HOLE-DRILLING STRAIN-GAGE METHOD OF MEASURING RESIDUAL STRESSES.
NAVAL RESEARCH LAB WASHINGTON D C
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The hole-drilling, strain-gage method of measuring residual stresses in elastic materials has been termed semidestructive because of the use of holes of very small diameters. The method permits the magnitudes and principal directions of residual stresses at the hole location to be determined. This is accomplished by means of an empirically determined quantitative relation between the magnitudes and directions of the principal stresses and the strain relaxation about the hole as the hole is drilled. This relation was obtained for a nondimensional model of the hole-gage assembly in order to make the results independent of hole size. A generalization was postulated to extend the use of this calibrated solution to the measurement of residual stresses in all elastic, isotropic materials. Author