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Defect Localization Capabilities of a Global Detection Scheme: Spatial Pattern Recognition Using Full-field Vibration Test Data in PlatesRecently, a conceptually simple approach, based on the notion of defect energy in material space has been developed and extensively studied (from the theoretical and computational standpoints). The present study focuses on its evaluation from the viewpoint of damage localization capabilities in case of two-dimensional plates; i.e., spatial pattern recognition on surfaces. To this end, two different experimental modal test results are utilized; i.e., (1) conventional modal testing using (white noise) excitation and accelerometer-type sensors and (2) pattern recognition using Electronic speckle pattern interferometry (ESPI), a full field method capable of analyzing the mechanical vibration of complex structures. Unlike the conventional modal testing technique (using contacting accelerometers), these emerging ESPI technologies operate in a non-contacting mode, can be used even under hazardous conditions with minimal or no presence of noise and can simultaneously provide measurements for both translations and rotations. Results obtained have clearly demonstrated the robustness and versatility of the global NDE scheme developed. The vectorial character of the indices used, which enabled the extraction of distinct patterns for localizing damages proved very useful. In the context of the targeted pattern recognition paradigm, two algorithms were developed for the interrogation of test measurements; i.e., intensity contour maps for the damaged index, and the associated defect energy vector field plots.
Document ID
20020082888
Acquisition Source
Glenn Research Center
Document Type
Contractor Report (CR)
Authors
Saleeb, A. F. (Akron Univ. Akron, OH United States)
Prabhu, M. (Akron Univ. Akron, OH United States)
Arnold, S. M.
Date Acquired
September 7, 2013
Publication Date
August 1, 2002
Subject Category
Structural Mechanics
Report/Patent Number
NAS 1.26:211685
E-13414
NASA/CR-2002-211685
Funding Number(s)
PROJECT: RTOP 708-87-13
CONTRACT_GRANT: NCC3-808
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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