Preliminary Investigation of Crack Arrest in Composite Laminates Containing Buffer Strips.

Abstract

The mechanical properties of some hybrid buffer strip laminates and the crack arrest potential of laminates containing buffer strips were determined. The hybrid laminates consisted of graphite with either S-glass, E- glass, or Kevlar. Unnotched tensile coupons and center-cracked fracture coupons were tested. Elastic properties, complete stress/strain curves, and critical stress intensity values are given. The measured elastic properties compare well with those calculated by classical lamination theory for laminates with linear stress/strain behavior. The glass hybrids had more delamination and higher fracture toughness than the all-graphite or the Kevlar hybrid. The buffer strip laminates for the crack arrest study were fabricated using six layers of woven fiberglass cloth and polyester resin. Each laminate contained two buffer strips formed by interrupting the cloth and weakening the inner laminar bond with teflon coated glass fabric. Woven Kevlar cloth was also used in some laminates in place of the fiberglass buffer strips.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1978
Accession Number
ADA301986

Entities

People

  • J. Goree

Organizations

  • Clemson University

Tags

Communities of Interest

  • Air Platforms
  • C4I

DTIC Thesaurus Topics

  • Composite Materials
  • Delamination
  • Elastic Properties
  • Epoxy Laminates
  • Graphitic Materials
  • Laminates
  • Materials
  • Materials Processing
  • Materials Science
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Notch Sensitivity
  • Resins
  • Stress Intensity Factors
  • Stresses
  • Three Dimensional

Readers

  • Polymer Science and Engineering.
  • Structural Health Monitoring of Composite Structures.