The Experts below are selected from a list of 11025 Experts worldwide ranked by ideXlab platform
Denis Thibault - One of the best experts on this subject based on the ideXlab platform.
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residual stress characterization in low transformation temperature 13 cr 4 ni stainless steel weld by neutron diffraction and the contour method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Denis Thibault, Philippe Bocher, Marc Thomas, Michael A Gharghouri, Marjolaine CoteAbstract:Abstract This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr–4%Ni welds made using 410NiMo weld filler metal. The transverse, Longitudinal and normal components of stress were determined by neutron diffraction. The Longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of Longitudinal Tension. These results are explained with reference to the low martensitic transformation start temperature (Ms) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136 MPa, and the maximum compressive stress was reduced from 371 to 152 MPa.
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residual stress and microstructure in welds of 13 cr 4 ni martensitic stainless steel
Journal of Materials Processing Technology, 2009Co-Authors: Denis Thibault, Philippe Bocher, Marc ThomasAbstract:Abstract The objectives of the present study were to characterize the distribution of residual stress and the microstructure changes induced by welding in the heat-affected zone (HAZ) of 13%Cr–4%Ni used in hydraulic turbine fabrication to deduce best practices. To characterize residual stress after welding, hole-drilling, X-ray diffraction (XRD) and the contour method were used on a FCAW 6 passes UNS W41036 (410NiMo) weld deposited on UNS S41500 (13%Cr–4%Ni) stainless steel; the results were put side to side with the weld microstructure and hardness to assess their criticality. Transverse compression was found in and around the last bead of the weld by XRD and hole-drilling. Longitudinal compression stress was found in and around the last bead while Longitudinal Tension was found near the low-temperature HAZ. The contour method showed that despite high compression in the last bead, high Longitudinal Tension exists in the rest of the weld and just below the weld. The superposition of both residual stress distribution and results from microstructural characterization shows that in multipass welding of 13%Cr–4%Ni martensitic stainless steel, cracking susceptibility is higher in the weld than in the HAZ, let it be fatigue cracking, environment-assisted cracking or cold cracking during welding. Post-weld heat treatment proved to be very efficient in lowering residual Tension found in the first bead and in lowering the hardness of the weld. These results underline the importance of following proper procedures when welding these steels; this being even more true when the assembly is loaded in fatigue.
Soraia Pimenta - One of the best experts on this subject based on the ideXlab platform.
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Microscale material variability and its effect on Longitudinal tensile failure of unidirectional carbon fibre composites
Composite Structures, 2020Co-Authors: Fabio Malgioglio, Stepan Vladimirovitch Lomov, Soraia Pimenta, Anna Matveeva, Laszlo Farkas, Wim Desmet, Yentl SwolfsAbstract:Abstract This paper deals with modelling the effect of local fibre volume fraction variability, fibre misalignment and fibre strength variability on the Longitudinal tensile strength of unidirectional plies with finite element analysis. Variability is accounted for by generating spatially-correlated fields of fibre misalignment and volume fraction. This information is then translated into local mechanical properties and orientations in finite element models of the ply, which are virtually tested in Longitudinal Tension. Monte Carlo simulations were performed to evaluate the effect of different sources of material variability, i.e. local fibre strength, fibre volume fraction and misalignment. Ply strength predictions lowered when including the variability of local volume fraction and fibre misalignment in the modelling, showing a better agreement with experiments for the carbon/epoxy system investigated.
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a computationally efficient micromechanical model for the fatigue life of unidirectional composites under Tension Tension loading
International Journal of Fatigue, 2018Co-Authors: Marco Alves, Soraia PimentaAbstract:Abstract Failure of fibre-reinforced composites is affected by fatigue, which increases the challenge in designing safe and reliable composite structures. This paper presents an analytical model to predict the fatigue life of unidirectional composites under Longitudinal Tension-Tension. The matrix and fibre-matrix interface are represented through a cohesive constitutive law, and a Paris law is used to model fatigue due to interfacial cracks propagating from fibre-breaks. The strength of single-fibres is modelled by a Weibull distribution, which is scaled hierarchically though a stochastic failure analysis of composite fibre-bundles, computing stochastic S-N curves of lab-scaled specimens in less than one minute. Model predictions are successfully validated against experiments from the literature. This model can be used to reduce the need for fatigue testing, and also to evaluate the impact of constituent properties on the fatigue life of composites.
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Benchmarking of strength models for unidirectional composites under Longitudinal Tension
Composites Part A: Applied Science and Manufacturing, 2018Co-Authors: Larissa Gorbatikh, Ian Sinclair, Soraia Pimenta, Hannah Morton, Mark Spearing, Yentl SwolfsAbstract:Several modelling approaches are available in the literature to predict Longitudinal tensile failure of fibre-reinforced polymers. However, a systematic, blind and unbiased comparison between the predictions from the different models and against experimental data has never been performed. This paper presents a benchmarking exercise performed for three different models from the literature: (i) an analytical hierarchical scaling law for composite fibre bundles, (ii) direct numerical simulations of composite fibre bundles, and (iii) a multiscale finite-element simulation method. The results show that there are significant discrepancies between the predictions of the different modelling approaches for fibre-break density evolution, cluster formation and ultimate strength, and that each of the three models presents unique advantages over the others. Blind model predictions are also compared against detailed computed-tomography experiments, showing that our understanding of the micromechanics of Longitudinal tensile failure of composites needs to be developed further.
Marc Thomas - One of the best experts on this subject based on the ideXlab platform.
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residual stress characterization in low transformation temperature 13 cr 4 ni stainless steel weld by neutron diffraction and the contour method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Denis Thibault, Philippe Bocher, Marc Thomas, Michael A Gharghouri, Marjolaine CoteAbstract:Abstract This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr–4%Ni welds made using 410NiMo weld filler metal. The transverse, Longitudinal and normal components of stress were determined by neutron diffraction. The Longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of Longitudinal Tension. These results are explained with reference to the low martensitic transformation start temperature (Ms) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136 MPa, and the maximum compressive stress was reduced from 371 to 152 MPa.
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residual stress and microstructure in welds of 13 cr 4 ni martensitic stainless steel
Journal of Materials Processing Technology, 2009Co-Authors: Denis Thibault, Philippe Bocher, Marc ThomasAbstract:Abstract The objectives of the present study were to characterize the distribution of residual stress and the microstructure changes induced by welding in the heat-affected zone (HAZ) of 13%Cr–4%Ni used in hydraulic turbine fabrication to deduce best practices. To characterize residual stress after welding, hole-drilling, X-ray diffraction (XRD) and the contour method were used on a FCAW 6 passes UNS W41036 (410NiMo) weld deposited on UNS S41500 (13%Cr–4%Ni) stainless steel; the results were put side to side with the weld microstructure and hardness to assess their criticality. Transverse compression was found in and around the last bead of the weld by XRD and hole-drilling. Longitudinal compression stress was found in and around the last bead while Longitudinal Tension was found near the low-temperature HAZ. The contour method showed that despite high compression in the last bead, high Longitudinal Tension exists in the rest of the weld and just below the weld. The superposition of both residual stress distribution and results from microstructural characterization shows that in multipass welding of 13%Cr–4%Ni martensitic stainless steel, cracking susceptibility is higher in the weld than in the HAZ, let it be fatigue cracking, environment-assisted cracking or cold cracking during welding. Post-weld heat treatment proved to be very efficient in lowering residual Tension found in the first bead and in lowering the hardness of the weld. These results underline the importance of following proper procedures when welding these steels; this being even more true when the assembly is loaded in fatigue.
Yentl Swolfs - One of the best experts on this subject based on the ideXlab platform.
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Microscale material variability and its effect on Longitudinal tensile failure of unidirectional carbon fibre composites
Composite Structures, 2020Co-Authors: Fabio Malgioglio, Stepan Vladimirovitch Lomov, Soraia Pimenta, Anna Matveeva, Laszlo Farkas, Wim Desmet, Yentl SwolfsAbstract:Abstract This paper deals with modelling the effect of local fibre volume fraction variability, fibre misalignment and fibre strength variability on the Longitudinal tensile strength of unidirectional plies with finite element analysis. Variability is accounted for by generating spatially-correlated fields of fibre misalignment and volume fraction. This information is then translated into local mechanical properties and orientations in finite element models of the ply, which are virtually tested in Longitudinal Tension. Monte Carlo simulations were performed to evaluate the effect of different sources of material variability, i.e. local fibre strength, fibre volume fraction and misalignment. Ply strength predictions lowered when including the variability of local volume fraction and fibre misalignment in the modelling, showing a better agreement with experiments for the carbon/epoxy system investigated.
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Benchmarking of strength models for unidirectional composites under Longitudinal Tension
Composites Part A: Applied Science and Manufacturing, 2018Co-Authors: Larissa Gorbatikh, Ian Sinclair, Soraia Pimenta, Hannah Morton, Mark Spearing, Yentl SwolfsAbstract:Several modelling approaches are available in the literature to predict Longitudinal tensile failure of fibre-reinforced polymers. However, a systematic, blind and unbiased comparison between the predictions from the different models and against experimental data has never been performed. This paper presents a benchmarking exercise performed for three different models from the literature: (i) an analytical hierarchical scaling law for composite fibre bundles, (ii) direct numerical simulations of composite fibre bundles, and (iii) a multiscale finite-element simulation method. The results show that there are significant discrepancies between the predictions of the different modelling approaches for fibre-break density evolution, cluster formation and ultimate strength, and that each of the three models presents unique advantages over the others. Blind model predictions are also compared against detailed computed-tomography experiments, showing that our understanding of the micromechanics of Longitudinal tensile failure of composites needs to be developed further.
Philippe Bocher - One of the best experts on this subject based on the ideXlab platform.
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residual stress characterization in low transformation temperature 13 cr 4 ni stainless steel weld by neutron diffraction and the contour method
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Denis Thibault, Philippe Bocher, Marc Thomas, Michael A Gharghouri, Marjolaine CoteAbstract:Abstract This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr–4%Ni welds made using 410NiMo weld filler metal. The transverse, Longitudinal and normal components of stress were determined by neutron diffraction. The Longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of Longitudinal Tension. These results are explained with reference to the low martensitic transformation start temperature (Ms) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136 MPa, and the maximum compressive stress was reduced from 371 to 152 MPa.
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residual stress and microstructure in welds of 13 cr 4 ni martensitic stainless steel
Journal of Materials Processing Technology, 2009Co-Authors: Denis Thibault, Philippe Bocher, Marc ThomasAbstract:Abstract The objectives of the present study were to characterize the distribution of residual stress and the microstructure changes induced by welding in the heat-affected zone (HAZ) of 13%Cr–4%Ni used in hydraulic turbine fabrication to deduce best practices. To characterize residual stress after welding, hole-drilling, X-ray diffraction (XRD) and the contour method were used on a FCAW 6 passes UNS W41036 (410NiMo) weld deposited on UNS S41500 (13%Cr–4%Ni) stainless steel; the results were put side to side with the weld microstructure and hardness to assess their criticality. Transverse compression was found in and around the last bead of the weld by XRD and hole-drilling. Longitudinal compression stress was found in and around the last bead while Longitudinal Tension was found near the low-temperature HAZ. The contour method showed that despite high compression in the last bead, high Longitudinal Tension exists in the rest of the weld and just below the weld. The superposition of both residual stress distribution and results from microstructural characterization shows that in multipass welding of 13%Cr–4%Ni martensitic stainless steel, cracking susceptibility is higher in the weld than in the HAZ, let it be fatigue cracking, environment-assisted cracking or cold cracking during welding. Post-weld heat treatment proved to be very efficient in lowering residual Tension found in the first bead and in lowering the hardness of the weld. These results underline the importance of following proper procedures when welding these steels; this being even more true when the assembly is loaded in fatigue.
