Title: A Bayesian methodology for crack identification in structures using strain measurements

Authors: S. Gaitanaros, G. Karaiskos, C. Papadimitriou, N. Aravas

Addresses: Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334, Greece. ' Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334, Greece. ' Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334, Greece. ' Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334, Greece

Abstract: A Bayesian system identification methodology is presented for estimating the crack location, size and orientation in a structure using strain measurements. The Bayesian statistical approach combines information from measured data and analytical or computational models of structural behaviour to predict estimates of the crack characteristics along with the associated uncertainties, taking into account modelling and measurement errors. An optimal sensor location methodology is also proposed to maximise the information that is contained in the measured data for crack identification problems. For this, the most informative, about the condition of the structure, data are obtained by minimising the information entropy measure of the uncertainty in the crack parameter estimates. Both crack identification and optimal sensor location formulations lead to highly non-convex optimisation problems in which multiple local and global optima may exist. A hybrid optimisation method, based on evolutionary strategies and gradient-based techniques, is used to determine the global minima. The effectiveness of the proposed methodologies is illustrated using simulated data from a single crack in a thin plate subjected to static loading.

Keywords: crack identification; Bayesian analysis; information entropy; sensor placement; structures; strain measurements; structural behaviour; sensor location; optimisation; thin plates; static loading.

DOI: 10.1504/IJRS.2010.032446

International Journal of Reliability and Safety, 2010 Vol.4 No.2/3, pp.206 - 237

Published online: 02 Apr 2010 *

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