THE SLOW GROWTH AND RAPID PROPAGATION OF CRACKS

Abstract

The application of fracture mechanics to crackpropagation testing and fracture of high-strength, thin-section materials has been examined in relation to the development of a fracture failure from a small semi-elliptical, surface crack origin. In the absence of environmental influences, slow crack growth will be appreciable only if the ratio of the fracture toughness for the thickness under consideration, K sub c, to the so-called plane strain fracture toughness, K sub Ic, exceeds a certain value. An expression for this lower-bound value has been developed. If the ratio does not exceed the lower bound, direct calculations of fracture stress from the initial crack dimensions and the K sub Ic value can be made. Otherwise, the Irwin criterion that the critical crack length must exceed twice the section thickness applies. Environmental effects are important but are normally a factor only in material selection and not in fracture mechanics calculations. (Author)

Document Details

Document Type
Technical Report
Publication Date
May 17, 1961
Accession Number
AD0259739

Entities

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Continuum Mechanics
  • Fracture (Mechanics)
  • Materials
  • Mechanical Phenomena
  • Mechanical Properties
  • Mechanics
  • Peridynamics
  • Physics
  • Thickness
  • Toughness

Readers

  • Materials Science (Mechanical Engineering).