title: An Improved Method of Parameter Identification and Damage Detection in Beam Structures under Flexural Vibration Using Wavelet Multi-Resolution Analysis.
abstract: This paper reports on a two-step approach for optimally determining the location and severity of damage in beam structures under flexural vibration. The first step focuses on damage location detection. This is done by defining the damage index called relative wavelet packet entropy (RWPE). The damage severities of the model in terms of loss of stiffness are assessed in the second step using the inverse solution of equations of motion of a structural system in the wavelet domain. For this purpose, the connection coefficient of the scaling function to convert the equations of motion in the time domain into the wavelet domain is applied. Subsequently, the dominant components based on the relative energies of the wavelet packet transform (WPT) components of the acceleration responses are defined. To obtain the best estimation of the stiffness parameters of the model, the least squares error minimization is used iteratively over the dominant components. Then, the severity of the damage is evaluated by comparing the stiffness parameters of the identified model before and after the occurrence of damage. The numerical and experimental results demonstrate that the proposed method is robust and effective for the determination of damage location and accurate estimation of the loss in stiffness due to damage.
authors.affiliation: StrucHMRS Group, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. r.ravanfar@gmail.com.
authors.forename: Seyed Alireza
authors.initials: SA
authors.lastname: Ravanfar
authors.affiliation: StrucHMRS Group, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. hashim@um.edu.my.
authors.forename: Hashim Abdul
authors.initials: HA
authors.lastname: Razak
authors.affiliation: Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. zu_ismail@um.edu.my.
authors.forename: Zubaidah
authors.initials: Z
authors.lastname: Ismail
authors.affiliation: StrucHMRS Group, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. hooman_monajemi@yahoo.com.
authors.forename: Hooman
authors.initials: H
authors.lastname: Monajemi
keywords: beam structure under flexural vibration; damage detection; relative wavelet packet entropy; time-varying system identification; wavelet transform