Abstract/Details

Symbolic and numeric solutions of modified bang -bang control strategies for performance-based assessment of base -isolated structures


2005 2005

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Abstract (summary)

This work explores symbolic and numeric solutions to the Lyapunov matrix equation as it applies to performance-based assessment of base-isolated structures supplemented by modified bang-bang control. Traditional studies of this type rely on numeric simulations alone. This study is the first to use symbolic analysis as a means of identifying key “cause and effect” relationships existing between parameters of the active control problem and the underlying differential equations of motion. We show that symbolic representations are very lengthy, even for structures having a small number of degrees of freedom. However, under certain simplifying assumptions, symbolic solutions to the Lyapunov matrix equation assume a greatly simplified form (thereby avoiding the need for computational solutions).

Regarding the behavior of the bang-bang control strategy, further analysis shows: (1) for a 1-DOF system, the actuator force acts very nearly in phase, but in opposite direction to the velocity (90° out of phase and in opposite direction to the displacement), and (2) for a wide range of 2-DOF nonlinear base-isolated models, bang-bang control is insensitive to nonlinear deformations in the isolator devices. Through nonlinear time-history analysis, we see that one- and two-DOF models are good indicators of behavior in higher DOF models.

An analytical framework for system assessment through energy- and power-balance analysis is formulated. Computational experiments on base-isolated systems are conducted to identify and quantitatively evaluate situations when constant stiffness bang-bang control can significantly enhance overall performance, compared to base isolation alone, and assess the ability of present-day actuator technologies to deliver actuator power requirements estimated through simulation.

Indexing (details)


Subject
Civil engineering
Classification
0543: Civil engineering
Identifier / keyword
Applied sciences; Bang-bang control; Base-isolated; Lyapunov matrix equation
Title
Symbolic and numeric solutions of modified bang -bang control strategies for performance-based assessment of base -isolated structures
Author
Sebastianelli, Robert R., Jr.
Number of pages
213
Publication year
2005
Degree date
2005
School code
0117
Source
DAI-B 66/06, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
0542183307, 9780542183300
Advisor
Austin, Mark A.
University/institution
University of Maryland, College Park
University location
United States -- Maryland
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3178589
ProQuest document ID
304992335
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304992335
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