Accession Number : ADA301730

Title :   Ultrasonic Attenuation as an Indicator of Fatigue Life of Graphite/Epoxy Fiber Composite.

Descriptive Note : Contract rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s) : Williams, James H., Jr ; Doll, Beth

PDF Url : ADA301730

Report Date : DEC 1979

Pagination or Media Count : 22

Abstract : Microscopic imperfections in graphite fiber epoxy composites may be introduced during both fabrication and service. The tendency of graphite fiber composites to fall in a quasi-brittle mode (as defined by the absence of a substantial nonlinear region in the stress-strain curve) makes these composites more sensitive than many metals to microscopic imperfections. In fatigue, failure has been described as being "like sudden death; that is, the fatigue failure occurs without any visible evidence of damage". Thus, any means of nondestructively monitoring fatigue damage or predicting fatigue behavior of graphite fiber composites is likely to enhance their effective use. The purpose of this report is to present the results of an experimental study to investigate the ultrasonic attenuation and velocity as a function of the fatigue state of a graphite fiber composite subjected to transfer compression-compression loading.

Descriptors :   *FATIGUE LIFE, *ULTRASONICS, *ATTENUATION, *GRAPHITE EPOXY COMPOSITES, COMPRESSION, STRESS STRAIN RELATIONS, METALS, DAMAGE, MONITORING, COMPOSITE MATERIALS, CARBON FIBERS, BRITTLENESS, NONLINEAR SYSTEMS, VISIBILITY, FATIGUE(MECHANICS), FAILURE(MECHANICS), GRAPHITED MATERIALS.

Subject Categories : Laminates and Composite Materials
      Physical Chemistry
      Acoustics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE