Huynh, Dung (2003) Damage detection in structures using frequency response function (FRF) data and finite element modelling. Research Master thesis, Victoria University of Technology.

Abstract

This thesis presents a method to detect structural damage using frequency response function (FRF) data obtained from non-destructive vibration tests. The method is used to study cases of early structural damage in which there is no appreciable change in mass and damping. The resulting change in structural stiffness matrix is reflected in changes of FRF which can be exemplified by the evaluation of the damage location vector. This requires the dynamic stiffness matrix of the original undamaged structure and the frequency response curve of the currently damaged structure. In this thesis, the former is obtained from a finite element model of the virgin structure and the latter are obtained from an impact hammer test. The Damage Detection Algorithm will be used to detect simulated damage FRF data applied to a simple mass spring system, space truss structure and a plate structure and effects of noise. Both numerically simulated and experimentally measured noises are investigated. Experimental FRF data were obtained for a plate structure and used for detection of physical damage and comparisons made with the simulated data. Results show that the Damage Detection Algorithm can be used to successfully detect structure damage in situations where coordinate incompatibility and noise exists.

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