1.1.1This test method specifies a hole-drilling procedure for determining in-plane residual stresses near the surface of an isotropic linearly elastic material. It is applicable to residual stress determinations where the stresses do not vary significantly across the diameter of the drilled hole. The measured stresses are the in-plane residual stresses that exist within the depth of the drilled hole. Stress sensitivity rapidly decreases with depth from the measured surface and deep interior stresses cannot be evaluated. The measured residual stresses are described as “uniform” if they remain approximately constant within the hole depth, “non-unifom” if they vary significantly.

1.1.2In general, “blind” holes are used, where the depth of the drilled hole and therefore the depth of the residual stress evaluation is less than the workpiece thickness. However, for a thin workpiece, it is also possible to do through-thickness measurements of uniform (membrane) stresses using a through-hole.

1.2.1This test method applies in cases where material behavior is linear-elastic. When near-yeild residual stresses are present, it is possible for local yielding to occur due to the stress concentration around the drilled hole. Satisfactory measurement results can be achieved providing the residual stresses do not exceed about 80 % of the material yield stress for blind-hole drilling and about 50 % of the material yield stress for through-hole drilling.

1.3.1The hole-drilling method is often described as “semi-destructive” because the damage that it causes is localized and often does not significantly affect the usefulness of the workpiece. In contrast, most other mechanical methods for measuring residual stresses substantially destroy the workpiece. Since hole drilling does cause some damage, this test method should be applied only in those cases either where the workpiece is expendable, or where the introduction of a small shallow hole will not significantly affect the usefulness of the workpiece.