Evaluation of Cod Compliance Determined Crack Growth Rates.

Abstract

Fatigue crack growth rate studies were conducted on sixteen X7091 aluminum specimens. Crack growth rates were determined by visual crack length measurements and crack-opening-displacement (COD) compliance measurement. The curves of crack growth rate versus stress intensity factor from COD compliance measurements were compared to the optical crack growth rate results which were determined by following ASTM E647 Standard Test Method for Constant-Load-Amplitude Fatigue Crack Growth Rates Above 10 to the 8th power m/Cycle. Differences between the growth rates from the two methods are discussed in terms of potential errors in the evaluation of variables used in the data collection and analysis. The use of handbook elastic modulus value has been found to be a source of significant error. The use of an effective modulus value calculated from the initial visual crack length is recommended. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1984
Accession Number
ADA144037

Entities

People

  • D. C. Maxwell
  • J. P. Gallagher
  • N. E. Ashbaugh

Organizations

  • University of Dayton

Tags

Communities of Interest

  • Air Platforms
  • C4I
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Accuracy
  • Acquisition
  • Aeronautical Laboratories
  • Air Force
  • Aluminum
  • Contracts
  • Data Acquisition
  • Intensity
  • Materials
  • Materials Laboratories
  • Measurement
  • Modulus Of Elasticity
  • Plastic Explosives
  • Standards
  • Stress Intensity Factors
  • Test And Evaluation
  • Test Methods

Readers

  • Instructional Design and Training Evaluation.
  • Materials Science (Mechanical Engineering).