14th International Conference on Shot Peening

Updated Theory Of The X-Ray Diffraction Residual Stress Measurement Comparing Cos-Alpha And Sin2psi Techniques – Biaxial Versus Triaxial Stress Field

Mohammed Belassel, James Pineault, Michael Brauss

PROTO MANUFACTURING LIMITED, 2175. Solar Crescent, Oldcastle. Ontario, Canada – email: mbelassel@protoxrd.com , Jpineault@protoxrd.com PROTO MANUFACTURING INC, 12350 Universal Drive, Taylor. Michigan, USA

Introduction

Different techniques have been developed for the measurement of residual stress using the x-ray diffraction method, however, significant differences in the results obtained have been observed depending on which specific technique is used and how it is applied in practice. If incorrectly applied, certain techniques may produce erroneous results under certain conditions. Observed differences in the results obtained using specific techniques (e.g. sin2Psi vs. CosAlpha) may depend upon the collection parameters selected, the measurement conditions and geometry of the test article, the material condition and microstructure, and the processes applied that imparted the residual stress field present. A clear understanding of the strengths and weaknesses associated with the various techniques is thus a requirement in assessing their applicability to the accurate measurement of residual stress on shot peened and other components using the x-ray diffraction method.

Objectives

This paper will illustrate these differences based on simulation and experiment for all stress tensor components. Emphasis on the measurement of residual stress versus applied stress will be developed, and the current stress standards will be assessed.