Bragg-edge elastic strain tomography for in situ systems from energy-resolved neutron transmission imaging

Technological developments in high resolution time-of-flight neutron detectors have raised the prospect of tomographic reconstruction of elastic strain fields from Bragg-edge strain images. This approach holds the potential to provide a unique window into the full triaxial stress field within solid samples. While general tomographic reconstruction from these images has been shown to be ill-posed, an injective link between measurements and boundary deformations exists for systems subject to in situ applied loads in the absence of residual stress. Recent work has provided an algorithm to achieve tomographic reconstruction for this class of mechanical system. This letter details an experimental proof-of-concept for this algorithm involving the full reconstruction of a biaxial strain field within a non-trivial steel sample. This work was carried out on the RADEN energy resolved neutron imaging instrument within the Japan Proton Accelerator Research Complex, with validation through Digital Image Correlation and constant wavelength neutron strain scans.

[1]  J. Cohen,et al.  Residual Stress: Measurement by Diffraction and Interpretation , 1987 .

[2]  Mark R. Daymond,et al.  Strain imaging by Bragg edge neutron transmission , 2002 .

[3]  Michael H. Meylan,et al.  Bragg Edge Neutron Transmission Strain Tomography in Granular Systems , 2016 .

[4]  Philip J. Withers,et al.  Engineering applications of Bragg-edge neutron transmission , 2002 .

[5]  Jason McPhate,et al.  Transmission Bragg edge spectroscopy measurements at ORNL Spallation Neutron Source , 2010 .

[6]  Anand Asundi,et al.  Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review , 2009 .

[7]  Jason McPhate,et al.  High resolution Bragg edge transmission spectroscopy at pulsed neutron sources: Proof of principle experiments with a neutron counting MCP detector , 2011 .

[8]  Hubert W. Schreier,et al.  Image Correlation for Shape, Motion and Deformation Measurements: Basic Concepts,Theory and Applications , 2009 .

[9]  J. McPhate,et al.  Energy-Resolving Neutron Transmission Radiography at the ISIS Pulsed Spallation Source With a High-Resolution Neutron Counting Detector , 2008, IEEE Transactions on Nuclear Science.

[10]  Ryan R. Dehoff,et al.  Neutron Characterization for Additive Manufacturing , 2013 .

[11]  B. Abbey,et al.  Reconstruction of axisymmetric strain distributions via neutron strain tomography , 2012 .

[12]  John Banhart,et al.  Neutron Bragg-edge-imaging for strain mapping under in situ tensile loading , 2011 .

[13]  J. R. Granada,et al.  The bragg lineshapes in time-of-flight neutron powder spectroscopy , 1982 .

[14]  B. Abbey,et al.  Neutron Strain Tomography using the Radon Transform , 2015 .

[15]  M. Prime.  Cross-sectional mapping of residual stresses by measuring the surface contour after a cut , 2001 .

[16]  Francesco Grazzi,et al.  Investigation of microstructure in additive manufactured Inconel 625 by spatially resolved neutron transmission spectroscopy , 2016, Science and technology of advanced materials.

[17]  Jason McPhate,et al.  High‐Resolution Strain Mapping Through Time‐of‐Flight Neutron Transmission Diffraction with a Microchannel Plate Neutron Counting Detector , 2012 .

[18]  V. Hauk,et al.  Structural and residual stress analysis by nondestructive methods : evaluation, application, assessment , 1997 .

[19]  William R B Lionheart,et al.  Diffraction tomography of strain , 2015 .

[20]  Vladimir Luzin,et al.  Bragg-edge neutron transmission strain tomography for in situ loadings , 2016 .

[21]  Michael E. Fitzpatrick,et al.  Analysis of Residual Stress by Diffraction using Neutron and Synchrotron Radiation , 2003 .

[22]  D. Penumadu,et al.  Time-of-flight neutron imaging for spatially resolved strain investigations based on Bragg edge transmission at a reactor source , 2012 .

[23]  B. Abbey,et al.  Feasibility study of neutron strain tomography , 2009 .