The Effect of Autofrettage on Fatigue Crack Propagation in Externally Flawed Thick-walled Disks.

Abstract

The effect of the autofrettage residual stress distribution on the crack growth rate in externally flawed thick-walled disks has been investigated. The crack growth rate was modeled by using the Paris power law relation. Stress intensity factors were calculated for internally pressurized, externally flawed, non-autofrettaged cylinders, by an approximate technique and with the use of the NASTRAN finite element computer program. A simple experiment was devised to determine the effect of autofrettage on crack growth rate. The test involved diametrically loading thin disks, cut from autofrettaged cylinders, NASTRAN was used to determine the stress intensity factors for this loading geometry. The experimentally observed results show that autofrettage increases the crack growth rate in externally flawed cylinders, but the test did not supply sufficient data to mathematically model the increase. The faster crack growth rate is believed to be caused by the local relaxation of the tensile autofrettage residual stresses due to large plastic zones accompanying crack growth. (Author)

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1977
Accession Number
ADA040229

Entities

People

  • J. A. Kapp

Organizations

  • United States Army Armament Research, Development and Engineering Center

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Autofrettage
  • Bending Stress
  • Crack Propagation
  • Cracks
  • Engineering
  • Equations
  • Fatigue Life
  • Fracture (Mechanics)
  • Geometry
  • Internal Pressure
  • Materials
  • Mechanics
  • Pressure Distribution
  • Residual Stress
  • Stress Intensity Factors
  • Stresses
  • Thickness

Readers

  • Materials Science (Mechanical Engineering).
  • Mechanical Engineering/Mechanics of Materials.
  • Structural Dynamics.