The ASTM E837 (‚ÄúStandard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method‚ÄĚ) is the only complete standard on residual stresses available all over the world. The last version has been published at the end of 2020, introducing several changes and improvements.
The ASTM E837-20 standard specifies the complete hole-drilling procedure to determine residual stress profiles near the surface of an isotropic linearly elastic material: it includes the requirements in term of equipment specifications, practical step-by-step information about the drilling and acquisition process and also calculation algorithms and their related coefficients for the evaluation of residual stress.
The ASTM E837 standard includes different calculation strategies as listed below:
‚ÄúUniform‚ÄĚ stress distribution if the stresses are expected to remain approximately constant with depth both for “Thick” and “Intermediate” thickness workpieces
‚ÄúNon-uniform‚ÄĚ stress distribution when the stresses may vary significantly with depth both for “Thick” and “Intermediate” thickness workpieces
The MTS3000-Restan system, developed and patented by SINT Technology, is fully compliant with the ASTM E837-20 standard; due to many years of experience in the field of strain gauge measurements and in software and mechanical design engineering, it also guarantees to carry out excellent residual stress analysis in all the possible test conditions.
Moreover, the dedicated EVAL software for the analysis of residual stress by hole-drilling includes all the required features necessary for the calculation, and it extends the validity of the method thanks to the cooperation with the most important Universities worldwide. Their Research Institutes developed and improved calculation methods, theoretical models for the correction of the main source of errors (as eccentricity, local plasticity and intermediate thickness) and specific algorithms for the evaluation of the measurement uncertainty.