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Accession Number N20120016820
Title Local Guided Wavefield Analysis for Characterization of Delaminations in Composites.
Publication Date Jul 2012
Media Count 8p
Personal Author C. A. Campbell Leckey M. D. Rogge
Abstract Delaminations in composite laminates resulting from impact events may be accompanied by minimal indication of damage at the surface. As such, inspection techniques are required to ensure defects are within allowable limits. Conventional ultrasonic scanning techniques have been shown to effectively characterize the size and depth of delaminations but require physical contact with the structure. Alternatively, a noncontact scanning laser vibrometer may be used to measure guided wave propagation in the laminate structure. A local Fourier domain analysis method is presented for processing guided wavefield data to estimate spatially-dependent wavenumber values, which can be used to determine delamination depth. The technique is applied to simulated wavefields and results are analyzed to determine limitations of the technique with regards to determining defect size and depth. Finally, experimental wavefield data obtained in quasi-isotropic carbon fiber reinforced polymer (CFRP) laminates with impact damage is analyzed and wavenumber is measured to an accuracy of 8.5% in the region of shallow delaminations.
Keywords Carbon fibers
Fiber composites
Imaging techniques
Impact damage
Nondestructive tests
Polymer matrix composites
Ultrasonic tests
Wave propagation

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 71F - Composite Materials
Corporate Author National Aeronautics and Space Administration, Hampton, VA. Langley Research Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1316
Contract Number N/A

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