A THEORY OF FATIGUE BASED ON UNBONDING DURING REVERSED SLIP

Abstract

Fatigue is interpreted as a progressive unbonding of atoms as a result of reversal of slip caused by cyclic loading. The s-N equation is derived by using an exponential equation for crack growth and assuming that failure will occur when the crack reaches an arbitrary depth. The effect of stress on amplitude is introduced by using the term for inelastic strain from the Ramberg-Osgood empirical equation for the stress-strain curve. The resulting expressions agree with experimental data and afford a means of interpreting most of the known fatigue phenomena. They are also used to derive a new method of predicting the effects of loading of variable amplitude and to analyze the effects of a mean stress other than zero. The effects of notches are discussed in terms of stress-concentration factors.

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Document Details

Document Type
Technical Report
Publication Date
Nov 11, 1952
Accession Number
AD0422822

Entities

People

  • F. R. Shanley

Organizations

  • RAND Corporation

Tags

DTIC Thesaurus Topics

  • Aircrafts
  • Aluminum Alloys
  • Electron Microscopes
  • Engineering
  • Fatigue Tests (Mechanics)
  • Materials
  • Mechanical Working
  • Mechanics
  • Notch Sensitivity
  • Strain Hardening
  • Stress Analysis
  • Stress Concentration
  • Stress Strain Relations
  • Stresses
  • Surface Properties
  • Tensile Strength
  • Transition Temperature

Readers

  • Fluid Dynamics.
  • Structural Health Monitoring of Composite Structures.