Browsing by Author "Turski, M"

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    Full 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, PJ
    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. © 2008 ASME
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    Neutron diffraction residual stress measurements in a 316L stainless steel bead-on-plate weld specimen.
    (Elsevier, 2009-01) Pratihar, S; Turski, M; Edwards, L; Bouchard, PJ
    The 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.
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    Residual stress measurement of a 316l stainless steel bead-on-plate specimen utilising the contour method
    (Elsevier, 2009-01) Turski, M; Edwards, L
    This paper describes the mapping of transverse residual stresses within a single bead-on-plate round robin test specimen. The purpose of these measurements was to quantify the magnitude and shape of the residual stress field arising from a single weld bead laid down on an austenitic stainless steel plate. Measurements were made through the thickness of the specimen using the contour method. The contour method is a new destructive, stress relaxation method allowing the full field residual stress to be measured. Results from these measurements show transverse tensile residual stresses over 150 MPa below the plate surface along the length of the weld bead with peak stresses of up to 210 MPa close to the weld stop position. Finally, as these measurements are insensitive to local microstructure variations within the specimen (i.e. texture or variations in lattice parameter), they are useful in helping to validate diffraction based residual stress measurements made within this round robin measurement program. © 2009, Elsevier Ltd.
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    Spatially 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, PJ
    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. © 2009, American Society of Mechanical Engineers (ASME)
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    Validation of predicted residual stresses within direct chill cast magnesium alloy slab
    (Springer, 2012-05-01) Turski, M; Paradowska, AM; Zhang, SY; Mortensen, D; Fjaer, H; Grandfield, J; Davis, B; DeLorme, R
    A significant level of cold cracking has been observed within direct chill (DC) cast, high-strength magnesium alloy Elektron WE43. These cracks have been attributed to the formation of significant residual stresses during casting. A finite-element modeling (FEM) code, which is called ALSIM, has been used to predict the residual stress within the DC-cast slab. Verification of the predicted residual stress field within an 870 × 315-mm sized slab has been carried out using neutron diffraction measurements. Given that measurements in such large-scale components using diffraction measurements are particularly challenging and expensive, the efficient use of neutron diffraction measurements is emphasized. This has included the use of sectioning, allowing the residual stress within the slab to be mapped in detail. © 2012, Springer.