Procedures for Precision Measurement of Fatigue-Crack-Growth-Rate Using Crack-Opening-Displacement Techniques.

Abstract

This paper describes experimental and analytical procedures whereby the conventional commercial fracture mechanics clip-gage can be used for precision measurement of fatigue-crack-growth-rate in compact tension specimens. Potential sources of error in measuring crack length via COD techniques are delineated. Comparisons are made among crack length data obtained via specimen surface observations and crack-opening-displacement (COD) techniques. Comparisons are also made among data analyzed by the secant and 7-point incremental polynomial methods. It is emphasized that COD techniques can enhance the accuracy of the secant method of data reduction. Step-loading procedures using COD techniques are described. Proposed amendments to ASTM E647-78T regarding incrementing of crack-length measurements via COD techniques are discussed. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Nov 19, 1979
Accession Number
ADA077670

Entities

People

  • George R. Yoder
  • L. A. Cooley
  • Thomas W. Crooker

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Accuracy
  • Alloys
  • Data Reduction
  • Fatigue Tests (Mechanics)
  • Fracture (Mechanics)
  • Hydrogen Embrittlement
  • Instrumentation
  • Intensity
  • Materials
  • Materials Testing
  • Measurement
  • Mechanics
  • Military Research
  • Precision
  • Test Methods
  • Thickness
  • Titanium Alloys

Fields of Study

  • Engineering

Readers

  • Computational Modeling and Simulation
  • Materials Science (Mechanical Engineering).
  • Systems Analysis and Design