The Experts below are selected from a list of 4527 Experts worldwide ranked by ideXlab platform
S Mall - One of the best experts on this subject based on the ideXlab platform.
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corrosion fatigue crack growth behavior of 7075 t6 under biaxial tension tension Cyclic Loading Condition
Engineering Fracture Mechanics, 2013Co-Authors: Heath Edward Misak, V. Sabelkin, V Y Perel, S MallAbstract:Abstract Biaxial and uniaxial fatigue crack growth of aluminum alloy 7075-T6 was characterized under air and salt water (3.5%) environments. Biaxial fatigue increased crack growth rate in region I relative to uniaxial fatigue under both environments. Biaxial fatigue increased crack growth rate in region II relative to uniaxial fatigue under salt environment. Crack growth rates in region I were comparable in air and salt environments, while they were faster in salt water than air environment in region II. Biaxial fatigue in salt environment exhibited intergranular cracks along with main transgranular fracture. A mechanism for biaxial corrosion fatigue crack growth is proposed.
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Cyclic and sustained Loading behaviors of oxide oxide nextel 720 alumina composite with double edge sharp notch
Composites Part A-applied Science and Manufacturing, 2012Co-Authors: S Mall, B H BoyerAbstract:Abstract This study investigated an oxide/oxide CMC consisting of Nextel™720 (meta-stable mullite) fibers in alumina matrix, N720/A, with 0°/90° fiber orientation having double edge sharp notch under sustained and Cyclic Loading Conditions at 1200 °C in laboratory air environment. Monotonic tensile tests at 1200 °C were also conducted. Fracture surfaces were examined to analyze failure and damage mechanisms. Comparisons with counterparts from unnotched geometry showed N720/A is mildly sensitive to the sharp notch under monotonic tensile, creep and fatigue Loading Conditions. The ultimate tensile strength of the composite was reduced by about 15% in the presence of the sharp notch. The rupture strength of the sharp notched geometry was reduced by about 15% of unnotched geometry for a given rupture time. The fatigue strength was reduced by about 20% of unnotched geometry for a given number of cycles to failure. Deformation under Cyclic Loading Condition had contributions both from fatigue and creep. Damage mechanisms were identical under Cyclic and sustained Loading Conditions.
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Cyclic and sustained Loading behaviors of oxide/oxide Nextel™720/alumina composite with double edge sharp notch
Composites Part A: Applied Science and Manufacturing, 2012Co-Authors: S Mall, B H BoyerAbstract:Abstract This study investigated an oxide/oxide CMC consisting of Nextel™720 (meta-stable mullite) fibers in alumina matrix, N720/A, with 0°/90° fiber orientation having double edge sharp notch under sustained and Cyclic Loading Conditions at 1200 °C in laboratory air environment. Monotonic tensile tests at 1200 °C were also conducted. Fracture surfaces were examined to analyze failure and damage mechanisms. Comparisons with counterparts from unnotched geometry showed N720/A is mildly sensitive to the sharp notch under monotonic tensile, creep and fatigue Loading Conditions. The ultimate tensile strength of the composite was reduced by about 15% in the presence of the sharp notch. The rupture strength of the sharp notched geometry was reduced by about 15% of unnotched geometry for a given rupture time. The fatigue strength was reduced by about 20% of unnotched geometry for a given number of cycles to failure. Deformation under Cyclic Loading Condition had contributions both from fatigue and creep. Damage mechanisms were identical under Cyclic and sustained Loading Conditions.
B H Boyer - One of the best experts on this subject based on the ideXlab platform.
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Cyclic and sustained Loading behaviors of oxide oxide nextel 720 alumina composite with double edge sharp notch
Composites Part A-applied Science and Manufacturing, 2012Co-Authors: S Mall, B H BoyerAbstract:Abstract This study investigated an oxide/oxide CMC consisting of Nextel™720 (meta-stable mullite) fibers in alumina matrix, N720/A, with 0°/90° fiber orientation having double edge sharp notch under sustained and Cyclic Loading Conditions at 1200 °C in laboratory air environment. Monotonic tensile tests at 1200 °C were also conducted. Fracture surfaces were examined to analyze failure and damage mechanisms. Comparisons with counterparts from unnotched geometry showed N720/A is mildly sensitive to the sharp notch under monotonic tensile, creep and fatigue Loading Conditions. The ultimate tensile strength of the composite was reduced by about 15% in the presence of the sharp notch. The rupture strength of the sharp notched geometry was reduced by about 15% of unnotched geometry for a given rupture time. The fatigue strength was reduced by about 20% of unnotched geometry for a given number of cycles to failure. Deformation under Cyclic Loading Condition had contributions both from fatigue and creep. Damage mechanisms were identical under Cyclic and sustained Loading Conditions.
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Cyclic and sustained Loading behaviors of oxide/oxide Nextel™720/alumina composite with double edge sharp notch
Composites Part A: Applied Science and Manufacturing, 2012Co-Authors: S Mall, B H BoyerAbstract:Abstract This study investigated an oxide/oxide CMC consisting of Nextel™720 (meta-stable mullite) fibers in alumina matrix, N720/A, with 0°/90° fiber orientation having double edge sharp notch under sustained and Cyclic Loading Conditions at 1200 °C in laboratory air environment. Monotonic tensile tests at 1200 °C were also conducted. Fracture surfaces were examined to analyze failure and damage mechanisms. Comparisons with counterparts from unnotched geometry showed N720/A is mildly sensitive to the sharp notch under monotonic tensile, creep and fatigue Loading Conditions. The ultimate tensile strength of the composite was reduced by about 15% in the presence of the sharp notch. The rupture strength of the sharp notched geometry was reduced by about 15% of unnotched geometry for a given rupture time. The fatigue strength was reduced by about 20% of unnotched geometry for a given number of cycles to failure. Deformation under Cyclic Loading Condition had contributions both from fatigue and creep. Damage mechanisms were identical under Cyclic and sustained Loading Conditions.
Zhirui Wang - One of the best experts on this subject based on the ideXlab platform.
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Cyclic stress strain response and microstructure evolution of polycrystalline cu under pure compressive Cyclic Loading Condition
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Tzu-yin Jean Hsu, Zhirui WangAbstract:Abstract The Cyclic deformation response, CSSC behavior and microstructural evolution of oxygen free high conductivity polycrystalline copper samples were investigated under pure compression fatigue Conditions. The results were compared with the observations made under symmetrical and pulsating tension fatigue. It was found that the Cyclic deformation response, Cyclic stress–strain curve and microstructural evolution of copper for pure compression fatigue Condition are substantially different from those for push–pull fatigue. Unlike the symmetrical fatigue, rapid hardening and Cyclic creep were observed in all tested compression fatigue Conditions. To track surface micro-structural changes, optical and scanning electron microscopy (SEM), and atomic force measurement (AFM) were utilized. Dislocation structures were also examined using a transmission electron microscope (TEM) for different peak Conditions after different numbers of cycles. The observations showed that Cyclic plastic deformation accommodation by the material was not majorly contributed by the dislocation activities as evidenced by the very moderate slip activities on the surface as well as the lack of persistent slip band dislocation structures. Instead, Cyclic creep was found to be the major form of plastic strain accommodation, which was found to be introduced though grain boundary activities, i.e. grain boundary extrusions.
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Cyclic stress–strain response and microstructure evolution of polycrystalline Cu under pure compressive Cyclic Loading Condition
Materials Science and Engineering: A, 2014Co-Authors: Tzu-yin Jean Hsu, Zhirui WangAbstract:Abstract The Cyclic deformation response, CSSC behavior and microstructural evolution of oxygen free high conductivity polycrystalline copper samples were investigated under pure compression fatigue Conditions. The results were compared with the observations made under symmetrical and pulsating tension fatigue. It was found that the Cyclic deformation response, Cyclic stress–strain curve and microstructural evolution of copper for pure compression fatigue Condition are substantially different from those for push–pull fatigue. Unlike the symmetrical fatigue, rapid hardening and Cyclic creep were observed in all tested compression fatigue Conditions. To track surface micro-structural changes, optical and scanning electron microscopy (SEM), and atomic force measurement (AFM) were utilized. Dislocation structures were also examined using a transmission electron microscope (TEM) for different peak Conditions after different numbers of cycles. The observations showed that Cyclic plastic deformation accommodation by the material was not majorly contributed by the dislocation activities as evidenced by the very moderate slip activities on the surface as well as the lack of persistent slip band dislocation structures. Instead, Cyclic creep was found to be the major form of plastic strain accommodation, which was found to be introduced though grain boundary activities, i.e. grain boundary extrusions.
Yun Lu - One of the best experts on this subject based on the ideXlab platform.
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an experimental investigation on the shear mechanism of fatigue damage in rock joints under pre peak Cyclic Loading Condition
International Journal of Fatigue, 2018Co-Authors: Yun LuAbstract:Abstract In this study, the shear mechanism of fatigue damage in rock joints with first-order and second-order triangular asperities under pre-peak Cyclic Loading Conditions is investigated in laboratory. A monotonic shear test is firstly conducted to determine the shear strength in rock samples containing joints with different orders of asperities. Secondly, influence of the pre-peak Cyclic Loading Conditions with various numbers of cycles on the shear mechanism of fatigue damage in rock joints is studied at constant normal stress. In the Cyclic Loading Conditions, two consecutive steps, such as load-controlled and displacement-controlled, are applied in tests. The load-controlled step is used to achieve the cycles of pre-peak Loading in shear tests, and the displacement-controlled step is then applied to realize the final failure of rock samples with constant rate of 0.5 mm / min . Moreover, the effects of shear Loading rates, numbers of cycle and Cyclic shear Loading magnitude on fatigue damage, peak shear strength and residual shear strength of rock joints are researched. We found that fatigue damage occurs at the second-order asperities in the upper and lower blocks within low number of cycles, but the fatigue cracks initiated with initiation angle of 90 ° with respect to the first-order asperities in the upper and lower blocks coalesce with each other (or rock joints) within the high number of cycles. Meanwhile, the variations of peak shear strength and residual shear strength of rock joints within low number of cycles are also different from ones within the high number of cycles.
Tzu-yin Jean Hsu - One of the best experts on this subject based on the ideXlab platform.
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Cyclic stress strain response and microstructure evolution of polycrystalline cu under pure compressive Cyclic Loading Condition
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Tzu-yin Jean Hsu, Zhirui WangAbstract:Abstract The Cyclic deformation response, CSSC behavior and microstructural evolution of oxygen free high conductivity polycrystalline copper samples were investigated under pure compression fatigue Conditions. The results were compared with the observations made under symmetrical and pulsating tension fatigue. It was found that the Cyclic deformation response, Cyclic stress–strain curve and microstructural evolution of copper for pure compression fatigue Condition are substantially different from those for push–pull fatigue. Unlike the symmetrical fatigue, rapid hardening and Cyclic creep were observed in all tested compression fatigue Conditions. To track surface micro-structural changes, optical and scanning electron microscopy (SEM), and atomic force measurement (AFM) were utilized. Dislocation structures were also examined using a transmission electron microscope (TEM) for different peak Conditions after different numbers of cycles. The observations showed that Cyclic plastic deformation accommodation by the material was not majorly contributed by the dislocation activities as evidenced by the very moderate slip activities on the surface as well as the lack of persistent slip band dislocation structures. Instead, Cyclic creep was found to be the major form of plastic strain accommodation, which was found to be introduced though grain boundary activities, i.e. grain boundary extrusions.
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Cyclic stress–strain response and microstructure evolution of polycrystalline Cu under pure compressive Cyclic Loading Condition
Materials Science and Engineering: A, 2014Co-Authors: Tzu-yin Jean Hsu, Zhirui WangAbstract:Abstract The Cyclic deformation response, CSSC behavior and microstructural evolution of oxygen free high conductivity polycrystalline copper samples were investigated under pure compression fatigue Conditions. The results were compared with the observations made under symmetrical and pulsating tension fatigue. It was found that the Cyclic deformation response, Cyclic stress–strain curve and microstructural evolution of copper for pure compression fatigue Condition are substantially different from those for push–pull fatigue. Unlike the symmetrical fatigue, rapid hardening and Cyclic creep were observed in all tested compression fatigue Conditions. To track surface micro-structural changes, optical and scanning electron microscopy (SEM), and atomic force measurement (AFM) were utilized. Dislocation structures were also examined using a transmission electron microscope (TEM) for different peak Conditions after different numbers of cycles. The observations showed that Cyclic plastic deformation accommodation by the material was not majorly contributed by the dislocation activities as evidenced by the very moderate slip activities on the surface as well as the lack of persistent slip band dislocation structures. Instead, Cyclic creep was found to be the major form of plastic strain accommodation, which was found to be introduced though grain boundary activities, i.e. grain boundary extrusions.
