Toughening of Graphite-Epoxy Composites by Interlaminar Perforated Mylar (trade name) Films.

Abstract

Fracture and notch-strength tests of graphite-epoxy composites have shown that unidirectional lay-ups generally exhibit longitudinal cracking before failure, whereas multidirectional lay-ups fail transversely with little longitudinal cracking. A simple qualitative analysis suggested that the higher matrix shear stresses in unidirectional materials cause the longitudinal cracking, and that this cracking is responsible for the higher toughness of unidirectional composites. In a series of comparative tests, the interlaminar strength of multidirectional composites was reduced by placing perforated Mylar films between laminae; tests on notched and slotted specimens showed that the inter-laminar films promoted delamination and longitudinal cracking near the notches and that, as a result, toughness, notch strength, and impact strength were substantially increased. (MM)

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1978
Accession Number
ADA301743

Entities

People

  • Wolf Elber

Organizations

  • Langley Research Center

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Biocomposites
  • Composite Materials
  • Delamination
  • Epoxy Composites
  • Failure Mode And Effect Analysis
  • Fibers
  • Films
  • Graphite Epoxy Composites
  • Graphitic Materials
  • Impact Strength
  • Impact Tests
  • Materials
  • Notch Sensitivity
  • Shear Strength
  • Shear Stresses
  • Stresses
  • Toughness

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Reinforced Composite Materials
  • Structural Health Monitoring of Composite Structures.