This standard specifies the hole-drilling test method for measuring residual stresses near the surfaceof an isotropic liner-elastic material，which also covered measuring equipment，measuring proce-dures，the calibration of the stress calculation constant，the correction of the measurement error andso on.
Hole-drilling method is applicable to measure the stress state of the metal material where the internalstress gradient is small，the residual stress of this state which is almost a constant(uniform stress)may not change along the depth direction. Whereas the hole-drilling method can only determine theresidual stresses of the material near the surface，so the hole-drilling method only can measure thelocal residual stresses in the boundary of the hole.
2Normative references
The following referenced documents are indispensable for the application of this document.For da-ted references，only the edition cited applies.For undated references，the latest edition of the refer-enced document ( including any amendments) applies.
JJG 623，Verification Regulation of Resistance Strain Gauge lndicators
3Terms and Definitions
For the purposes of this documents，the following terms and definitions apply.
3.1
calibration constant for stresses
constant which connects the residual stresses and relaxed strain is related to the geometry of thestrain gauge，the location of the paste，and the shape and size of the hole
3.2
relieved strain
the change of strain before and after drilling hole on a structure with stress field
3.3
thin workpiece
work pieces whose material thickness is smaller compared with the hole and strain gage circle diame-ters
3.4
thick workpiece
work pieces whose material thickness is much large compared with the hole and strain gage circle di-ameters
3.5
intermediate thickness workpiece
the work piece whose material thickness is between thin work piece and thick work piece
3.6
high-speed hole-drilling
the processing technique with a rotational speed of tens of thousands rpm and the cutting removal isvery small
3.7
low-speed hole-drilling
the processing technique with a rotational speed of a few thousand rpm，particularly the electrichand drill
4 Symbols and Designations
The symbols and designations listed in the standard are shown in Table 1.
5Test Method
5.1Work piece
5.1.1A flat uniform surface area away from edges and other irregularities is chosen as the test lo-cation within the work piece of interest. Fig.1 schematically shows the residual stresses acting at thetest location at which a hole is to be drilled. These stresses are assumed to be uniform within the in-plane directions x and y.
NOTEln actuality，it is not necessary for the residual stresses to be uniform over such a large region The surface
strains that will be relieved by drilling a hole depend only on the stresses that originally existed at the boundariesof the hole. The stresses beyond the hole boundary do not affect the relieved strains，even though the strainsare measured beyond the hole boundary. Because of this，the hole-drilling method provides a very highly local-ized measurement of residual stresses.
5.1.2 Fig. 1a) shows the case where the residual stresses in the work piece are uniform in the depthdirection. The in-plane stresses are o x , o y and T y throughout the thickness. Uniform residual stressmeasurements can be made using this test method with“thin”work pieces and with“thick”workpieces.
5.1.3 Fig.1b) shows the case where the residual stresses in the work piece vary in the depth direc-tion. The calculation method described in this test method represents the stress profile as a staircaseshape，where the depth steps correspond to the depth increments used during the hole-drilling meas-urements. Within depth step k ， the in-plane stresses are(ox)k，( a ):and (T y )r.Non-uniform re-sidual stress measurements can be made using this test method only with “ thick"work pieces.
1Scope
This standard specifies the hole-drilling test method for measuring residual stresses near the surfaceof an isotropic liner-elastic material，which also covered measuring equipment，measuring proce-dures，the calibration of the stress calculation constant，the correction of the measurement error andso on.
Hole-drilling method is applicable to measure the stress state of the metal material where the internalstress gradient is small，the residual stress of this state which is almost a constant(uniform stress)may not change along the depth direction. Whereas the hole-drilling method can only determine theresidual stresses of the material near the surface，so the hole-drilling method only can measure thelocal residual stresses in the boundary of the hole.
2Normative references
The following referenced documents are indispensable for the application of this document.For da-ted references，only the edition cited applies.For undated references，the latest edition of the refer-enced document ( including any amendments) applies.
JJG 623，Verification Regulation of Resistance Strain Gauge lndicators
3Terms and Definitions
For the purposes of this documents，the following terms and definitions apply.
3.1
calibration constant for stresses
constant which connects the residual stresses and relaxed strain is related to the geometry of thestrain gauge，the location of the paste，and the shape and size of the hole
3.2
relieved strain
the change of strain before and after drilling hole on a structure with stress field
3.3
thin workpiece
work pieces whose material thickness is smaller compared with the hole and strain gage circle diame-ters
3.4
thick workpiece
work pieces whose material thickness is much large compared with the hole and strain gage circle di-ameters
3.5
intermediate thickness workpiece
the work piece whose material thickness is between thin work piece and thick work piece
3.6
high-speed hole-drilling
the processing technique with a rotational speed of tens of thousands rpm and the cutting removal isvery small
3.7
low-speed hole-drilling
the processing technique with a rotational speed of a few thousand rpm，particularly the electrichand drill
4 Symbols and Designations
The symbols and designations listed in the standard are shown in Table 1.
5Test Method
5.1Work piece
5.1.1A flat uniform surface area away from edges and other irregularities is chosen as the test lo-cation within the work piece of interest. Fig.1 schematically shows the residual stresses acting at thetest location at which a hole is to be drilled. These stresses are assumed to be uniform within the in-plane directions x and y.
NOTEln actuality，it is not necessary for the residual stresses to be uniform over such a large region The surface
strains that will be relieved by drilling a hole depend only on the stresses that originally existed at the boundariesof the hole. The stresses beyond the hole boundary do not affect the relieved strains，even though the strainsare measured beyond the hole boundary. Because of this，the hole-drilling method provides a very highly local-ized measurement of residual stresses.
5.1.2 Fig. 1a) shows the case where the residual stresses in the work piece are uniform in the depthdirection. The in-plane stresses are o x , o y and T y throughout the thickness. Uniform residual stressmeasurements can be made using this test method with“thin”work pieces and with“thick”workpieces.
5.1.3 Fig.1b) shows the case where the residual stresses in the work piece vary in the depth direc-tion. The calculation method described in this test method represents the stress profile as a staircaseshape，where the depth steps correspond to the depth increments used during the hole-drilling meas-urements. Within depth step k ， the in-plane stresses are(ox)k，( a ):and (T y )r.Non-uniform re-sidual stress measurements can be made using this test method only with “ thick"work pieces.
