Measurement of Residual Strains around Coldworked Fastener Holes.

Abstract

Coldworking a fastener hole by pulling an oversize mandrel through it can improve its fatigue life because of the residual stresses generated around the hole. This report describes an experimental study of the residual strains around the hole and compares the results with existing theories. An industrial coldworking process is studied, and strains are determined close to the hole by measuring the distance between fiducial marks with an X-Y microscope and by the moire method. The strains near the hole are large (on the order of 5-10 percent) and inhomogeneous. None of the theories predict the strains well, though better agreement is obtained for thinner test specimens at positions away from the hole edge.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1976
Accession Number
ADA035147

Entities

People

  • William N. Sharpe Jr.

Organizations

  • Michigan State University

Tags

DTIC Thesaurus Topics

  • Agreements
  • Fasteners
  • Fatigue Life
  • Measurement
  • Mechanical Properties
  • Microscopes
  • Residual Stress
  • Residuals
  • Stresses

Fields of Study

  • Physics

Readers

  • Geodesy
  • Materials Science and Engineering.
  • Structural Health Monitoring of Composite Structures.