Residual Stress Changes in Fatigue.

Abstract

An investigation of transient time and cycle dependent stress and strain on Ti-6A1-4V titanium and 7475-T651 Al alloys was done to determine how great an effect transients at room temperature would have on fatigue life under cyclic conditions. The mechanical material response was modeled using viscoplasticity constitutive laws and Neuber's rule for notched members. Only small amounts of rate dependence was found, and the viscoplasticity models became stiff when rate dependence was low, causing numerical problems. Experimental verification was done for the local surface stresses in a notched member under load using advanced x-ray stress equipment. An anomalous surface behavior was observed, where the surface yielded before the bulk material. - X-ray measurements for a cycled notched member exhibited relaxation of mean stress and not relaxation of residual stress. (MM)

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Document Details

Document Type
Technical Report
Publication Date
Jan 15, 1994
Accession Number
ADA302323

Entities

People

  • Derome O. Dunn
  • M. P. Laurent
  • Norman E. Dowling

Organizations

  • Virginia Tech

Tags

Communities of Interest

  • Space
  • Weapons Technologies

DTIC Thesaurus Topics

  • Aircrafts
  • Computational Fluid Dynamics
  • Computational Science
  • Computer Programs
  • Creep
  • Crystal Lattices
  • Elastic Properties
  • Fatigue Life
  • Materials
  • Measurement
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Modulus Of Elasticity
  • Plastic Properties
  • Stress Strain Relations
  • Stresses

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.
  • Structural Dynamics.