Accession Number:

ADA279763

Title:

Detection of Environmental Deterioration in Fiber Reinforced Composites by FT-Raman Spectroscopy. Phase 1

Descriptive Note:

Final rept. 30 Jul 1993-30 Apr 1994

Corporate Author:

ADVANCED FUEL RESEARCH INC EAST HARTFORD CT

Report Date:

1994-05-01

Pagination or Media Count:

47.0

Abstract:

A number of advanced fiber reinforced organic matrix composites are being developed and applied in the aerospace industry. In these applications, the composites may be exposed to a variety of harsh environments, which may induce chemical and physical changes in the composite material, and ultimately lead to component failure. The successful use of these composites, therefore, requires methods to reliably detect and assess these changes. During this Phase I Program, a fiber optic based Fourier transform Raman spectrometer was specifically developed to perform nondestructive evaluation of environmentally damaged composites. Specifically, graphite and Kevlar reinforced epoxy and polyimide composite samples were subjected to thermal cycling, moisture exposure and ultraviolet irradiation. Three point flexure tests were used to measure flexural strength, flexural modulus, failure strain and failure load to assess induced mechanical property changes in the composites. Reflectance infrared spectra of the sample surfaces, as well as transmission infrared spectra of evolved gas phase chemical species were used to further characterize these changes.

Subject Categories:

  • Aircraft
  • Laminates and Composite Materials
  • Atomic and Molecular Physics and Spectroscopy
  • Environmental Health and Safety

Distribution Statement:

APPROVED FOR PUBLIC RELEASE