DAMAGE ASSESSMENT POTENTIAL OF A NOVEL SYSTEM IDENTIFICATION TECHNIQUE - EXPERIMENTAL VERIFICATION

Persistent Link:
http://hdl.handle.net/10150/193974
Title:
DAMAGE ASSESSMENT POTENTIAL OF A NOVEL SYSTEM IDENTIFICATION TECHNIQUE - EXPERIMENTAL VERIFICATION
Author:
Martinez-Flores, Rene
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Experimental verification of a novel system identification technique that can detect defects at the element level is successfully accomplished. The method can be used for in-service health assessment of real structures without disrupting normal operations. This study conclusively verifies the method.Analytical verification of the proposed algorithm has been successfully completed by the research team at the University of Arizona. Vo and Haldar (2004) experimentally verified the method by conducting tests on fixed-ended and simply supported defect-free and defective beams. The purpose of this research was to validate the method by conducting experiments with more realistic structures. A three-story one-bay steel frame, built to 1/3 scale to fit the experimental facility, was considered. The frame was excited by harmonic or impulsive excitation forces. The transverse acceleration responses were collected using capacitive accelerometers. The angular displacement responses were measured using an autocollimator. The dynamic responses of the frames were collected by a data acquisition system with simultaneous sampling capability. Using only experimentally collected response information and completely ignoring the excitation information, the stiffness of all the structural elements were identified. The method identified the defect-free frame very accurately. Defects, in terms of removing a beam, reducing cross sectional area over a small segment of a beam, and cutting notches in a beam, were introduced. The method correctly identified the defect location in all cases. Additional sensors were placed around the location of the defect in an effort to identify the defect spot more accurately. The proposed method also successfully identified defect with improved accuracy. To increase the implementation potential of the proposed method, the defect-free and defective frames are then identified using limited response information. A two-stage Kalman filter-based approach is used. It is denoted as Generalized Iterative Least Square Extended Kalman Filter with Unknown Input (GILS-EKF-UI) method. A sub-structure approach is used for this purpose. The GILS-EKF-UI method also identified the state of the structure using only limited response information. As expected, in this case the error in the identification goes up as less information is used. However, the error is much smaller than other methods currently available in the literature, even when input excitation was used for the identification purpose. The method is very robust and can identify defects caused by different types of loadings. The method can be used as a nondestructive defect assessment technique for structures.
Type:
text; Electronic Dissertation
Keywords:
Structural; Health Assessment; Dynamic
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Civil Engineering; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Haldar, Achintya

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleDAMAGE ASSESSMENT POTENTIAL OF A NOVEL SYSTEM IDENTIFICATION TECHNIQUE - EXPERIMENTAL VERIFICATIONen_US
dc.creatorMartinez-Flores, Reneen_US
dc.contributor.authorMartinez-Flores, Reneen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractExperimental verification of a novel system identification technique that can detect defects at the element level is successfully accomplished. The method can be used for in-service health assessment of real structures without disrupting normal operations. This study conclusively verifies the method.Analytical verification of the proposed algorithm has been successfully completed by the research team at the University of Arizona. Vo and Haldar (2004) experimentally verified the method by conducting tests on fixed-ended and simply supported defect-free and defective beams. The purpose of this research was to validate the method by conducting experiments with more realistic structures. A three-story one-bay steel frame, built to 1/3 scale to fit the experimental facility, was considered. The frame was excited by harmonic or impulsive excitation forces. The transverse acceleration responses were collected using capacitive accelerometers. The angular displacement responses were measured using an autocollimator. The dynamic responses of the frames were collected by a data acquisition system with simultaneous sampling capability. Using only experimentally collected response information and completely ignoring the excitation information, the stiffness of all the structural elements were identified. The method identified the defect-free frame very accurately. Defects, in terms of removing a beam, reducing cross sectional area over a small segment of a beam, and cutting notches in a beam, were introduced. The method correctly identified the defect location in all cases. Additional sensors were placed around the location of the defect in an effort to identify the defect spot more accurately. The proposed method also successfully identified defect with improved accuracy. To increase the implementation potential of the proposed method, the defect-free and defective frames are then identified using limited response information. A two-stage Kalman filter-based approach is used. It is denoted as Generalized Iterative Least Square Extended Kalman Filter with Unknown Input (GILS-EKF-UI) method. A sub-structure approach is used for this purpose. The GILS-EKF-UI method also identified the state of the structure using only limited response information. As expected, in this case the error in the identification goes up as less information is used. However, the error is much smaller than other methods currently available in the literature, even when input excitation was used for the identification purpose. The method is very robust and can identify defects caused by different types of loadings. The method can be used as a nondestructive defect assessment technique for structures.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectStructuralen_US
dc.subjectHealth Assessmenten_US
dc.subjectDynamicen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineCivil Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairHaldar, Achintyaen_US
dc.contributor.committeememberHaldar, Achintyaen_US
dc.contributor.committeememberRichard, Ralphen_US
dc.contributor.committeememberFleischman, Roberten_US
dc.contributor.committeememberContractor, Dunshaw N.en_US
dc.identifier.proquest1028en_US
dc.identifier.oclc137353581en_US
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