Damage Identification in Beam-like Structures by Vibration-based Analysis and Artificial Neural Networks

Tez Türü: Doktora

Tezin Yürütüldüğü Kurum: University of Southampton, Birleşik Krallık

Tez Danışmanı: Professor R. A. Shenoi

Tezin Onay Tarihi: 2004

Tezin Dili: İngilizce

Desteklendiği Program: Diğer

Özet:

Laminated composites and sandwich structures are increasingly being used in different

engineering applications such as in aeronautical, marine and offshore structures where high

stiffness, light weight, good corrosion resistance and temperature stability are the primary

issues. During their service life, these structures experience extreme loadings and harsh

environmental conditions potentially leading to structural damage. This could significantly

reduce mechanical strength and result in performance degradation of the structure.

Therefore, in order to maintain the performance of the structure, localisation and quantification

of the damage is a promising research area. Since the determination of the severity and the

location of the damage is an inverse and non-unique problem, an intelligent algorithm is needed

to perform the damage detection analysis.

This study presents a damage detection algorithm, which uses vibration-based analysis data

obtained from beam-like structures to locate and quantify the damage by using artificial neural

networks. The inputs and the corresponding outputs required to train the neural networks are

obtained from the finite element analyses for different vibration modes of the beams. Multilayer

feedforward backpropogation neural networks have been designed and trained by using

different damage scenarios. After validation of the neural networks, new damage cases obtained

from finite element and experimental analyses have been introduced and neural networks have

been tested for location and severity predictions.

The results from the neural networks depict that severity and location of the damage can be

predicted by using as input the global (natural frequencies) and the local (strain or curvature

mode shapes) dynamic behaviour of the beam-like structures.