Investigation on vibration excitation of debonded sandwich structures using time-average digital holography
Authors:
- 6 February 2017
- journal article
- Published by Optica Publishing Group in Applied Optics
- Vol. 56 (13) , F7-F13
Abstract
Sandwich structures, in the modern aerospace industry, are more sought after due to their high strength to stiffness ratio resulting in significant weight gains. Optical techniques like time-average holography and shearography are preferred in industries for inspection of huge sandwich and composite panels because of whole-field (full coverage) inspection in a lesser time leading to large savings in cost. These techniques conventionally use sinusoidal frequency sweep to capture the local resonance of defective regions. This paper highlights the difficulties with the conventional approach of time-average digital holography (TADH) and proposes a novel defect identification strategy through square wave excitation. The proposed method enhances the speed and accuracy of inspection; thereby it saves cost and increases confidence level. Extensive experiments have been carried out using honeycomb sandwich panels to demonstrate the methodology.Keywords
This publication has 11 references indexed in Scilit:
- Digital Shearography and vibration excitation for NDT of aircraft componentsAIP Conference Proceedings, 2014
- Vibration-Based Structural Health Monitoring – Concepts and ApplicationsKey Engineering Materials, 2005
- Time-averaged digital holographyOptics Letters, 2003
- Evaluating the soundness of bonding using shearographyComposite Structures, 2000
- Digital recording and numerical reconstruction of holograms: reduction of the spatial frequency spectrumOptical Engineering, 1996
- Flaw detection in composites using time-average shearographyOptics & Laser Technology, 1991
- Characteristic Functions for Time-Average HolographyJournal of the Optical Society of America, 1970
- Vibration analysis by holographyReports on Progress in Physics, 1970
- Hologram Interferometry*†Journal of the Optical Society of America, 1966
- Interferometric Vibration Analysis by Wavefront ReconstructionJournal of the Optical Society of America, 1965