Browsing by Author "Holden, TM"

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    Comprehensive numerical analysis of a three-pass bead-in-slot weld and its critical validation using neutron and synchrotron diffraction residual stress measurements
    (Pergamon-Elsevier Science LTD, 2012-05-01) Muránsky, O; Smith, MC; Bendeich, PJ; Holden, TM; Luzin, V; Martins, RV; Edwards, L
    The current paper presents a finite element simulation of the residual stress field associated with a three pass slot weld in an AISI 316LN austenitic stainless steel plate. The simulation is split into uncoupled thermal and mechanical analyses which enable a computationally less expensive solution. A dedicated welding heat source modelling tool is employed to calibrate the ellipsoidal Gaussian volumetric heat source by making use of extensive thermocouple measurements and metallographic analyses made during and after welding. The mechanical analysis employs the Lemaitre-Chaboche mixed hardening model. This captures the cyclic mechanical response which a material undergoes during the thermo-mechanical cycles imposed by the welding process. A close examination of the material behaviour at various locations in the sample during the welding process, clearly demonstrates the importance of defining the correct hardening and high temperature softening behaviour. The simulation is validated by two independent diffraction techniques. The well-established neutron diffraction technique and a very novel spiral slit X-ray synchrotron technique were used to measure the residual stress-strain field associated with the three-pass weld. The comparison between the model and the experiment reveals close agreement with no adjustable parameters and clearly validates the used modelling procedure. Crown Copyright (C) 2011 Elsevier Ltd.
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    Evaluation of residual stresses in electron-beam welded Zr2.5Nb0.9Hf Zircadyne flange mock-up of a reflector vessel beam tube flange
    (Elsevier Science BV., 2013-07-01) Muránsky, O; Holden, TM; Kirstein, O; James, JA; Paradowska, AM; Edwards, L
    The dual-phase alloy Zr2.5Nb alloy is an important nuclear material, because of its use in current and possible use in future nuclear reactors. It is, however, well-known that Zr2.5Nb weldments can fail through a time-dependent mechanism called delayed hydride cracking which is typically driven by the presence of tensile residual stresses. With a view to understanding the development of residual stresses associated with Zr2.5Nb welds the current study focuses on the evaluation of the residual stresses in a mock-up of a reactor beam tube flange made from Zr2.5Nb0.9Hf. The present results suggests that, like ferritic welds which undergo a solid-state phase transformation upon welding, Zr2.5Nb0.9Hf welds also develop high tensile residual stresses in the heat-affected zone whereas the stresses closer to the weld tip are reduced by the effects of the beta -> alpha solid-state phase transformation. © 2013, Elsevier Ltd.
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    Residual stresses ICRS-10. 10th International Conference on Residual Stresses (ICRS 10), Sydney, Australia, 3-7 July, 2016
    (Materials Research Forum LLC, 2017) Holden, TM; Muránsky, O; Edwards, L
    This book presents the proceedings of the Tenth International Conference on Residual Stresses which was devoted to the prediction/modelling, evaluation, control, and application of residual stresses over a wide range of applications. New developments on stress-measurement techniques, on the modelling and prediction of residual stresses and on progress made in the fundamental understanding of the nature of residual stresses are highlighted. The proceedings offer an overview of the current understanding of how residual stresses affect the properties of materials, components and structures. © 2016 by the author(s)
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    Validation of a numerical model used to predict phase distribution and residual stress in ferritic steel weldments
    (Elsevier, 2014-08-15) Hamelin, CJ; Muránsky, O; Smith, MC; Holden, TM; Luzin, V; Bendeich, PJ; Edwards, L
    Numerical finite element analyses were combined with experimental observation of a single-pass autogenous beam weld in SA508 Gr.3 Cl.1 ferritic steel. Two weldment sets were prepared using different weld heat inputs, resulting in different post-weld residual stress and ferritic phase distributions. Neutron diffraction was employed to measure the residual stress distribution while microhardness measurements were used to measure the post-weld phase distribution in each weldment. In both cases, the numerical model accurately predicts the ferritic phase distribution and residual stress field. Model predictions illustrate how the higher cooling rates associated with a faster torch speed result in an increased martensite volume fraction within the weldment. Consideration of both the transformation kinetics and transformation plasticity are proven to significantly improve model accuracy when comparing measured and predicted residual stress profiles. © 2014, Acta Materialia Inc.