**List of symbols**

expressed as a function of Poisson's ratio and the diameter of the measured hole: only the approximate correction is provided. In this case, both the

*New Challenges in Residual Stress Measurements and Evaluation*

are far from those used to generate the calibration matrices reported in the

standard.

errors may be higher.

**13. Conclusions**

measured diameter (D = 1.88 mm) and the Poisson's ratio considered (n = 0.33 mm)

Finally, regarding the influence of the geometry of the strain gage rosette, the maximum deviation is approximately 2%. It represents the error due to use of a rosette that is different from the geometry envisaged in the standard. In this case, the rosette that was used is very similar to type B of the standard. In other cases, the

The paper describes some improvements in the hole-drilling test method for the analysis of residual stresses, developed to increase accuracy. These improvements have been introduced to overcome some limitations and correct some errors that

To make calculation of the distribution of non-uniform stresses more accurate, the evaluation of residual stresses was carried out by applying the general method, based on the influence functions, proposed by Beghini et al. [8, 9]. This approach is more extensive with respect to the integral method proposed by Schajer [13, 14] and can include a dependency on a higher number of parameters. This more general approach avoids some errors and removes some limitations in the evaluation of non-uniform residual stresses deriving from the application of the ASTM E837-13a standard, which is based on the Integral method. Ultimately, the Integral method can be considered as a special case of the influence function method in which

With this approach, some limitations of the standard can be overcome and, in

• For all strain gage rosettes available on the market, instead of just the A, B and

can derive from the direct application of the ASTM E837-13a standard.

particular, applicability of the hole-drilling test method is extended:

• When the thickness s of the workpiece is between 0.2D < s ≤ 1.0D.

• local plasticity, only in the case of blind holes and uniform stress

Furthermore, with this approach it will be possible to correct errors due to:

• approximate correction if the hole diameter and Poisson's ratio differ from the nominal value used for the evaluation of the calibration coefficients in ASTM

The paper also describes developments in measurement instrumentation with the use of automatic systems instead of manual systems and a procedure for evaluating measurement uncertainties in the case of non-uniform distribution, based on

• When eccentricity of the hole is greater than 0.004 D

piecewise constant functions are used as the basis.

C type rosettes [1],

• hole eccentricity

the GUM method.

**80**

• hole bottom chamfer



**References**

www.astm.org

2379-1365

[1] ASTM E837-13a. Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method. West Conshohocken, PA:

*DOI: http://dx.doi.org/10.5772/intechopen.90392*

[8] Beghini M, Bertini L, Mori LF. Evaluating non-uniform residual stress by the hole-drilling method with concentric and eccentric holes. Part I. Definition and validation of the influence functions. Strain. 2010;**46**: 324-336. DOI: 10.1111/j.1475-1305.2009.

[9] Beghini M, Bertini L, Mori LF. Evaluating non-uniform residual stress by the hole-drilling method with concentric and eccentric holes. Part II: Application of the influence functions to the inverse problem. Strain. 2010;**46**: 337-346. DOI: 10.1111/j.1475-1305.

[10] Beghini M, Bertini L, Santus C, Benincasa A, Bertelli L, Valentini E. Validazione sperimentale di una rosetta

[11] Nau A, Scholtes B. Experimental and numerical strategies to consider hole eccentricity for residual stress measurement with the hole drilling method. Materials Testing. 2012;**54**(5): 296-303. DOI: 10.3139/120.110330

[12] Ajovalasit A. Measurement of residual stresses by the hole-drilling method: influence of hole eccentricity.

[13] Barsanti M, Beghini M, Bertini L, Monelli BD, Santus C. First-order correction to counter the effect of eccentricity on the hole-drilling

integral method with strain-gage rosettes.

The Journal of Strain Analysis for Engineering Design. 2016;**51**(6):431-443.

DOI: 10.1177/0309324716649529

[14] Peral D, Correa C, Diaz M, et al. Measured strains correction for

Journal of Strain Analysis for Engineering Design. 1979;**14**:171-178

a 6 griglie per ridurre l'errore di eccentricità nella misura delle tensioni residue. In: Congresso AIAS XXXIX; Maratea (PZ). 2010. ISBN: 8860930749

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*Recent Advancements in the Hole-Drilling Strain-Gage Method for Determining Residual Stresses*

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Conshohocken; 2013. Available from:

[2] Valentini E, Bertelli L, Benincasa A. Improvements in the hole-drilling test method for determining residual stresses in polymeric materials. Materials Performance and

Characterization. 2018;**7**(4):446-464. DOI: 10.1520/MPC20170123 ISSN

[3] Schajer GS, Whitehead PS. Hole-Drilling Method for Measuring Residual Stress. Vermont, USA: Morgan &

[4] Schajer GS, Whitehead PS. Holedrilling and ring coring. In: Schajer GS, editor. Chapter 2 in Practical Residual

Chichester, UK: Wiley; 2013. pp. 29-64

[5] Schajer GS. Measurement of nonuniform residual stresses using the hole-

[6] Schajer GS. Measurement of nonuniform residual stresses using the holedrilling method. Part II—Practical application of the integral method. Journal of Engineering Materials and Technology. 1988;**110**:344-349

[7] Alegre JM, Díaz A, Cuesta II, Manso JM. Analysis of the influence of the thickness and the hole radius on the calibration coefficients in the holedrilling method for the determination of

non-uniform residual stresses. Experimental Mechanics. 2019;**59**:79. DOI: 10.1007/s11340-018-0433-0

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ASTM International, West

