Modeling and Simulation of Structures with Frequency-dependent Stiffness and Damping

  Speaker:
  Billie F. Spencer, Jr.
  Nathan M. and Anne M. Newmark Endowed Chair
  of Civil Engineering
  Director, Newmark Structural Engineering Laboratory
  University of Illinois at Urbana-Champaign

  Time: Jun. 6, 2014, 15:30-16:30
                                 Venue: Civil Engineering B504, Chair: Prof. Huanjun Jiang

Outline :

This presentation discusses a new approach for modeling the response of structures that contain discrete elements with linear frequency-dependent stiffness and damping characteristics. While many structures exhibit such frequency-dependent phenomena analyzing such structures can be challenging. This research proposes a rational polynomial approximation (RPA) method which consists of two steps: First, system identification is performed to obtain a rational polynomial approximation for the system’s transfer functions. Then, a time-domain model for the system is realized. The main advantage of the RPA method is that the resulting model is a system of ordinary differential equations, facilitating time history analysis of both linear and nonlinear structures using standard time-step integration algorithms and procedures. The efficacy of the RPA method is verified through several numerical examples employing structures with viscoelastic (VE) dampers, which has both frequency-dependent stiffness and damping. When using VE dampers in analysis, effective modeling of the frequency-dependent characteristics of the VE damper plays a key role in accurate simulation of structural responses. The results demonstrate that the RPA method is effective and efficient for modeling structures with frequency-dependent stiffness and damping elements.
 

About the Speaker:
B.F. Spencer, Jr. received his Ph.D. in theoretical and applied mechanics from the University of Illinois at Urbana-Champaign in 1985. He worked on the faculty at the University of Notre Dame for 17 years before returning to the University of Illinois at Urbana-Champaign, where he currently holds the Nathan M. and Anne M. Newmark Endowed Chair in Civil Engineering and is the Director of the Newmark Structural Engineering Laboratory. His research has been primarily in the areas of smart structures, stochastic fatigue, stochastic computational mechanics, and natural hazard mitigation. He is a Fellow of ASCE, a Foreign Member of the Polish Academy of Sciences, the North American Editor in Chief of Smart Structures and Systems, and the past president of the Asia-Pacific Network of Centers for Research in Smart Structures Technology.

All interested are welcome!