Browsing by Author "Bouchard, PJ"
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- ItemEuropean Network on Neutron Techniques Standardization for Structural Integrity - NeT.(American Society of Mechanical Engineers (ASME), 2008-07-27) Ohms, C; Martins, RV; Uca, O; Youtsos, AG; Bouchard, PJ; Smith, M; Keavey, M; Bate, SK; Gilles, P; Wimpory, RC; Edwards, LThis paper provides an overview over the work of the European Network on Neutron Techniques Standardization for Structural Integrity (NeT). The network involves some 35 organisations from industry and academia and these partners undertake the application of modern experimental and numerical techniques to problems related to the structural integrity of components, mainly relevant to nuclear applications. While being built around neutron scattering techniques, which are predominantly applied for analyses of welding residual stresses, one of the major strengths of the consortium is the diversity in available experimental and numerical techniques. In the residual stress area, for example, many types of materials characterizations testing, several methods for residual stress analysis, including neutron and X-ray diffraction, deep hole drilling, the contour method and others, and many different ways of numerical analysis employing several commercially available FEM codes can be covered by the partners. Currently the network has embarked on five different Task Groups. Four of these are dealing with welding residual stress assessment, and one applies Small Angle Neutron Scattering for studying thermal ageing processes in duplex stainless steels used for reactor core internals. The work already performed in the context of NeT and the envisaged investigations for the ongoing Task Groups are briefly outlined in this paper. The aim is to give the reader a comprehensive overview of the work of NeT and to shed some light on the potential present in this kind of collaborative effort. © The American Society of Mechanical Engineers
- ItemFull field measurement of plastic flow properties in a multi-pass austenitic stainless steel weld specimen.(American Society of Mechanical Engineers (ASME), 2008-07-27) Ganguly, S; Turski, M; Fitzpatrick, ME; Edwards, L; Smith, MC; Bouchard, PJKnowledge of constitutive material stress strain properties is important for reliable prediction of weld residual stress fields using analytical stress simulation techniques. The present work investigates the surface stress strain behaviour of a 3-pass groove-welded austenitic stainless steel disc. A relatively novel electronic speckled pattern interferometry (ESPI) technique was employed to monitor the surface deformation pattern across the weld, HAZ and parent metal of the specimens with very high spatial resolution. The deformation data was then analysed to determine the constitutive stress-strain property across the welded specimen. The analyses show very different patterns of proof stress variation across the pass I and pass III weld metal. The accumulated plastic strain in the pass I weld metal resulted in an increase of the 0.2% PS value by 175 MPa. © 2008 ASME
- ItemThe incremental contour method using asymmetric stiffness cuts(Elsevier, 2021-01-01) Achouri, A; Hosseinzadeh, F; Bouchard, PJ; Paddea, S; Muránsky, OAn incremental Contour Method (iCM) of residual stress measurement is proposed where residual stresses in the body of interest are sequentially reduced by successive contour cuts and the risk of stress re-distribution plasticity is mitigated or eliminated. The cutting-induced plasticity is known to cause significant inaccuracies when trying to measure the near-yield residual stresses using a conventional single cut contour method. The iCM procedure implements a new displacement data processing approach for the general case of sectioning at an arbitrary plane where the cut parts do not possess mirror-symmetric elastic stiffness. The basis for the new asymmetric stiffness data analysis approach is presented and the accuracy of the new method demonstrated using both numerical and experimental case studies. © 2020 The Authors. Published by Elsevier Ltd.
- ItemMitigating cutting-induced plasticity in the contour method, part 1: experimental(Elsevier B.V., 2016-09-01) Hosseinzadeh, F; Traore, Y; Bouchard, PJ; Muránsky, OApplication of the contour method for the measurement of weld residual stresses (WRS) is prone to inaccuracy due to plastic deformation resulting from the redistribution of typically high (close to yield) WRS during the cutting process. The current work, seeks ways to mitigate cutting-induced plasticity by controlling stress redistribution through optimisation of the contour cutting configuration. The idea of using a stress-informed fracture mechanics approach to find the optimal cutting configuration is introduced. The level of plasticity associated with different cutting configurations is then assessed, allowing control of the location and magnitude of cutting-induced plasticity to occur during the cutting process. A conventional edge-crack cutting configuration is compared with a proposed double-embedded cutting configuration by measuring the longitudinal WRS in two three-pass slot weld specimens (NeT TG4) produced using identical weld procedures. The experimental results show that a novel double-embedded cutting configuration leads to greater accuracy in WRS measurements relative to conventional edge-crack cutting configurations at the expense of higher levels of plasticity being introduced local to small ligaments. © 2016 Published by Elsevier Ltd.
- ItemModern and historical engineering components investigated by neutron diffractionon ENGIN-X(Japan Society of Mechanical Engineers, 2012-06-29) Paradowska, AM; Tremsin, A; Kelleher, JF; Zhang, SY; Paddea, S; Burca, G; James, JA; Ahmed, R; Faisal, NH; Festa, G; Andreani, C; Civita, F; Bouchard, PJ; Krockelman, W; Fitzpatrick, ME; Grazzi, FThe ENGIN-X beamline is mainly used to determine residual strains/stresses deep within the interior of bulk engineering components. It is mainly used by scientists and engineers for the development of modern engineering processes and structural integrity investigations. ENGIN-X diffraction and transmission mode can be a very useful tool to measure strain, phase transitions, texture and material composition in spatial resolution in historical or archaeological artifacts and modern materials. The complexity of the shapes and sizes of the samples measured on ENGIN-X varies significantly between experiments, and this required the development of better planning, simulation and control software, SScanSS. In this paper an overview of recent developments in strain scanning on ENGIN-X and a highlight of current scientific research are presented. © 2012 The Japan Society of Mechanical Engineers
- ItemNeutron diffraction residual stress measurements in a 316L stainless steel bead-on-plate weld specimen.(Elsevier, 2009-01) Pratihar, S; Turski, M; Edwards, L; Bouchard, PJThe distribution of residual stress in three orthogonal directions has been measured within a Type 316L austenitic stainless steel bead-on-plate weld specimen. Neutron diffraction was employed using the ENGIN-X instrument, located at the ISIS spallation facility of the Rutherford Appleton Laboratory, UK. A stress-free lattice parameter reference value was determined from a small cube, extracted from a far corner of the plate. A high magnitude of tensile residual stress was found along the weld bead in the longitudinal and transverse directions. The distributions of stress along through-thickness lines at the weld bead nominal start and stop locations and at the mid-length position showed an almost identical stress variation. However, a map of measured residual strain in the transverse direction beneath the weld bead revealed a concentration of strain located several millimetres before the nominal weld stop position where through-wall stress profiles were measured. © 2009, Elsevier Ltd.
- ItemSpatially resolved materials property data from a uniaxial cross-weld tensile test(American Society of Mechanical Engineers (ASME), 2009-12) Turski, M; Smith, MC; Bouchard, PJ; Edwards, L; Withers, PJApplication of electronic speckle pattern interferometry (ESPI) is described to measure the spatial variation in monotonic tensile stress-strain properties along “cross-weld” specimens machined from a stainless steel three-pass welded plate. The technique, which could also be done with digital image correlation, was applied to quantify how the material 0.2%, 1%, 2%, 5%, 10%, and 20% proof stress varied with distance from the center-line of the weldment for parent and weld material associated with the first and final passes. The stress-strain curves measured by the ESPI method correlated closely with stress-strain data measured using conventional test specimens. The measured results are consistent with the hypothesis that thermo-mechanical cycles associated with the welding process work harden previously deposited (single-pass) weld metal and the surrounding parent material. The stress-strain response of the heat affected zone adjacent to the first weld pass is consistent with an accumulated (equivalent monotonic) plastic strain of 6.5% and that of the first pass weld bead was consistent with an accumulated plastic strain of approximately 4% greater than the state of the final pass weld metal. © 2009, American Society of Mechanical Engineers (ASME)