Thermal and ultrasonic evaluation of porosity in composite laminatesThe effects of porosity on damage incurred by low-velocity impact are investigated. Specimens of graphite/epoxy composite were fabricated with various volume fractions of voids. The void fraction was independently determined using optical examination and acid resin digestion methods. Thermal diffusivity and ultrasonic attenuation were measured, and these results were related to the void volume fraction. The relationship between diffusivity and fiber volume fraction was also considered. The slope of the ultrasonic attenuation coefficient was found to increase linearly with void content, and the diffusivity decreased linearly with void volume fraction, after compensation for an approximately linear dependence on the fiber volume fraction.
Document ID
19930035628
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Johnston, Patrick H. (NASA Langley Research Center Hampton, VA, United States)
Winfree, William P. (NASA Langley Research Center Hampton, VA, United States)
Long, Edward R., Jr. (NASA Langley Research Center Hampton, VA, United States)
Kullerd, Susan M. (Lockheed Engineering & Sciences Co. Hampton, VA, United States)
Nathan, N. (NASA Langley Research Center Hampton, VA, United States)
Partos, Richard D. (Analytical Services and Materials, Inc. Hampton, VA, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: Review of progress in quantitative nondestructive evaluation. Vol. 11B; Proceedings of the 18th Annual Review, Brunswick, ME, July 28-Aug. 2, 1991 (A93-19582 06-38)