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Uncertainty in flow stress measurements using X‐ray diffraction for sheet metals subjected to large plastic deformations
Author(s) -
Jeong Y.,
Gnäupel-Herold T.,
Iadicola M.,
Creuziger A.
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576716013662
Subject(s) - diffraction , monte carlo method , materials science , plasticity , viscoplasticity , flow stress , sheet metal , range (aeronautics) , stress (linguistics) , deformation (meteorology) , mechanics , optics , finite element method , composite material , physics , mathematics , thermodynamics , statistics , constitutive equation , strain rate , linguistics , philosophy
X‐ray diffraction techniques have been developed to measure flow stresses of polycrystalline sheet metal specimens subjected to large plastic deformation. The uncertainty in the measured stress based on this technique has not been quantified previously owing to the lack of an appropriate method. In this article, the propagation of four selected elements of experimental error is studied on the basis of the elasto‐viscoplastic self‐consistent modeling framework: (1) the counting statistics error; (2) the range of tilting angles in use; (3) the use of a finite number of tilting angles; and (4) the incomplete measurement of diffraction elastic constants. Uncertainties propagated to the diffraction stress are estimated by conducting virtual experiments based on the Monte Carlo method demonstrated for a rolled interstitial‐free steel sheet. A systematic report on the quantitative uncertainty is provided. It is also demonstrated that the results of the Monte Carlo virtual experiments can be used to find an optimal number of tilting angles and diffraction elastic constant measurements to use without loss of quality.