame from 1985-2002, where he held the Leo E. and Patti Ruth Linbeck Professor of Engineering.
Dr. Spencer has taught graduate and undergraduate courses in structural mechanics, structural dynamics, and structural reliability. He is the author of two books. The first is a monograph entitled, On the Reliability of Nonlinear Hysteretic Structures Subjected to Broadband Random Excitation (Springer-Verlag 1986). The second book, coauthored with Prof. K. Sobczyk, is entitled, Random Fatigue: From Data to Theory (Academic Press 1992).
Dr. Spencer is a Fellow of the American Society of Civil Engineers (ASCE), was the founding chair of the Committee on Structural Control and is the past chair of the Committee on Fatigue and Fracture Reliability, both in the ASCE Structures Division. He serves on the editorial board of the Journal of Structural Control and has served as associate editor for the ASCE Journal of Structural Engineering. He is also a Foreign Member of the Polish Academy of Sciences, the North American Editor in Chief of Smart Structures and Systems, and the president of the Asia-Pacific Network of Centers for Research in Smart Structures Technology.
Dr. Spencer has research interests primarily in the areas of smart wireless sensor technology, damage detection and health monitoring, structural control, stochastic fatigue, stochastic computational mechanics, earthquake engineering, and civil engineering applications of information technology.