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Proceedings Paper

Dynamic holographic modal analysis for inspecting large civil engineering structures
Author(s): David M. Rosenthal; James D. Trolinger
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Paper Abstract

Cracks and defects in structures can be detected by observing the changes of the vibrational modal patterns and surface responses to stress. Features are made visible with dynamic holographic interferometry combined with parameter estimation. The procedure involves an unconventional, optimized, laser-illumination method. The methods are especially applicable to large structures and could prove pivotal to improved designs, monitoring, and maintenance. Components and structures could be designed to better withstand operating stresses, and existing structures could be analyzed to predict their response to stress. Since the modal characterization of a structure can act as a type of fingerprint, holographic interferometry can also be used to monitor structural degradation due to operating and aging. Modal characterization includes indentification of resonant frequencies and also the corresponding mode shapes. Holographic interferometry provides for direct modal characterization of a structure as well as measuring its small loading dynamic response. This research demonstrated that a wide variety of defects can be located in structural components, vessels, and pipes. An analytical exercise also demonstrates the ability to use global modal characteristics to determine the presence of local corrosion and erosion.

Paper Details

Date Published: 23 June 1995
PDF: 11 pages
Proc. SPIE 2545, Interferometry VII: Applications, (23 June 1995); doi: 10.1117/12.212657
Show Author Affiliations
David M. Rosenthal, MetroLaser (United States)
James D. Trolinger, MetroLaser (United States)

Published in SPIE Proceedings Vol. 2545:
Interferometry VII: Applications
Ryszard J. Pryputniewicz; Gordon M. Brown; Werner P. O. Jueptner, Editor(s)

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