An Evaluation of the Hole-Relaxation Method of Determining Surface Residual Stresses

Abstract

The hole-relaxation technique of determining surface stresses was evaluated in load-induced linear stress fields as high as 90 percent of the yield strength of the material. Results indicate that an average accuracy of 5% is possible if strain gages 0.050 in. long are used at a distance of 5/16 in. from the center of a 7/16-in.-diameter hole. Test results also indicate that a depth of hole equal to one-half the hole diameter is sufficient to obtain all of the relaxation strains on the surface at which the hole is drilled. Tests were also conducted using 5/16-in.-diameter holes, and although good results were obtained, the overall degree of accuracy was not as great as with the 7/16-in.-diameter holes.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1963
Accession Number
AD0427360

Entities

People

  • Peter M. Palermo

Tags

DTIC Thesaurus Topics

  • Accuracy
  • Calibration
  • Diameters
  • Drilling
  • Fatigue Life
  • Gages
  • Heat Treatment
  • Laboratory Procedures
  • Laboratory Tests
  • Materials
  • Measurement
  • Mechanics
  • Model Basins
  • Residual Stress
  • Strain Gages
  • Stresses
  • Yield Strength

Readers

  • Geotechnical Engineering.
  • Materials Science (Mechanical Engineering).
  • Regression Analysis.