The aim of this work was to analyze the effect of plasticity on residual stress measurement when the through thickness center-hole technique is used. The study investigated the effect of the most important loading, measuring, and material parameters, i.e., the residual stress intensity, the ratio between the principal residual stresses, the orientation of the strain-gage rusette with reference to the residual stress principal directions, the yield strength, and the strain hardening characteristics of the material. By means of a finite element simulation of the measurements, the errors that are usually produced by the direct use of ASTM E 837 (Test Method for Determining Residual Stresses by the Hole-Drilling Strain Gage Method) for the elaboration of the rosette strain gage readings was firstly determined by considering large enough ranges of the above-mentioned parameters to represent many conditions of practical concern. Afterwards it was shown that, at least within the limit of validity of the model, a considerable reduction of those errors can be obtained by using the proposed analytical procedure for elaborating the readings of a classical these elements strain-gage rosette. Moreover, the use of a new type of rosette with four radially oriented strain gages was proposed which could lead to further improvement of the measurement accuracy in any considered condition.

When the blind hole drilling method is used to evaluate high residual stresses in a metallic component, plastic relaxed strain can be produced in the hole region because of the stress concentration that causes the local stresses to reach yielding. By assuming a linear–elastic behaviour of the material, a significant error can result. The present paper analyses the phenomenon of the plasticity locally induced by the introduction of the hole and proposes a procedure to take into account its effects on the residual stress evaluation. The correcting procedure has been developed by elaborating a large database of elastic–plastic finite element analyses performed considering a wide range of material properties and testing parameters, including all the strain gauge rosettes commonly used. As plasticity induces non-linearity in the relationship between residual stress and relaxed strain, the superposition principle cannot be applied, so the correction is limited to uniform in-depth residual stress fields. However, four hole depths were considered and the related correcting procedures were provided. When variable through thickness residual stress is expected, and high residual stress is confined near the surface region, the correction procedure can be applied to an initial limited depth.