IISc Logo    Title

etd AT Indian Institute of Science >
Division of Earth and Environmental Sciences >
Civil Engineering (civil) >

Please use this identifier to cite or link to this item: http://hdl.handle.net/2005/542

Title: Inverse Sensitivity Methods In Linear Structural Damage Detection Using Vibration Data
Authors: Venkatesha, S
Advisors: Manohar, C S
Keywords: Structural Analysis
Vibration Analysis
Inverse Sensitivity
Structural Damage Detection - Algorithms
Structural Dynamics
Vibration Data
Inverse Eigensensitivity
Linear Time Invariant (LTI)
Submitted Date: Mar-2007
Series/Report no.: G21063
Abstract: The thesis addresses the problem of structural damage detection using inverse sensitivity based methods. The focus here is on characterization with regard to identification, location, and, quantification of structural damage in linear time invariant (LTI) systems, using vibration data. The study encompasses both analytical and experimental methods. A suite of five algorithms for damage detection, namely, inverse eigensensitivity method that is refined to account for cross orthogonality between distinct modes, damping dependent eigensolutions, and sensitivity with respect to points of antiresonance and minima, inverse FRF method that includes refinements in terms of inclusion of second order sensitivity, response function method (RFM) based on first order Taylor’s expansion, a newly proposed inverse sensitivity method based on singular values of FRF matrix, and method based on response time histories, are presented. The scope of these methods vis-à-vis the need for model reduction, ability to deal with incomplete data, ill-posedness of governing equations and the need for regularization, sensitivity with respect to measurement noise, ability to identify damping characteristics, the highest and lowest magnitudes of changes in structural properties, and the ability to characterize systems with closely spaced natural frequencies that the methods can detect are discussed. The performance of proposed procedures is illustrated by considering a five degrees-of-freedom (dof) mass-spring-dashpot system and subsequently applied on three archetypal structural systems using analytical and experimental methods. In the examples presented, factors, such as, completeness of measured data in time and frequency, nature (proportional/non-proportional) and magnitude of damping, levels of changes in structural properties, modal truncations, number of governing equations for system parameters, and efficacy of regularization techniques are investigated. The study also highlights the difficulties in implementing the damage detection algorithm based on real life noisy vibration data. A comparative study on the suitability of each of these methods in locating and quantifying of different damage scenarios has been reported. A critical review of performance of the various methods is presented. The thesis concludes with a summary on the contributions made and also deliberates on future avenues for research and development in this area of research.
URI: http://etd.iisc.ernet.in/handle/2005/542
Appears in Collections:Civil Engineering (civil)

Files in This Item:

File Description SizeFormat
G21063.pdf6.02 MBAdobe PDFView/Open

Items in etd@IISc are protected by copyright, with all rights reserved, unless otherwise indicated.


etd@IISc is a joint service of SERC & IISc Library ||
|| Powered by DSpace || Compliant to OAI-PMH V 2.0 and ETD-MS V 1.01