Author

Bassam Elsaid

Abstract

This thesis covers the development of a model updating technique which relies on the introduction of correction factors to the elemental stiffness matrix of a beam Finite Element Model (FEM). A Genetic Algorithm selects the values of correction factors by minimizing the difference between an experimentally measured Frequency Response Function (FRF) and the FRF calculated from the FEM being updated. The model updating technique was employed as a damage detection algorithm. The first phase of damage detection is to use model updating to eliminate experimental and modeling errors between the FRF of a beam measured experimentally and the FRF of the same beam calculated by FEM. The second step of damage detection is to employ the model updating process to match the FRF of a damaged beam measured experimentally to the response of the updated FEM. A damage index based on the change in FEM correction factors during the second phase is applied to locate damage. Three different cost functions were evaluated and tuned against two different damage cases measured experimentally. Later the best cost function was tested against two damage cases with smaller damage magnitude. The damage detection algorithm showed reasonable accuracy in determining the damage location in all cases. Additionally, this thesis covers the adaptation of strain gauges for dynamic measurement and the associated signal processing and filtering.

Department

Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Date of Award

6-1-2010

Online Submission Date

March 2013

First Advisor

Arafa, Mustafa

Committee Member 1

El Haggar, Salah

Committee Member 2

Nassef, Ashraf

Document Type

Thesis

Extent

86 p.

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy. The author has granted the American University in Cairo or its agents a non-exclusive license to archive this thesis, dissertation, paper, or record of study, and to make it accessible, in whole or in part, in all forms of media, now or hereafter known.

IRB

Not necessary for this item

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