NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Lamb wave characterization of the effects of long-term thermal-mechanical aging on composite stiffnessLamb waves offer a promising method of evaluating damage in composite materials. The Lamb wave velocity is directly related to the material parameters, so an effective tool exists to monitor damage in composites by measuring the velocity of these waves. The Lamb Wave Imager (LWI) uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide frequency range. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the dispersion curve. In this study, the time-of-flight as well as the elastic stiffnesses D11, D22, A44, and A55 for composite samples which have undergone combined thermal and mechanical aging are obtained. The samples examined include a baseline specimen with 0 cycles, specimens which have been aged 2350 and 3530 cycles at high strain levels, and one specimen aged 3530 cycles at low strain levels.
Document ID
20040141825
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Seale, M. D. (NASA Langley Research Center Hampton VA United States)
Madaras, E. I.
Date Acquired
August 22, 2013
Publication Date
September 1, 1999
Publication Information
Publication: The Journal of the Acoustical Society of America
Volume: 106
Issue: 3 Pt 1
ISSN: 0001-4966
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other