A Nonarbitrary Fatigue Crack Size Concept to Predict Total Fatigue Lives

Abstract

A method combining strain cycle fatigue and fracture mechanics concepts to predict a nonarbitrary crack initiation size, ai, is presented. The nonarbitrary crack size is used as a demarcation between fatigue crack initiation and propagation methods of analysis. Geometry, mean stress, and stress range all influence the value of ai. Five different geometries were analyzed and tested at various load levels and two load ratios. Constant amplitude loading and initial incremental overload are considered. Specimens of an aluminum alloy, Al 7075-T651, were tested in the as-machined condition. Correlations between the analytical life predictions and experimental values of life fell within a factor of two in most cases.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1979
Accession Number
ADA090596

Entities

People

  • D. F. Socie
  • Jo Dean Morrow
  • Peter Kurath

Organizations

  • University of Illinois Urbana–Champaign

Tags

Communities of Interest

  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Computational Science
  • Crack Propagation
  • Dynamics
  • Engineering
  • Fatigue Life
  • Finite Element Analysis
  • Fracture (Mechanics)
  • Geometry
  • Materials
  • Materials Engineering
  • Mechanical Properties
  • Mechanics
  • Plastic Explosives
  • Stresses
  • United States

Fields of Study

  • Engineering

Readers

  • Materials Science (Mechanical Engineering).