Acoustic emission analysis of woven graphite-epoxy composite materials

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6237573

Clinton, Jr, R G

The capability of acoustic emission to be successfully used as a means of detecting damaged or substandard composites was evaluated on the basis of analysis of data recorded during tensile tests on various graphite-epoxy laminates. Initially, the behavior of composites of differing resin contents, reinforced with unidirectional or woven graphite yarns was compared. Specimens containing fabrication defects, such as damaged fiber bundles and areas of matrix and void concentrations, were identifiable by their acoustic emission responses if such flaws influenced the ultimate strength. Selected specimens were examined using a scanning electron microscope; representative areas and defects were photographed. The objective of the subsequent research program was to determine whether laminates which had been exposed to a hygrothermal environment were qualitatively and quantitatively identifiable using acoustic emission. The objective was accomplished with a three-phased approach. It was essential that tensile specimens of a uniformly high quality be reproducible and that the acoustic emission responses of such specimens be consistent. Satisfaction of these critical requirements was demonstrated in the first phase. A stochastic model of event occurrences, developed in the second phase, was proposed as a means of quantifying the differences in the quality of the specimens in a probabilistic manner. In the third phase, the testing program was systematically evaluated in a preliminary test series to standardize the experimental methodology.

• Research Organization: Georgia Inst. of Tech., Atlanta (USA)
• OSTI ID: 6237573
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360303* -- Composite Materials-- Mechanical Properties-- (-1987)
42 ENGINEERING
420500 -- Engineering-- Materials Testing
ACOUSTIC EMISSION TESTING
ACOUSTIC TESTING
CARBON
COMPOSITE MATERIALS
DEFECTS
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
EPOXIDES
GRAPHITE
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
MICROSCOPY
MINERALS
MOISTURE
NONDESTRUCTIVE TESTING
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
SCANNING ELECTRON MICROSCOPY
TENSILE PROPERTIES
TESTING