暨南大学理工学院科技沙龙系列-90

 
 
题  目：Bridge Structural Health Monitoring Based on Vibration and Traffic Monitoring
主讲人：Professor Chin-An Tan, Fellow ASME / Wayne State University, USA
主持人：马宏伟 教授 / 余岭 教授
时  间：2009年10月26日（星期一）上午10：30-12：00
地  点：蒙民伟理工楼学术报告厅(103#)
 
ABSTRACT
 
Structural condition assessment of highway bridges has traditionally been performed by visual inspections or nondestructive evaluation techniques, which are either slow, unreliable or detects only local flaws.  Instrumentation of bridges with accelerometers and other sensors, however, can provide real-time data useful for monitoring the global structural conditions of the bridges due to ambient and forced excitations.  However, the problem of interpreting these data can be challenging since the input (e.g., traffic excitation) is difficult to measure/quantify and that the structural parameters, for which we are interested in monitoring, may not be completely known.  In this presentation, we report a video-assisted approach for structural health monitoring of highway bridges, with results from field tests and subsequent offline parameter identification.  The field tests were performed on a short-span instrumented bridge whose vibration is predominantly due to traffic excitation.  Videos of vehicles passing by were captured, synchronized with data recordings from the accelerometers.  A probabilistic model of traffic excitation on bridges is first developed assuming that vehicles traversing a bridge (modeled as an elastic beam) form a sequence of Poisson process moving loads and that the contact force of a vehicle on the bridge deck can be converted to equivalent dynamic loads at the nodes of the beam elements.  Basic information of vehicle types, arrival times and speeds are extracted from video images to develop a physics-based simulation model of the traffic excitation.  This modeling approach aims at circumventing a difficulty in the output-only system identification of bridge structural parameters, in which the parameter identification is often based on the measured response (or system output) only, and knowledge of the input (traffic excitation) is either unknown or assumed, making it difficult to obtain an accurate assessment of the state of the bridge structure.  Our model reveals that traffic excitation on bridges is spatially correlated, an important feature that is usually incorrectly ignored in most output-only methods.  The partial traffic information is incorporated in a Bayesian framework to assess the structural condition of the bridge super-structure.  The effectiveness and viability of this video-assisted approach are demonstrated by the field results.
 
Short Biography of Prof. C. A. Tan:
 
Dr. Chin-An Tan was born and raised in Hong Kong.  He graduated from the University of California at Berkeley with B.S. and Ph.D. degrees in Mechanical Engineering, and from the California Institute of Technology with a M.S. degree in Aeronautics.  Upon completing graduate studies, he joined the Mechanical Engineering Department of Wayne State University in 1989, and is currently a Professor.  His research and technical interests lie in the fields of structural dynamics and vibration, energy recovery, mechatronics, system identification, and NVH applications.  Current research interests focus on: (1) dynamics and controls problems related to energy recovery and power harvesting; (2) moving loads problems; and (3) signal analysis and applications to SHM and controls.
 
Dr. Tan is a Fellow of the American Society of Mechanical Engineers (ASME).  He currently serves on the Editorial Boards of the ASME Applied Mechanics Review.  He also served as an Associate Editor of the ASME Journal of Vibration and Acoustics from 2002-2007, an Associate Dean of Engineering at Wayne State from 2002 to 2003, and on the Editorial Board of the Communications in Nonlinear Science and Numerical Simulations.
 
Dr. Tan has been rated as one of the most outstanding professors at Wayne State University and has won numerous teaching awards including the University President’s Award for Excellence in Teaching — the highest level of recognition for excellence in teaching.  He is currently authoring an undergraduate textbook titled Numerical Methods Using MATLAB: Principles and Practice, and is planning to author a series of textbooks focusing on understanding the fundamental principles and practicing these principles to solve real-world engineering problems.
 
欢迎教师和同学踊跃参与！
 
作者：吉念宁