Use of Symmetry for Residual Stress Determination

Use of Symmetry for Residual Stress Determination

R.C. Wimpory, M. Hofmann

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Abstract. Instrumental and certain sample characteristics can affect the detected Bragg peak shifts which are not related to the strain being measured. Three major effects can influence the measurement: the surface effect, where the instrumental gauge volume (IGV) is not fully immersed at a surface or interface, the grain size effect where there is random positioning of large grains in the sample within the gauge volume and the relative shift in position of the centre of gravity of measurement due to absorption of neutrons. All of these effects can be reduced/eliminated by making pairs of neutron diffraction measurements 180 degrees to each other at the same location. Results are presented from a round robin benchmark weldment, denoted TG6, from the European Network on Neutron Techniques Standardization for Structural Integrity (NeT). This is made from a nickel alloy which has large grains and strains and has a high neutron attenuation coefficient.

Keywords
Surface Effect, Absorption Effect, Neutron Diffraction, Aberrations, Round Robin, Standardization, Grain Size Effects, Plane Stress Calculations, Nickel Alloy

Published online 9/11/2018, 6 pages
Copyright © 2018 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: R.C. Wimpory, M. Hofmann, ‘Use of Symmetry for Residual Stress Determination’, Materials Research Proceedings, Vol. 6, pp 9-14, 2018

DOI: http://dx.doi.org/10.21741/9781945291890-2

The article was published as article 2 of the book Residual Stresses 2018

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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[6] “Precise measurement of steep residual strain gradients using neutron diffraction in strongly absorbing materials with chemical compositional gradients”, Robert C. Wimpory, Michael Hofmann, Vasileios Akrivos, Mike C Smith, Thilo Pirling and Carsten Ohms., Accepted for publication in Materials Performance and Characterization 2018
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