Sensitivity analysis of a transmission line model for damage characterization in complex structures

Dany Francoeur; Patrice Masson; Philippe Micheau

doi:10.1117/12.811935

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26 March 2009 Sensitivity analysis of a transmission line model for damage characterization in complex structures

Dany Francoeur, Patrice Masson, Philippe Micheau

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Proceedings Volume 7295, Health Monitoring of Structural and Biological Systems 2009; 729504 (2009) https://doi.org/10.1117/12.811935
Event: SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, 2009, San Diego, California, United States

Abstract

With the goal to detect relatively small damage while minimizing signal processing burden, an approach in the medium frequency range (10 kHz - 50 kHz) is proposed for the characterization of a damage in a complex assembly structure and more specifically, a lap joint. The approach is based on the identification of the parameters of a reference transmission line model of a damaged lap joint structure through the experimental measurement of a reflection coefficient. The transmission line model of the lap joint is first presented, where symmetrical thickness variations on a beam are used to represent the lap joint region and a notch within this region. The cost function used in the model identification approach is then defined as the squared difference between simulated and measured reflection coefficients in a given frequency range. A sensitivity analysis is conducted using the Hessian of the cost function and simulation results are presented to demonstrate the sensitivity of the cost function to variations in the sought parameters, i.e. location and depth of the notch, in the frequency domain. Experimental results are then presented to assess the sensitivity of the cost function to the variation of the depth of the notch. These experimental results confirm the simulation results which indicate that the sensitivity of the cost function to the depth of the notch increases as this depth increases. Moreover, cross-sensitivity results indicate that the sensitivity of the cost function to the location of the notch also increases as the depth of the notch increases.

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Dany Francoeur, Patrice Masson, and Philippe Micheau "Sensitivity analysis of a transmission line model for damage characterization in complex structures", Proc. SPIE 7295, Health Monitoring of Structural and Biological Systems 2009, 729504 (26 March 2009); https://doi.org/10.1117/12.811935

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