Displacement Errors in the Application of Portable X-Ray Diffraction Stress Measurement Instrumentation
The role of residual stresses in the premature failure of metallic components has long been recognized. However, the most prevalent methods of measuring these stresses are at least partly, if not completely, destructive. This, as well as the availability of more rapid and portable x-ray diffraction instrumentation, has led to a renewed interest in this nondestructive residual stress measurement methodology.
This paper discusses the three most popular x-ray diffraction techniques for measuring residual stresses and describes theoretical, as well as experimental, results showing the sensitivity of two of the techniques to specimen-to-detector distance, i.e., displacement, errors. Further, the inherent theoretical advantage of the double-exposure over the single-exposure technique is derived. Theoretical and experimental evidence is then offered showing experimental difficulties in realizing this advantage. Finally, the inherent insensitivity of the single-exposure technique to displacement errors is demonstrated.
KeywordsResidual Stress Stress Measurement Iron Powder Detector Distance Residual Stress Measurement
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