Accession Number : ADA303810

Title :   Cyclic Debonding of Unidirectional Composite Bonded to Aluminum Sheet for Constant-Amplitude Loading.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Roderick, George L. ; Everett, Richard A., Jr. ; Crews, John H., Jr

PDF Url : ADA303810

Report Date : JAN 1976

Pagination or Media Count : 37

Abstract : Cyclic debonding rates were measured during constant-amplitude loading of specimens made of graphite/epoxy bonded to aluminum and S-glass/epoxy bonded to aluminum. Both room-temperature and elevated-temperature curing adhesives were used. Debonding was monitored with a photoelastic coating technique. The debonding rates were compared with three expressions for strain-energy release rate calculated in terms of the maximum stress, stress range, or a combination of the two. The debonding rates were influenced by both adherend thickness and the cyclic stress ratio. For a given value of maximum stress, lower stress ratios and thicker specimens produced faster debonding. Microscopic examination of the debonded surfaces showed different failure mechanisms both for identical adherends bonded with different adhesive and, indeed, even for different adherends bonded with identical adhesives. jg p3

Descriptors :   *COMPOSITE MATERIALS, *CYCLES, *ALUMINUM, *SHEETS, *AMPLITUDE, *ADHESIVES, *UNIDIRECTIONAL, STRESSES, LOADS(FORCES), FAILURE, GRAPHITE, STRAIN(MECHANICS), MICROSCOPY, SURFACES, COATINGS, LOW LEVEL, CURING, EPOXY COMPOSITES, PHOTOELASTICITY, JOINTS.

Subject Categories : Adhesives, Seals and Binders
      Inorganic Chemistry
      Laminates and Composite Materials
      Properties of Metals and Alloys
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE