SOME DIRECT OBSERVATIONS OF CUMULATIVE FATIGUE DAMAGE IN METALS.

Abstract

Metallographic techniques which have been used in previous work to study how fatigue damage develops in fatigue specimens subjected to cyclic strain at constant amplitude are extended to study of damage produced when cyclic strain is commenced in one range of amplitudes and continued in another. Reactions particularly studied have been those between what have been termed the H or large-amplitude range and the F or smallamplitude range as found in Fcc metal. It is shown how the type of damage produced by combination of H and F amplitudes differs from that which would be produced by either amplitude alone and depends upon the order in which they are applied. Damage is especially drastic if H cycles follow a sequence of F cycles which have established slip-zone fissures and on the basis of the observations suggestions are made on how this particular consequence may be avoided. (Author)

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1964
Accession Number
AD0610562

Entities

People

  • W. A. Wood
  • W. H. Reimann

Organizations

  • Columbia University

Tags

DTIC Thesaurus Topics

  • Acquisition
  • Amplitude
  • Data Acquisition
  • Observation
  • Sequences

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Materials Science (Mechanical Engineering).
  • Structural Health Monitoring of Composite Structures.