ORCID Profile
0000-0001-7526-6020
Current Organisations
Open University
,
Australian Nuclear Science and Technology Organisation
,
Monash University
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Ceramics | Materials engineering | Other Physical Sciences | Manufacturing Engineering | Solid State Chemistry | Manufacturing Processes and Technologies (excl. Textiles) | Ceramics | Characterisation Of Macromolecules | Materials Engineering | Metals and Alloy Materials | Numerical Modelling and Mechanical Characterisation | Materials Engineering Not Elsewhere Classified | Alloy Materials | Metals and alloy materials | Instruments And Techniques |
Ceramics | Other | Clinical health not specific to particular organs, diseases and conditions | Metals (composites, coatings, bonding, etc.) | Structural Metal Products | Other non-ferrous metals (e.g. copper,zinc) | Scientific instrumentation
Publisher: Elsevier BV
Date: 07-2018
Publisher: ASMEDC
Date: 2010
Abstract: British Energy (BE) has funded a large work programme to assess the possible impact of primary water stress corrosion cracking on dissimilar metal welds in the primary circuit of the Sizewell ‘B’ pressurised water reactor. This effort has included the design and manufacture of representative pressuriser safety/relief valve nozzle welds both with and without a full structural weld overlay, multiple residual stress measurements on both mock-ups using the deep hole and incremental deep hole methods, and a number of finite element weld residual stress simulations of both the mock-ups and equivalent plant welds. Three organisations have performed simulations of the safety/relief valve nozzle configuration: Westinghouse, Engineering Mechanics Corporation of Columbus (EMC2) and the Australian Nuclear Science and Technology Organisation (ANSTO). The simulations employ different welding heat input idealisations, make different assumptions about manufacturing history, and use a variety of different material constitutive models, ranging from simple bilinear kinematic hardening to a full mixed isotropic-kinematic formulation. The availability of both high quality measurements from well characterised mock-ups, and a large matrix of simulations, offers the opportunity for a “mini-round-robin” examining both the accuracy and key solution variables of dissimilar metal weld finite element simulations. This paper is one of a series at this conference that examine various aspects of the BE work programme. It describes the detailed finite element simulation of the mock-ups performed by BE and ANSTO. This makes use of the extensive mock-up manufacturing records to perform a detailed pass-bypass simulation of the entire manufacturing process from initial nozzle buttering through to completion of the safe end to pipe weld. The thermal simulation makes use of a dedicated welding heat source modelling tool to derive Gaussian volumetric heat source parameters from the welding records, and the mechanical simulation employs isotropic, kinematic and mixed isotropic-kinematic material constitutive models. Additional sensitivity studies examine sensitivity to manufacturing history and physical properties such as expansion coefficient mismatch.
Publisher: Elsevier BV
Date: 03-2012
Publisher: Elsevier BV
Date: 09-2008
Publisher: Elsevier BV
Date: 12-2008
Publisher: ASMEDC
Date: 2010
Abstract: A critical requirement for both next generation conventional and nuclear plants is the development of simplified inelastic design and fitness for purposes procedures that give a reasonably accurate prediction of the complex multi-axial time dependent stress strain behavior. The accumulation of this inelastic strain in the form of coupled creep-fatigue damage over time is one of the principal damage mechanisms which will eventually lead to crack initiation in critical high temperature equipment. Two main procedures that address creep-fatigue loading are generally used, either a time fraction or a ductility exhaustion approach. It is generally accepted that these methods enable conservative predictions within a factor of 2 to 3 and hence are reliable methods for code based design and fitness for purpose type assessments. However, for complex cycles, this may not be the case, for ex le prior relaxation cycles are found to accelerate the creep rupture of the material with the result that a significant reduction in creep life can be observed. An investigation was undertaken into the influence of prior relaxation on resultant failure using a typical low alloy ferritic power station steel. Both time based and strain based methods were used to predict the damage caused by the stress relaxation cycles followed by operation at steady state. The predictions found that while ductility exhaustion methodologies based on mean properties where adequate in predicting the failure life, time fraction methods were found to be extremely non-conservative for mean properties and only lower bound solutions provided an estimate of remaining creep life. The Monkman-Grant approach resulted in predictions that erred on the conservative side. The results have implications for both current and future conventional and nuclear power stations as it may be difficult for time based approaches to accurately account for complex cycling, shakedown conditions or stress relaxation at welds.
Publisher: Elsevier BV
Date: 04-2002
Publisher: ASMEDC
Date: 2010
Abstract: In this paper finite element simulation and neutron diffraction measurements are employed to assess the residual stresses in an AISI 316LN austenitic stainless steel plate containing a three-pass finite length weld in a machined slot. This work forms a part of the Task Group 4 (TG4) measurement and simulation round robin being undertaken by the NeT European network. Finite element (FE) simulations were carried out using the FEAT-WMT and ABAQUS commercial finite element packages. The welding process was modelled both using a 3D moving-heat source (MHS) which is spatially correct but computationally expensive and using a simplified “block-dumped” methodology (BD) in which an entire weld bead is deposited simultaneously. This does not reproduce the effects of welding torch movement, but is computationally less expensive. The mechanical analyses used combined isotropic-kinematic material constitutive models with a two-stage annealing functionality to remove plastic strain accumulated at high temperatures. The finite element predictions of weld residual stress are compared with neutron diffraction measurements obtained on the KOWARI diffractometer at the OPAL reactor at ANSTO.
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 04-1994
Publisher: Springer Science and Business Media LLC
Date: 04-1998
Publisher: Crossref
Date: 12-2001
Publisher: Elsevier BV
Date: 07-2004
Publisher: SAGE Publications
Date: 05-1997
Abstract: The optical method of caustics is an experimental technique which, particularly when used in reflection, has recently found increasing applicability to the fracture mechanics of engineering materials. Having been widely applied to stress intensity factor measurement, it has found a niche in areas where an analytical prediction has been impossible or in need of experimental verification, such as in dynamic fracture. This paper provides an accessible introduction to the method, covering its historical background and theoretical basis, together with a comprehensive guide to, and review of, its practical application to materials such as aluminium and steel.
Publisher: Elsevier BV
Date: 06-2010
Publisher: Elsevier BV
Date: 09-2008
Publisher: ASME International
Date: 2004
DOI: 10.1115/1.1634278
Abstract: Many analytical and experimental techniques utilize two-dimensional analysis approach to determine residual strains and stresses at cold expanded holes. In the present work, a recently developed technique of hole drilling was used to sketch stress patterns in three-dimension at a particular orientation of split-sleeve cold expanded holes. At this orientation, similarities were obtained in between the present results and the stress distributions measured by Fourier series expansion, neutron diffraction methods and prediction of a recent finite element analysis. It is clear that after cold expansion there are significant variations in residual hoop stresses at different sections through the thickness of the plate. However, finish reaming and de-burring around the hole redistributes residual stresses such that hoop stresses adjacent to the hole along its entire length becomes more compressive and almost uniform. Finally a correlation between stress pattern and crack profile, displaying the through-thickness effect was shown.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 09-2008
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 03-1987
Publisher: Elsevier BV
Date: 03-2020
Publisher: International Union of Crystallography (IUCr)
Date: 08-09-2003
DOI: 10.1107/S0021889803013748
Abstract: The pulsed neutron transmission diffraction technique exploits the sharp steps in intensity (Bragg edges) appearing in the transmitted spectra of thermal neutrons through polycrystalline materials. In this paper the positions of these edges acquired by the time-of-flight (TOF) technique are used to measure accurately the interplanar lattice distances to a resolution of Δ d / d ≃ 10 −4 of specimens subjected to in situ uniaxial tensile loading. The sensitivity of the method is assessed for elastically isotropic (b.c.c. ferritic) and anisotropic (f.c.c. austenitic) polycrystalline specimens of negligible and moderately textured steels. For the more anisotropic austenitic steel, the elastic anisotropy is studied with regard to a Pawley refinement, and compared with previous results from conventional neutron diffraction experiments on the same material. It is shown that the method can be used to determine anisotropic strains, diffraction elastic constants, the residual and applied stress state as well as the unstrained lattice parameter by recording transmission spectra at different specimen inclinations, by complete analogy with the sin 2 ψ technique frequently used in X-ray diffraction. The technique is shown to deliver reliable measures of strain even in the case of moderate texture and elastic anisotropy.
Publisher: Elsevier BV
Date: 1990
Publisher: Springer Science and Business Media LLC
Date: 30-07-2008
Publisher: Springer Science and Business Media LLC
Date: 18-10-2012
Publisher: Crossref
Date: 12-2001
Publisher: Elsevier BV
Date: 06-2014
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 06-1998
Publisher: Elsevier BV
Date: 03-2008
Publisher: Elsevier BV
Date: 03-2012
Publisher: SPIE
Date: 27-02-1997
DOI: 10.1117/12.267881
Publisher: Elsevier BV
Date: 11-1998
Publisher: ASMEDC
Date: 2010
Abstract: A single weld bead deposited on a flat plate is a deceptively simple problem that is in practice a challenge for both measurement and prediction of weld residual stresses. Task Group 1 of the NeT collaborative network has examined this problem in an extensive programme of measurement and simulation extending from 2002 to 2008. As a result, the NeT bead on plate forms an ideal benchmark problem for the development of weld residual stress simulation techniques. One of the conclusions of NeT Task Group 1 is that the most accurate predictions of weld residual stresses in austenitic steels are achieved using mixed isotropic-kinematic material constitutive models. However, the use of these models can require both extensive materials data, and compromises in fitting either the monotonic or cyclic responses. This paper reports a detailed matrix of sensitivity studies aimed at optimising the behaviour of mixed hardening models in welding simulation, using the Lemaitre-Chaboche formulation in the ABAQUS finite element code. Predicted stresses and strains in the NeT bead on plate specimen are compared with the extensive database of residual stress measurements. Further studies examine sensitivity to the handling of high temperature inelastic strains, using a novel two-stage annealing functionality implemented within ABAQUS. The results show that, overall, the most accurate predictions are made if the Lemaitre-Chaboche parameters are optimised to fit the monotonic response over the first 2% of plastic strain. However, further improvements in prediction could be achieved if the constitutive model were capable of independently fitting both the monotonic and saturated cyclic response of the material.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 1997
Publisher: Elsevier BV
Date: 12-2015
Publisher: International Union of Crystallography (IUCr)
Date: 18-07-2002
DOI: 10.1107/S0021889802009044
Abstract: Stress measurement by neutron diffraction depends critically on knowledge of the unstressed lattice parameter ( a 0 ) of the specimen under study. As a result, measurement of stress profiles in components where a 0 is not homogeneous throughout the s le, such as welds or carburized surfaces, can be particularly difficult. An efficient solution to this problem is proposed based on the pulsed neutron transmission diffraction technique. This technique exploits the sharp steps in intensity, the so-called Bragg edges, appearing in the transmitted neutron spectra of polycrystalline materials, such steps being produced by coherent scattering from lattice planes. The position of these Bragg edges as defined by the time-of-flight technique is used to determine precisely local interplanar distances. In this work it is shown that the unstressed lattice parameter of thin specimens subjected to plane stress fields can be defined by recording transmission spectra at different s le inclinations, in complete analogy with the sin 2 ψ technique used in X-ray diffraction. Moreover, by using an array of detectors it is possible to produce a radiographic `image' of a 0 for plane specimens or thin sections out of three-dimensional ones. The capability of the technique is exemplified by mapping the changes in a 0 for a ferritic weld that was used as a round robin s le in an international program for standardization of stress measurements by neutron diffraction.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Crossref
Date: 2004
Publisher: Elsevier BV
Date: 04-2015
Publisher: Elsevier BV
Date: 03-2001
Publisher: Elsevier BV
Date: 10-1993
Publisher: Elsevier BV
Date: 06-1992
Publisher: Crossref
Date: 06-2007
Publisher: Elsevier BV
Date: 08-2014
Publisher: Elsevier BV
Date: 02-2007
Publisher: Elsevier BV
Date: 04-1994
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.1403
Abstract: The current work presents the numerical analysis of solid-state transformation kinetics relating to conventional welding of ferritic steels, with the aim of predicting the constituent phases in both the fusion zone and the heat affected zone (HAZ) of the weldment. The analysis begins with predictions of isothermal transformation kinetics using thermodynamic principles, such that the chemical composition of the parent metal is the sole user-defined input. The data is then converted to anisothermal transformation kinetics using the Scheil-Avrami additive rule, including the effects of peak temperature and austenite grain growth. Subroutines developed for the Abaqus finite element package use the semi-empirical approach described to predict phase transformations in SA508 Gr.3 Cl.1 steel. To study the effect of the cooling rates and the ability of the current model to predict the final microstructure, two weld s les were subjected to autogenous beam TIG welds under a fast (TG5-F, 5.00 mm/s) and slow (TG5-S, 1.25 mm/s) torch speed. Model validation is carried out by direct comparison with microstructural observations and hardness measurements (via nanoindentation) of the fusion and heat affected zones in both welds. Excellent agreement between the measured and predicted hardness has been found for both weld s les. Additionally, it is shown that the correct identification of the partial austenisation region is a crucial input parameter.
Publisher: Elsevier BV
Date: 2011
Publisher: ASMEDC
Date: 2006
DOI: 10.1115/PVP2006-ICPVT-11-93991
Abstract: This paper describes the measurement of longitudinal residual stresses within a specially designed 200×180×25 mm single groove weld specimen. The purpose of these measurements was to quantify the residual stress field arising from a single stringer weld bead laid down within the constraint of a groove in order to validate finite element simulations of the welding process. Measurements were made over the cross section at the mid-bead length, utilising the relatively new Contour method and neutron diffraction. Non destructive neutron diffraction measurements were made using ENGIN-X, the engineering spectrometer at the ISIS facility of the Rutherford Appleton Laboratory (UK). The Contour method measurement was applied destructively at the Open University (UK), producing a detailed full-field residual stress map. Results from these measurements indicate a peak tensile longitudinal residual stress of ∼300 MPa within the parent material adjacent to the weld bead. Good agreement is found between both techniques.
Publisher: Elsevier BV
Date: 05-2012
Publisher: Elsevier BV
Date: 05-2011
Publisher: SAGE Publications
Date: 07-2004
Abstract: In this work, the capability of the synchrotron X-ray diffraction technique to measure changes in the residual strains caused by fatigue crack growth from cold-expanded holes in an aluminium alloy plate has been investigated. The measurement technique was validated by comparing the synchrotron measurements around uncracked holes with those obtained on similar specimens using the neutron diffraction and Sachs' techniques. Measurements were performed with and without superimposed tensile mechanical loading and the results compared with analytical results. The improved spatial resolution of the synchrotron technique relative to the other methods has allowed the strain fields around a fatigue crack growing from a cold-expanded hole to be evaluated in the unloaded state and at two loading levels. Only at the higher load does the crack appear to open along its full length.
Publisher: ASME International
Date: 28-10-2009
DOI: 10.1115/1.4000196
Abstract: Application 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.
Publisher: American Society of Mechanical Engineers
Date: 20-07-2014
Abstract: The current paper presents a finite element analysis of an eight-pass groove weld in a 316L austenitic stainless steel plate. A dedicated welding heat source modelling tool was employed to produce volumetric body power density data for each weld pass, thus simulating weld-induced thermal loads. Thermocouple measurements and cross-weld macrographs taken from a weld specimen were used for heat source calibration. A mechanical finite element analysis was then conducted, using the calibrated thermal loads and a Lemaitre-Chaboche mixed work-hardening model. The predicted post-weld residual stresses were validated using contour method measurements: good agreement between measured and simulated residual stress fields was observed. A sensitivity analysis was also conducted to identify the boundary conditions that best represent a tack-welded I-beam support, which was present on the specimen back-face during the welding.
Publisher: SAGE Publications
Date: 07-2003
DOI: 10.1243/03093240360713478
Abstract: The effect of monotonic compressive loading on the residual stresses developed at cold expanded fastener holes has been investigated using the neutron and X-ray diffraction techniques. Monotonic loading models the effect of the peak of a fatigue loading sequence experienced before a crack is initiated. It was found that the compressive loading significantly affected the residual stress distribution. A low load relaxed only the stresses near to the bore of the hole, whereas a larger load affected the stress distribution over a greater area. Residual stresses measured at the mandrel entrance face were more affected by the compressive loading than the residual stresses measured at the other segments of thickness. The comparison between the X-ray and neutron diffraction results showed that the techniques complemented each other well, enabling a three-dimensional residual stress distribution to be derived. This distribution was used for modelling the effect of compressive loading on fatigue crack growth, using a linear elastic fracture mechanics approach and assuming a stabilized residual stress field.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.777.46
Abstract: Welding processes create a complex transient state of temperature that results in post-weld residual stresses. The current work presents a finite element (FE) analysis of the residual stress distribution in an eight-pass slot weld, conducted using a 316L austenitic stainless steel plate with 308L stainless steel filler metal. A thermal FE model is used to calibrate the transient thermal profile applied during the welding process. Time-resolved body heat flux data from this model is then used in a mechanical FE analysis to predict the resultant post-weld residual stress field. The mechanical analysis made use of the Lemaitre-Chaboche mixed isotropic-kinematic work-hardening model to accurately capture the constitutive response of the 316L weldment during the simulated multi-pass weld process, which results in an applied cyclic thermo-mechanical loading. The analysis is validated by contour method measurements performed on a representative weld specimen. Reasonable agreement between the predicted longitudinal residual stress field and contour measurement is observed, giving confidence in the results of measurements and FE weld model presented.
Publisher: Elsevier BV
Date: 12-2009
Publisher: Elsevier BV
Date: 07-2008
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 07-2008
Publisher: ASMEDC
Date: 2008
Abstract: This work involves the determination of uniaxial stress-strain data from ‘cross-weld’ specimens machined from across a 3 pass welded generic 316 type austenitic stainless steel grooved plate test specimen, using Electronic Speckle Pattern Interferometry (ESPI). ESPI has been applied as a novel surface strain mapping tool for measuring the mechanical properties of uniaxial tensile test specimens with heterogenous microstructures. Using this technique, proof stresses have been measured at different distances from the centre of a manual metal arc (MMA) weld, using a single cross-weld specimen. Mechanical properties were measured using cross-weld specimens taken across a first pass and third pass weld bead, thus allowing the effect of subsequent weld passes on a single weld bead to be quantified. Measurements indicate 0.2% proof stress values more than 100 MPa higher in the first pass weld bead compared to the third pass. This is due to the higher levels of accumulated plastic strain in the first pass weld bead, as a result of thermo-mechanical cycling associated with subsequently deposited weld passes.
Publisher: Springer Science and Business Media LLC
Date: 18-06-2015
Publisher: Elsevier BV
Date: 07-2003
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 10-2014
Publisher: Springer Science and Business Media LLC
Date: 09-2008
DOI: 10.1038/NMAT2266
Publisher: Elsevier BV
Date: 02-1988
Publisher: Elsevier BV
Date: 04-2015
Publisher: Elsevier BV
Date: 07-2014
Publisher: Elsevier BV
Date: 06-2009
Publisher: SAGE Publications
Date: 11-1996
Abstract: Cold expansion of fastener holes is an increasingly common way of improving the fatigue endurance of airframes. Although a number of methods of cold expansion are possible, the split-sleeve cold-expansion process is the most widely accepted and is widely used in the repair and manufacture stages of both military and civil aircraft. In the present work, the residual stress distribution around split-sleeve cold-expanded holes has been measured as a function of both position through the plate thickness and around the hole through novel use of the Sachs method. It is found that the residual hoop stresses being generated at the mid-thickness of the plate at orientation 90° from the position of the split in the expansion sleeve. It is suggested that this variation must be taken into account both in the implementation of the technology and in any potential model used for the prediction of fatigue life of cold-expanded holes.
Publisher: ASMEDC
Date: 2010
Abstract: Residual stresses have been measured by different techniques in a 3-bead slot weld in a carbon steel plate. Neutron diffraction has been applied at two different facilities, the High Flux Reactor of the Joint Research Centre in the Netherlands and the new research reactor FRM-II in Germany. Furthermore, measurements by surface hole drilling and by the contour method have been obtained by the Open University in the UK. The neutron measurements have been executed with different settings of the instruments and employing different crystallographic reflection planes of the bcc-lattice of the low-alloy steel. The results were found to be in remarkably good agreement in the base material, away from the fusion zone. Closer to and within the fusion zone, differences of significant magnitude between the measurements have been found. It has to be noted that the differences found were only in the absolute stress values, and not in the general trends of the stress distributions. The comparison between neutron diffraction and contour data is limited to common measurement locations and directions, e.g. through thickness measurements at the weld centre line and the start and stop ends, in the welding transverse direction, which is the direction of the contour measurements. A reasonable qualitative agreement has been obtained, but no exact quantitative agreement. The paper makes an attempt to explain the similarities and the differences between the measurements, and provides an outlook to additional work done in this context within the NeT European Network, also with a view to establishing methods to obtain better agreement of the stresses found in measurements at different facilities and/or by different methods.
Publisher: Elsevier BV
Date: 11-1994
Publisher: American Society of Mechanical Engineers
Date: 15-07-2012
Abstract: The current paper describes finite element simulation of the complete manufacturing and service exposure history of girth-welded austenitic steel pipes fabricated from ESSHETE 1250 material for the STYLE Framework 7 project. The simulation c aign examines the impacts of prior quenching of pipe material, fabrication of closely adjacent welds, variation in mixed isotropic-kinematic hardening material constitutive models, and high temperature (650°C) service exposure (thermal ageing). The predicted residual stresses are validated using measurements made with the deep hole drilling (DHD) and incremental deep hole drilling (iDHD) techniques.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.652.25
Abstract: The residual strain field around the scratches of 125µm depth and 5µm root radius have been measured from the Synchrotron X-ray diffraction. Scratches were produced using different tools in fine-grained aluminium alloy AA 5091. Residual stresses up to +1700 micro-strains were measured at the scratch tip for one tool but remained up to only +1000 micro-strains for the other tool scratch. The load-displacement curves obtained from nanoindentation were used to determine the residual stresses around the scratches. It was found that the load-displacement curves are sensitive to any local residual stress field present and behave according to the type of residual stresses. This combination of nanoindentation and synchrotron X-rays has been proved highly effective for the study of small-scale residual stresses around the features such as scratches.
Publisher: ASMEDC
Date: 2006
DOI: 10.1115/PVP2006-ICPVT-11-93763
Abstract: Finite element weld residual stress modelling procedures involve complex non-linear analyses where many assumptions and approximations have to be made by the analyst. Weld modelling guidelines for inclusion in the R6 defect assessment procedure are in preparation and will be accompanied by a series of validation benchmarks that can be used to evaluate the accuracy of weld modelling procedures and assess their suitability for use in fracture assessments. It is intended to base one of the benchmarks on a stainless steel bead-on-plate weldment that has been extensively studied by members of Task Group 1 of the NeT European Network project. This paper uses round robin residual stress measurements from the NeT project to derive a statistically based ‘best estimate’ distribution of transverse stress passing through the wall-section at mid-length of the bead-on-plate weldment. The accuracy of a state-of-the-art residual stress prediction is benchmarked against the best estimate measurements using a root mean square error analysis and comparisons of decomposed components of stress. The appropriateness of using the predicted residual stresses in fracture assessments is assessed by comparing stress intensity factors based on the measured and predicted distributions of stress. The results from these studies will be used to help establish accuracy targets and acceptance criteria for the welding benchmark.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Springer Science and Business Media LLC
Date: 12-2002
Publisher: American Society of Mechanical Engineers
Date: 15-07-2012
Abstract: The NeT TG4 benchmark specimen consists of a three pass type 316L TIG slot weld in a AISI type 316L plate. Phase one of the finite element simulation round robin performed on TG4 by the NeT network made the assumption that the weld metal exhibits the same mechanical behaviour as parent material. A comprehensive series of material characterisation tests on weld metal has now been completed, and these have allowed the derivation of a number of mixed isotropic-kinematic material models specifically for weld metal. The derived models have been used to improve the predicted stresses in the TG4 benchmark specimen. This paper first reviews the weld metal materials testing programme, and then discusses the optimum material hardening model fitting strategy to use for austenitic weld metal. The derived material models are tested by using them to predict residual stresses in the TG4 benchmark, and validating the predictions against the extensive database of measured residual stresses, and distortions.
Publisher: American Society of Mechanical Engineers
Date: 15-07-2012
Abstract: Simulation of a dissimilar metal weld (DMW) in a pressurised water reactor (PWR) nozzle was performed to predict both axial distortion and hoop residual stresses in the weld. For this work a computationally efficient axi-symmetric finite element (FE) simulation was carried out rather than a full 3D analysis. Due to the 2-dimensional nature of the analysis it was necessary to examine the effect of structural restraint during welding of the main dissimilar metal weld (DMW). Traditionally this type of analysis is set up to allow one end of the structure, in this case the safe-end forging, to be unrestrained in the axial direction during welding. In reality axial expansion and subsequent contraction of deposited weld metal at the current torch position is restrained by solidified material both ahead and behind the torch. Thus the conventional axi-symmetric analysis is under-restrained in the axial direction at least during the early weld passes. The significance of this was examined by repeating the current simulation with the safe-end forging fixed to limit expansion during the heat up cycle. Contraction was however, allowed during cooling cycle. This modified boundary control method provided a significantly improved prediction of the axial distortion across the weld as well as improved prediction of through wall axial and hoop residual stresses.
Publisher: Wiley
Date: 12-2011
Publisher: Elsevier BV
Date: 05-2006
Publisher: Wiley
Date: 04-1993
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 09-1995
Publisher: Elsevier BV
Date: 04-2005
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 04-2005
Publisher: Wiley
Date: 1995
Publisher: ASMEDC
Date: 2008
Abstract: Knowledge 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.
Publisher: Elsevier BV
Date: 12-2008
Publisher: ASMEDC
Date: 2005
Abstract: This paper describes transverse residual stress and strain measurements aimed at quantifying end effects in single and multi-pass weld-runs. Two test specimens are examined: a 60 mm long weld bead deposited on the surface of a 180 mm × 120 mm × 17 mm thick stainless steel plate, and a 62° arc-length multi-pass repair weld in a 432 mm outer diameter, 19.6 mm thick stainless steel pipe girth weld. The residual stress measurements were made by employing the relatively new Contour method and by neutron diffraction using ENGIN-X, the engineering spectrometer at the ISIS facility of the Rutherford Appleton Laboratory (UK). The measured underlying transverse residual stress levels are observed to be essentially uniform directly beneath the weld bead in the plate specimen and in the heat affected zone beneath the capping passes moving from mid-length towards the stop-end of the pipe repair. However, results from both test components demonstrate the existence of short-range concentrations of transverse residual stress along the welding direction owing to in idual weld capping bead start and stop effects. Such short length-scale stress variations must be allowed for when interpreting residual stress measurements from line-scans. The experimental work also demonstrates the importance of knowing the expected stress or strain distribution prior to choosing measurement lines for detailed study. The Contour measurement method and neutron strain scanning are powerful tools for mapping residual stress and strain fields.
Publisher: Elsevier BV
Date: 05-1996
Publisher: Elsevier BV
Date: 02-2013
Publisher: Informa UK Limited
Date: 04-1986
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 12-1992
Publisher: Elsevier BV
Date: 07-2004
Publisher: Elsevier BV
Date: 1993
Publisher: Elsevier BV
Date: 03-2013
Publisher: Informa UK Limited
Date: 08-1986
Publisher: American Society of Mechanical Engineers
Date: 17-07-2016
Abstract: The residual stress and distortion found in multi-pass welds are often influenced by the prescribed inter-pass temperature. In ferritic steel components, the severity of this influence is affected by solid-state phase transformation (SSPT) kinetics, which will depend on the overall heat input and cooling conditions. The development of an optimised welding procedure to mitigate weld residual stress (WRS) and distortion in these components can therefore necessitate an extensive test matrix, varying both preheat and inter-pass temperatures as well as the transient weld heat input. Computational parametric studies provide an opportunity to dramatically reduce the cost and time associated with the development of welding procedure specifications. Welding procedures can be simulated using validated modelling approaches to examine parametric sensitivity and gain insights into optimal conditions for a given welding task. In the present study, a three-pass tungsten inert gas (TIG) groove weld in SA508 Gr.3 Cl.1 ferritic steel is numerically investigated using the ABAQUS finite element code with a user defined subroutine to incorporate the effect of SSPT kinetics. Parametric sensitivity is assessed whereby a representative heat input is applied to simulate weld deposition for each pass, and the inter-pass temperature is varied to examine its effect on WRS and distortion in the weldment. The implications of the overall heat input on cross-weld microstructure are also presented using this approach.
Publisher: Japan Institute of Metals
Date: 2014
Publisher: Elsevier BV
Date: 02-2004
Publisher: Trans Tech Publications, Ltd.
Date: 08-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.996.512
Abstract: In recent years, considerable progress has been made in the simulation of ferritic steel welding processes. The successful validation of a single-pass autogenous TIG beam weld in SA508 Gr.3 Cl.1 steel has identified key simulation variables required for the accurate prediction of post-weld residual stress in ferritic weldments. The present work outlines a sensitivity study performed to examine the influence of austenite grain growth on predicted solid-state phase transformation kinetics and consequently, residual stress predictions.
Publisher: International Union of Crystallography (IUCr)
Date: 10-11-2006
DOI: 10.1107/S0021889806042245
Abstract: ENGIN-X, a new time-of-flight (TOF) neutron diffractometer optimized to measure elastic strains at precise locations in bulky specimens recently commissioned at the ISIS Facility in the Rutherford Laboratory, UK, is described. Fast counting times, together with a flexible and accurate definition of the instrumental gauge volume are the main requirements of neutron strain scanning and have been addressed on ENGIN-X through the design of a novel TOF diffractometer with a tuneable resolution and interchangeable radial collimators. Further, the routine operation of the instrument has been optimized by creating a virtual instrument, i.e. a three-dimensional computer representation of the diffractometer and s les, which assists in the planning and execution of experiments. On comparing ENGIN-X with its predecessor ENGIN, a 25× gain in performance is found, which has allowed the determination of stresses up to 60 mm deep in steel specimens. For comparison with constant-wavelength diffractometers, special attention has been paid to the absolute number of counts recorded during the experiments. A simple expression is presented for the estimation of counting times in TOF neutron strain scanning experiments.
Publisher: Elsevier BV
Date: 02-1998
Publisher: Elsevier BV
Date: 1994
Publisher: Elsevier BV
Date: 08-1988
Publisher: Elsevier BV
Date: 04-1999
Publisher: Elsevier BV
Date: 05-1996
Publisher: Elsevier BV
Date: 09-2012
Publisher: Crossref
Date: 2004
Publisher: Springer Science and Business Media LLC
Date: 08-1989
DOI: 10.1007/BF02665497
Publisher: Elsevier BV
Date: 2009
Publisher: Informa UK Limited
Date: 04-1996
Publisher: Elsevier BV
Date: 06-1997
Publisher: American Society of Mechanical Engineers
Date: 15-07-2012
Abstract: The implementation of a semi-empirical solid-state phase transformation subroutine in the ABAQUS finite element package is presented to predict the influence of transformation strain on the post-weld residual stress field in ferritic steels. The phase transformation subroutine has been outlined in a previous study (PVP2011-57426), where it was proven accurate in predicting the phase compositions in the fusion and heat affected zone (HAZ) of an autogenous TIG beam weld in SA508 Gr.3 Cl.1 steel. While previous work focused on predictions of the steady-state material response using a 2D thermal model, the present analyses are 3D and capture the varying phase composition at weld start- and stop-ends. Predicted cooling rates at either end of the specimen are significantly higher, leading to a variation in the predicted microstructure along the weld line. To better understand the structural changes that occur in ferritic steels during a conventional welding process, a representative model of SA508 Gr.3 Cl.1 steel is discussed. The contribution of thermal, metallurgical, and transformation-induced plastic strain is highlighted in this ex le, providing insight to the key simulation variables necessary for accurate weld models of ferritic steels. Preliminary coupled thermo-mechanical analyses are presented that compare predicted residual stress distributions with those measured in SA508 Gr.3 Cl.1 beam welds via neutron diffraction good agreement is observed.
Publisher: Elsevier BV
Date: 10-2009
Publisher: International Union of Crystallography (IUCr)
Date: 22-05-2001
DOI: 10.1107/S0021889801003260
Abstract: The positions of Bragg edges in neutron transmission experiments can be defined with high accuracy using the time-of-flight (TOF) technique on pulsed neutron sources. A new dedicated transmission instrument has been developed at ISIS, the UK spallation source, which provides a precision of Δ d / d ≃ 10 −5 in the determination of interplanar distances. This is achieved by fitting a theoretical three-parameter expression to the normalized Bragg edges appearing in the TOF transmission spectra. The technique is demonstrated by experiments performed on iron, niobium and nickel powders. The applicability of using the instrument for the determination of lattice strains in materials has been investigated using a simple in situ loading experiment. Details of the calibration process are presented and the dependence of the resolution and the experimental times required by the transmission geometry on the instrumental variables are studied. Finally, the requirements for a Rietveld-type refinement of transmission data and the advantages and limitations over traditional neutron diffraction peak analysis are discussed.
Publisher: Springer Science and Business Media LLC
Date: 12-1996
DOI: 10.1007/BF00354429
Publisher: Elsevier BV
Date: 10-2004
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 2002
Publisher: Springer Science and Business Media LLC
Date: 02-2009
Publisher: Elsevier BV
Date: 06-2012
Publisher: American Society of Civil Engineers (ASCE)
Date: 07-2004
Publisher: Crossref
Date: 12-2001
Publisher: Crossref
Date: 12-2001
Publisher: Trans Tech Publications, Ltd.
Date: 11-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.772.65
Abstract: Constitutive plasticity theory is commonly applied to the numerical analysis of welds in one of three ways: using an isotropic hardening model, a kinematic hardening model, or a mixed isotropic-kinematic hardening model. The choice of model is not entirely dependent on its numerical accuracy, however, as a lack of empirical data will often necessitate the use of a specific approach. The present paper seeks to identify the accuracy of each formalism through direct comparison of the predicted and actual post-weld residual stress field developed in a three-pass 316LN stainless steel slot weldment. From these comparisons, it is clear that while the isotropic hardening model tends to noticeably over-predict and the kinematic hardening model slightly under-predict the residual post-weld stress field, the results using a mixed hardening model are quantitatively accurate. Even though the kinematic hardening model generally provides more accurate results when compared to an isotropic hardening formalism, the latter might be a more appealing choice to engineers requiring a conservative design regarding weld residual stress.
Publisher: Wiley
Date: 10-1997
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 08-2011
Publisher: Springer Science and Business Media LLC
Date: 12-2016
DOI: 10.1557/ADV.2017.217
Publisher: Elsevier BV
Date: 07-2004
Publisher: Springer Science and Business Media LLC
Date: 12-2002
Publisher: Elsevier BV
Date: 08-2014
Publisher: Trans Tech Publications, Ltd.
Date: 08-2017
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.905.83
Abstract: The need to accurately measure and predict weld residual stresses (WRS) has led to several examinations intent on developing best-practice guidelines in the assessment of welded structures. The present investigation examines two benchmark weld specimens both specimens are autogenous edge-welded beams, with welds deposited using a mechanised tungsten inert gas process. However, one of the beams was made from AISI 316LN austenitic steel, while the other was made from SA508 Gr.3 Cl.1 ferritic steel. Considerable differences in the cross-weld residual stress profile were observed between the two beams, prompting a detailed examination of why such differences exist. Computational weld mechanics was used to assess both processes model validation was achieved using previously reported WRS and micro-hardness measurements. A comparison of the numerical solutions indicates that the shape misfit resulting from a sharp weld-induced thermal gradient causes significant longitudinal tensile stresses in the heat-affected zone in both specimens. The presence of influential solid-state phase transformations in the ferritic specimen leads to the formation of compressive stresses in the weld metal, while the stresses remain tensile in the weld metal region of the austenitic specimen. The compressive stresses in the ferritic specimen serve to offset the tensile stresses in the HAZ, leading to a reduction of the self-equilibrating WRS present in the ferritic parent metal.
Publisher: Elsevier BV
Date: 11-1994
Publisher: Wiley
Date: 21-05-2013
DOI: 10.1111/JACE.12383
Publisher: MDPI AG
Date: 20-01-2023
Abstract: Rich intercultural music engagement (RIME) is an embodied form of engagement whereby in iduals immerse themselves in foreign musical practice, for ex le, by learning a traditional instrument from that culture. The present investigation evaluated whether RIME with Chinese or Middle Eastern music can nurture intercultural understanding. White Australian participants were randomly assigned to one of two plucked-string groups: Chinese pipa (n = 29) or Middle Eastern oud (n = 29). Before and after the RIME intervention, participants completed measures of ethnocultural empathy, tolerance, social connectedness, explicit and implicit attitudes towards ethnocultural groups, and open-ended questions about their experience. Following RIME, White Australian participants reported a significant increase in ethnocultural empathy, tolerance, feelings of social connection, and improved explicit and implicit attitudes towards Chinese and Middle Eastern people. However, these benefits differed between groups. Participants who learned Chinese pipa reported reduced bias and increased social connectedness towards Chinese people, but not towards Middle Eastern people. Conversely, participants who learned Middle Eastern oud reported a significant increase in social connectedness towards Middle Eastern people, but not towards Chinese people. This is the first experimental evidence that participatory RIME is an effective tool for understanding a culture other than one’s own, with the added potential to reduce cultural bias.
Publisher: Elsevier BV
Date: 10-2010
Publisher: Springer Science and Business Media LLC
Date: 02-2006
Publisher: AIP Publishing
Date: 22-03-2005
DOI: 10.1063/1.1861144
Abstract: The total scattering cross section of polycrystalline materials in the thermal neutron region contains valuable information about the scattering processes that neutrons undergo as they pass through the s le. In particular, it displays characteristic discontinuities or Bragg edges of selected families of lattice planes. We have developed a pixelated time-of-flight transmission detector able to record these features and in this paper we examine the potential for quantitative phase analysis and crystalline phase imaging through the examination of a simple two-phase test object. Two strategies for evaluation of the absolute phase volumes (path lengths) are examined. The first approach is based on the evaluation of the Bragg edge litude using basic profile information. The second approach focuses on the information content of certain regions of the spectrum using a Rietveld-type fit after first identifying the phases via the characteristic edges. The phase distribution is determined and the coarse chemical species radiographic image reconstructed. The accuracy of this method is assessed.
Publisher: ASMEDC
Date: 2010
Abstract: A single weld bead deposited on a flat plate is a deceptively simple problem that is, in practice, a significant challenge for both measurement and prediction of weld residual stresses. Task Group 1 of the NeT collaborative network has examined this problem in an extensive programme of measurement and simulation extending from 2002 to 2008. Thus, the NeT bead on plate forms an ideal benchmark problem for the development of weld residual stress simulation techniques. It is often difficult to separate the influence of different analysis variables in a large collaborative study such as NeT Task Group 1. This paper examines sensitivity to mesh design, element type, and heat source characteristics in a closely controlled study using several different mesh designs, element types (both tetrahedral and hexahedral), and heat sources, but the same material constitutive model and finite element analysis code. It complements a companion paper that varies material constitutive models. A dedicated heat source modelling tool with a semi-automatic interface to the ABAQUS finite element code has been used to vary the heat source characteristics, thus facilitating rapid and controlled sensitivity studies without the need for bespoke heat source coding within ABAQUS.
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 07-2015
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 11-2015
Publisher: Wiley
Date: 05-2005
Publisher: Springer Science and Business Media LLC
Date: 11-04-2014
Publisher: Crossref
Date: 12-2003
Publisher: Informa UK Limited
Date: 1987
Publisher: Springer Science and Business Media LLC
Date: 12-2002
Publisher: ASMEDC
Date: 2011
Abstract: The numerical application of solid-state phase transformation kinetics relating to conventional welding of ferritic steels is presented. The inclusion of such kinetics in weld models is shown to be necessary for capturing the post-weld residual stress field. To this end, a comparison of two approaches is outlined: a semi-empirical approach that uses thermodynamic transformation kinetics to predict phase morphology and a fully empirical approach that directly links local material temperature to the present constituent phase(s). The semi-empirical analysis begins with prediction of TTT diagrams using thermodynamic principles for ferritic steels. The data is then converted to CCT diagrams using the Scheil-Avrami additive rule, including austenite grain growth kinetics. This information is used to predict the phases present under varying peak temperatures and cooling rates. In the fully empirical approach, dilatometric experiments of steel s les are performed during heating to simulate expected welding conditions. The constitutive response of the s le is then used as input for the subsequent numerical weld analyses. Input derived from each technique is transferred into weld models developed using the Abaqus finite element package. Model validation is carried out by direct comparison with neutron diffraction residual stress measurements on two beams of SA508 Gr.3 Cl.1 steel subjected to autogenous beam TIG welds under varying torch speeds, heat input and preheat conditions.
Publisher: Oxford University Press (OUP)
Date: 25-06-2014
DOI: 10.1017/S1431927614001640
Abstract: This paper reports a study of local orientation change occurring within micro-scale tensile s les as a function of strain. These s les were fabricated from a thin film of single crystal bcc Fe and deformed in tension using an in situ micro-mechanical testing device inside a scanning electron microscope. S les were loaded along the direction parallel to the specimen axis, strained to different levels, and then subjected to electron backscatter diffraction scans over the entire area of the gauge section. Analysis of the surface orientation data shows that, within a necked zone of the micro-s le gauge section, there are two distinct regions of significant orientation change, in which local crystal rotations occur in opposite directions. These two regions are separated by an intermediate band that shows minimal misorientation from the original state. Crystal rotations within the two regions that develop opposite orientations are found to be consistent with classic single crystal slip, where the slip direction rotates toward the tensile axis. It is shown that increasing tensile strain causes an increasing degree of rotation away from the starting orientation. The tests also illustrate the occurrence of slip on at least two different slip systems, based on the slip traces and orientation change.
Publisher: Informa UK Limited
Date: 1987
Publisher: ASME International
Date: 09-01-2007
DOI: 10.1115/1.2647503
Abstract: The impact and fatigue resistance of overlay coatings is significantly influenced by the residual strain (or stress) field induced during coating deposition, post-treatment, and in-service loading. Optimization of the residual strain field is therefore critical to the life and performance of components. Nondestructive measurement of these strain fields in relatively thin (300-400μm) thermal spray coatings, however, poses a challenge because conventional techniques, such as deep hole drilling, x-ray diffraction, synchrotron diffraction, and changes in beam curvature either make these techniques destructive and/or provides only a very near-surface strain measurement. This particularly complicates the strain analysis in cermet coatings, e.g., WC-Co deposited by the thermal spraying process, where the low penetration depth of x-ray and synchrotron-diffraction ray can only provide a through thickness measurement of stress or strain profile via the destructive layer removal technique. Recent investigations have therefore concentrated on the use of neutron diffraction technique for such analysis, and this paper reports some of the early findings of the comparison of through thickness strain measurements in relatively thin (400μm) as-sprayed and post-treated WC-12wt.%Co coatings via the neutron diffraction technique. Since neutrons are not charged, they do not interact with the electron cloud surrounding the atom (unlike x-ray) hence, diffraction results from the interaction with the atomic nucleus. Neutrons therefore have greater penetration depth in most engineering materials, and therefore provide a nondestructive through thickness strain measurement. Results of strain measurement are discussed with the structure property relationships and contact fatigue performance, and indicate that post-treatment of these coatings results in harmonization of the strain field within the coating, and at the coating substrate interface. This significantly influences the contact fatigue performance by improving both the cohesive and adhesive strength of these coatings.
Publisher: Maney Publishing
Date: 11-2013
Publisher: Elsevier BV
Date: 02-2006
Publisher: Elsevier BV
Date: 08-2017
Publisher: Wiley
Date: 06-2001
DOI: 10.1002/1521-396X(200106)185:2<221::AID-PSSA221>3.0.CO;2-C
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: Australia
Start Date: 2009
End Date: 12-2010
Amount: $1,000,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2009
End Date: 12-2010
Amount: $575,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2015
End Date: 02-2021
Amount: $4,000,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2023
End Date: 12-2025
Amount: $664,806.00
Funder: Australian Research Council
View Funded Activity