ON THE MODALITY OF FATIGUE ENDURANCE DISTRIBUTIONS IN OFHC COPPER

Abstract

Altogether 884 OFHC copper specimens were fatigued under axial-load of 10, 12.7, 13, 14, 16.5 and 19 ksi constant amplitude and zero mean stress. Log-normal, extreme value, combinations of two truncated log-normal and truncated log-normal and extreme value distribution functions were fitted to the experimental endurance distributions. Furthermore, a mathematical dissection method was applied. The main results of this study are: the two endurance distributions observed with alloys could not be verified by polycrystalline (OFHC) copper; at stress levels around the lower knee the existence of two modes (bimodality) was apparent; at stress levels well above the knee, endurance distributions seem to become single log-normal, below the knee, extremal; the bimodality seems to be caused by a transition of predominance from one to another fatigue mechanism (Wood's F to H range transition). In conclusion, it may be said that the most important factor responsible for either the single, bimodal or two endurance distribution phenomenon seems to be the microstructural response of the tested material to the acting stress level.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1970
Accession Number
AD0708825

Entities

People

  • G. K. Korbacher

Organizations

  • University of Toronto

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Aluminum Alloys
  • Amplitude
  • Axial Loads
  • Data Science
  • Distribution Functions
  • Failure Mode And Effect Analysis
  • Fatigue Tests (Mechanics)
  • Frequency
  • Grain Boundaries
  • Hardening
  • Heat Treatment
  • Information Science
  • Materials
  • Normal Distribution
  • Standards
  • Strain Hardening
  • Temperature Gradients

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Statistical inference.