Accession Number : ADA302449

Title :   Interlaminar Flaw Propagation Mode II,

Corporate Author : DELAWARE UNIV NEWARK CENTER FOR COMPOSITE MATERIALS

Personal Author(s) : DiMondi, Vincent

PDF Url : ADA302449

Report Date : SEP 1980

Pagination or Media Count : 35

Abstract : The behavior of an interlaminar defect in a Hercules As/3501-6 graphite-epoxy (Gr/E) laminated beam subjected to flexural fatigue was investigated. Interlaminar defects were simulated by various sizes of Teflon disbonds implanted within the beam at the midsurface. Static flexural tests resulted in specimen flexure failure modes while fatigue loading produced stable interlaminar propagation of the defects due to the action of interlaminar shear stresses. Ultrasonic C-scan techniques were used to monitor defect propagation as a function of initial flaw size and the applied amplitude of the sinusoidal fatigue loading. Results are presented as plots of crack length versus number of cycles for each set of test conditions. Specimens which did not fail after 10 (exp 6) cycles in fatigue were tested for residual strength. Failure mode and micromechanical aspects of the flaw propagation results are discussed.

Descriptors :   *LAMINATES, *DEFECTS(MATERIALS), *GRAPHITE EPOXY COMPOSITES, BEAMS(STRUCTURAL), STIFFNESS, CRACKS, STRENGTH(MECHANICS), SHEAR STRESSES, FLEXURAL STRENGTH, BONDING, FATIGUE(MECHANICS), FAILURE(MECHANICS), MICROMECHANICS, ELONGATION, DELAMINATION, ULTRASONIC TESTS, CYCLIC LOADS, TETRAFLUOROETHYLENE RESINS, STRUCTURAL INTEGRITY.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE