A Method for Determining X-ray Elastic Constants for the Measurement of Residual Stress

• Published in: Strain Vol. 39; no. 1; pp. 3 - 10
• Main Authors: Munsi, A. S. M. Y., Waddell, A. J., Walker, C. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.02.2003; Blackwell
• Subjects: calibration; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Measurement and testing methods; Measurement methods and techniques in continuum mechanics of solids; Physics; residual stress; Solid mechanics; Structural and continuum mechanics; vibratory stress relief; X-ray diffraction analysis; X-ray elastic constant; Elastic constant; Measurement; Calibration; X-ray elastic constant; X ray diffraction; Alloy steel; vibratory stress relief; X ray diffractometer; Spatial resolution; Residual stress; Measurement error; X-ray diffraction analysis; Bending test; Stress measurement
• ISSN: 0039-2103; 1475-1305
• DOI: 10.1046/j.1475-1305.2003.00044.x

: The X‐ray diffraction method is arguably the most convenient method of measuring residual stresses in terms of cost, spatial resolution, measurement time and the accuracy of measurement. The normal methods for calibrating X‐ray diffractometers are not conveniently applied to automated scanning systems, however, and so a new approach is required. In this study, a scanning X‐ray diffractometer was calibrated and the X‐ray elastic constant for a steel alloy was determined using a customised four‐point bending rig. The bending rig, in turn, was calibrated by dead loading. This study also described a simple alternative method for determining the X‐ray elastic constant, without the use of specialised software. After calibration, the error band of the diffractometer was found to be less than ±10 MPa. As this is ±5% of the yield stress for a typical steel, this level of accuracy was deemed to be acceptable for the measurement of residual stress.