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Nobuhisa Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Crack geometry effect on stress strain fields for Crack under biaxial loading
Journal of Pressure Vessel Technology-transactions of The Asme, 2010Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near-Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near-Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.
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Crack geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
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Crack geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
Fumiyoshi Minami - One of the best experts on this subject based on the ideXlab platform.
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Fracture Assessment of Weld Joints of High-Strength Steel in Pre-Strained Condition
MDPI AG, 2019Co-Authors: Jeongung Park, Mituru Ohata, Fumiyoshi MinamiAbstract:Unstable fractures tend to occur after ductile Crack initiation or propagation. In most collapsed steel structures, a maximum 15% pre-strain was recorded, at the steel structural connections, during the great earthquake of 1995, in Japan. Almost-unstable fractures were observed in the beam-to-column connections, where geometrical discontinuities existed. Structural collapse and unstable failure occurred after large-scale plastic deformations. Ship structures can also suffer from unstable fractures in the welded joints. The fracture resistance of butt-welded joints subjected to tension in the pre-strained condition was estimated by considering the toughness deterioration, due to pre-strain and toughness correction for constraint loss in a tension specimen. The target specimen for this fracture assessment was a double-edged, through-Thickness Crack panel, with a Crack in the weld joint (heat-affected zone (HAZ)). The critical fracture toughness value (Crack tip opening displacement (CTOD)) of a large structure with pre-strain, which was applied to the HAZ region, was estimated from a small-scale, pre-stained, three-point bend specimen. Fracture toughness values, evaluated by a CTOD test, were recently mandated for shipbuilding steel plates. The critical fracture toughness value is a very useful parameter to evaluate the safety of huge ship structures
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Crack geometry effect on stress strain fields for Crack under biaxial loading
Journal of Pressure Vessel Technology-transactions of The Asme, 2010Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near-Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near-Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.
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Crack geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
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Crack geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Daisuke Watanabe, Takahiro Kubo, Mitsuru Ohata, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-Thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-Thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
Tongjie Wang - One of the best experts on this subject based on the ideXlab platform.
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the effect of out of plane constraint on the stress fields near the front of a Crack in a thin ductile plate
International Journal of Solids and Structures, 2020Co-Authors: Tongjie WangAbstract:Abstract Classical plane solutions based on the elastic-plastic fracture mechanics are applied widely in practical engineering. These plane solutions follow the plane stress or plane strain assumption. However, in the case of a thin ductile plate with a through-Thickness Crack under tension, plane stress conditions exist at a distance of about one half of the plate Thickness ahead of the Crack front cross the Thickness of the plate. What is the stress state in the region where both plane strain and plane stress conditions cannot be met? In the current paper, a semi-analytical method is presented to investigate the problem. Three dimensional Maxwell stress functions, the minimum complementary potential energy principle and three dimensional J-integrals are employed to obtain solutions for Crack front fields in a thin ductile plate. Three-dimensional finite element (FE) analyses are carried out to verify the current solutions. FE results reveal that the out-of-plane constraint level Tz increases with increasing remote loading near the Crack front. FE results also show that the in-plane stress fields near the Crack front can be characterized by the current J-Tz solutions. Both FE and theoretical results illustrate that opening stresses decrease gradually to the corresponding plane stress HRR-field solutions with increasing radial distance r from the Crack front in the mid-plane when remote loading is large enough.
D L Chen - One of the best experts on this subject based on the ideXlab platform.
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effect of welding energy on microstructure and strength of ultrasonic spot welded dissimilar joints of aluminum to steel sheets
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016Co-Authors: F A Mirza, S D Bhole, D L Chen, A Macwan, X G ChenAbstract:Abstract Two dissimilar ultrasonic spot welded joints of aluminum to commercial steel sheets at different levels of welding energy were investigated. The tensile lap shear tests were conducted to evaluate the failure strength in relation to microstructural changes. The main intermetallics at the weld interface in both joints was θ (FeAl 3 ), along with ɳ (Fe 2 Al 5 ) phase in Al-to-AISI 304 stainless steel joint and Fe 3 Al phase in Al-to-ASTM A36 steel joint, respectively. The welding strength of Al-to-AISI 304 stainless steel weld samples was slightly higher than Al-to-ASTM A36 steel weld samples, whereas the fracture energies of Al-to-AISI 304 stainless steel weld samples were significantly higher as compared with Al-to-ASTM A36 steel weld samples. The welding strength of both Al-to-Steel welds were higher than other reported dissimilar USW joints in literature. The fracture surfaces of both weld joints exhibits the growth of IMC layer with increasing welding energy or time, whose inherent brittleness compromises the integrity of joints. In both cases, the lap shear tensile fracture occurred from the Al/Fe interface at lower energy inputs and the failure mode at higher welding energy inputs became the “transverse through-Thickness Crack growth” at the edge of the nugget zone on the softer Al side.
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ultrasonic spot welding of aluminum to high strength low alloy steel microstructure tensile and fatigue properties
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2014Co-Authors: V K Patel, S D Bhole, D L ChenAbstract:The structural applications of lightweight aluminum alloys inevitably involve dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change, lap shear tensile load, and fatigue resistance of dissimilar ultrasonic spot-welded joints of aluminum-to-galvanized high-strength low-alloy (HSLA) steel. Two non-uniform layers were identified in between Al and HSLA steel via SEM/EDS and XRD. One was an Al-Zn eutectic layer and the other was a thin (<2 μm) layer of intermetallic compound (IMC) of Al and Fe in the nugget zone. The lap shear tensile testing gave a maximum load of 3.7 kN and the sample failed initially in between the Al-Zn eutectic film and Al-Fe IMC, and afterward from the region containing Al on both matching fracture surfaces. The fatigue test results showed a fatigue limit of about 0.5 kN (at 1 × 107 cycles). The maximum cyclic stress at which transition of the fatigue fracture from transverse through-Thickness Crack growth mode to the interfacial failure mode occurs increases with increasing energy input.
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ultrasonic spot welding of aluminum to high strength low alloy steel microstructure tensile and fatigue properties
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2014Co-Authors: V K Patel, S D Bhole, D L ChenAbstract:The structural applications of lightweight aluminum alloys inevitably involve dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change, lap shear tensile load, and fatigue resistance of dissimilar ultrasonic spot-welded joints of aluminum-to-galvanized high-strength low-alloy (HSLA) steel. Two non-uniform layers were identified in between Al and HSLA steel via SEM/EDS and XRD. One was an Al-Zn eutectic layer and the other was a thin (<2 μm) layer of intermetallic compound (IMC) of Al and Fe in the nugget zone. The lap shear tensile testing gave a maximum load of 3.7 kN and the sample failed initially in between the Al-Zn eutectic film and Al-Fe IMC, and afterward from the region containing Al on both matching fracture surfaces. The fatigue test results showed a fatigue limit of about 0.5 kN (at 1 × 107 cycles). The maximum cyclic stress at which transition of the fatigue fracture from transverse through-Thickness Crack growth mode to the interfacial failure mode occurs increases with increasing energy input.
Reaz A. Chaudhuri - One of the best experts on this subject based on the ideXlab platform.
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three dimensional mixed mode i ii iii singular stress field at the front of a varvec mathbf 111 varvec bar mathbf 1 bar mathbf 1 mathbf 2 varvec times mathbf 1 bar mathbf 1 mathbf 0 varvec Crack weakening a diamond cubic mono crystalline plate with c
International Journal of Fracture, 2014Co-Authors: Reaz A. ChaudhuriAbstract:A heretofore-unavailable mixed Frobenius type series, in terms of affine-transformed x-y coordinate variables of the Eshelby–Stroh type, is introduced to develop a new eigenfunction expansion technique. This is used, in conjunction with separation of the z-variable, to derive three-dimensional mixed-mode I+II+III asymptotic displacement and stress fields in the vicinity of the front of a semi-infinite through-Thickness \((111)[\bar{{1}}\bar{{1}}2]\times [1\bar{{1}}0]\) Crack weakening an infinite diamond cubic mono-crystalline plate. Crack-face boundary conditions and those that are prescribed on the top and bottom (free, fixed or lubricated) surfaces of the diamond cubic mono-crystalline plate are exactly satisfied. Explicit expressions for the mixed mode I+II+III singular stresses in the vicinity of the front of the through-Thickness Crack, are presented. Most important mixed modes I+II+III response is elicited even though the far-field loading is only mode I or II or III or any combination thereof. Finally, atomistic modeling of Cracks requires consideration of both the long range elastic interactions and the short range physico-chemical reactions, such as bond breaking. The Griffith-Irwin approach does not take the latter into account, and nano-structural details such as bond orientation must be accounted for. A new mixed-mode I+II+III Crack deflection criterion elucidates the formation of steps and/or triangular ridges on the Crack path. The planes of a multiply deflected Crack are normal to the directions of broken bonds. Additionally, the mixed-mode (I+II+III) Crack deflection and ridge formation are found to be strongly correlated with the elastic stiffness constants, \({c}^{\prime }_{14}\) and \({c}^{\prime }_{56}\), of the diamond cubic single crystal concerned.
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three dimensional singular stress field at the front of a Crack weakening a unidirectional fiber reinforced composite plate
Composite Structures, 2011Co-Authors: Reaz A. ChaudhuriAbstract:Abstract An eigenfunction expansion technique, based in part on separation of the Thickness-variable and partly on the Eshelby–Stroh type affine transformation, is employed to derive hitherto unavailable three-dimensional asymptotic stress field in the vicinity of the front of a semi-infinite through-Thickness Crack weakening an infinite transversely isotropic unidirectional fiber reinforced composite plate, of finite Thickness and subjected to far-field mode I/II loadings. Crack-face boundary conditions and those that are prescribed on the top and bottom (free, fixed or lubricated) surfaces of the lamina are exactly satisfied. The present investigation considers mainly two through-Crack systems – (i) (0 1 0)[0 0 1] with the [1 0 0] propagation direction, and (ii) ( 1 ¯ 0 0 ) [ 0 0 1 ] with the [0 1 0] propagation direction. Explicit expressions for the singular stresses in the vicinity of the front of a through-Thickness Crack weakening a transversely isotropic unidirectional fiber reinforced composite plate, subjected to far-field mode I/II loadings, are presented. Hitherto unavailable numerical results, pertaining to the through-Thickness variations of stress intensity factors for saw-tooth load and its skew-symmetric counterpart that also satisfy the boundary conditions on the top and bottom surfaces of the Cracked unidirectional fiber reinforced composite (transversely isotropic) plates under investigation, bridge a longstanding gap in the fracture mechanics literature.
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on three dimensional singular stress residual stress fields at the front of a Crack antiCrack in an orthotropic orthorhombic plate under anti plane shear loading
Composite Structures, 2010Co-Authors: Reaz A. ChaudhuriAbstract:Abstract A novel eigenfunction expansion technique, based in part on separation of the Thickness-variable, is developed to derive three-dimensional asymptotic stress field in the vicinity of the front of a semi-infinite through-Thickness Crack/antiCrack weakening/reinforcing an infinite orthotropic/orthorhombic plate, of finite Thickness and subjected to far-field anti-plane shear loading. Crack/antiCrack-face boundary conditions and those that are prescribed on the top and bottom (free, fixed and lubricated) surfaces of the orthotropic plate are exactly satisfied. Five different through-Thickness Crack/antiCrack-face boundary conditions are considered: (i) slit Crack, (ii) antiCrack or perfectly bonded rigid inclusion, (iii) transversely rigid inclusion (longitudinal slip permitted), (iv) rigid inclusion in part perfectly bonded, the remainder with slip, and (v) rigid inclusion located alongside a Crack. Explicit expressions for the singular stress fields in the vicinity of the fronts of the through-Thickness Cracks, antiCracks or mixed Crack–antiCrack type discontinuities, weakening/reinforcing orthotropic/orthorhombic plates, subjected to far-field anti-plane shear (mode III) loadings, are presented. In addition, singular residual stress fields in the vicinity of the fronts of these Cracks, antiCracks and similar discontinuities are also discussed.
