The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Lei Zhao - One of the best experts on this subject based on the ideXlab platform.
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Two-parameter characterization of constraint effect induced by specimen size on Creep Crack Growth
Engineering Fracture Mechanics, 2015Co-Authors: Lei Zhao, Yongdian Han, Hongyang JingAbstract:Abstract Experimental and numerical investigations on the effect of constraint induced by different specimen sizes on Creep Crack Growth had been conducted using compact tension specimen with P92 steel. The experimental results revealed that at the same C∗ values, Creep Crack Growth rates increased as specimen size increased and the difference enlarged with increasing C∗ values. In addition, the variations of constraint level Q during Creep were obtained and a modified C∗–Q approach incorporating constraint effect was proposed to predict Creep Crack Growth. In comparison with conventional single C∗ parameter approach, two parameter approach could provide more accurate Crack Growth rates.
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experimental investigation of specimen size effect on Creep Crack Growth behavior in p92 steel welded joint
Materials & Design, 2014Co-Authors: Lei Zhao, Hongyang Jing, Junjie Xiu, Yongdian HanAbstract:Abstract In order to clarify the effect of constraint induced by specimen size on Creep Crack Growth behavior of P92 steel welded joint, Creep Crack tests were carried out on the compact tension specimens with thick thickness and thin thickness, the Crack tip of which were located at different distinct zones of welded joint. Tested results revealed that even in thin thickness specimens, fine grained heat affected zone specimens exhibited a fast Creep Crack Growth rate compared with other micro-zones specimens due to a low Creep Crack resistance and a high multistress state. The fractographies of these specimens exhibited an accelerated number of spherical particles that were caused by the coalescence of Creep voids. Furthermore, the correlation of C * with Creep Crack Growth rate was dependent on specimen thickness. As the specimen thickness increased from 10 to 30 mm, the Creep Crack Growth rate increased. This was due to the increase in constraint level ahead of Crack tip during Creep Crack propagation.
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Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel
Engineering Fracture Mechanics, 2013Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel was investigated using compact tension (CT) specimen. Tensile residual stresses were generated ahead of Crack tip by loading in compression beyond yield and then unloading. The maximum region of residual stress was obtained by numerical simulations which calculated the models with various notch radiuses and penetration loads. After pre-compression, Creep Crack Growth tests were carried out on pre-compressed and original CT specimens to study the effect of residual stress. Furthermore, the corresponding approach on predicting Creep Crack Growth behavior for components with residual stress was also investigated.
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evaluation of constraint effects on Creep Crack Growth by experimental investigation and numerical simulation
Engineering Fracture Mechanics, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effects of constraint induced by Crack depth on Creep Crack behavior of P92 steel was investigated by experimental investigation and numerical simulation. Creep Crack Growth tests were carried out on compact tension specimens with different Crack depths. It revealed that the high constraint affected Creep Crack initiation time and steady Creep Crack Growth rate. Then, the Crack-opening stress distribution at Crack tip during Creep Crack Growth process was obtained by finite element method (FEM) analysis. The corresponding variation of constraint parameter Q was also obtained. Finally, a C * – Q approach was employed to characterize the Creep Crack Growth rate.
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Prediction of Creep Crack Growth behavior in ASME P92 steel welded joint
Computational Materials Science, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract In the present study, the prediction of Creep Crack Growth behavior in ASME P92 steel welded joint at 650 °C was carried out using elastic–plastic–Creep finite element method (FEM) and theoretical prediction models, respectively. Then the predicted Creep Crack Growth rate was correlated with parameter C* and compared with experimental data. It was observed that the Creep Crack Growth behaviors calculated by the FEM and predicted by the modified NSW model under plain stress condition agreed well with experimental results. Hence, the appropriate Creep residual life for the in-service components containing defects could be provided without conducting Creep Crack Growth tests. Furthermore, Creep Crack Growth behaviors of specimens with the initial Crack located in the different zones of welded joint were also calculated. The simulation results revealed that the highest Creep Crack Growth rate occurred at the interface between the fine grain heat affected zone and the base metal due to low Creep strength and high constraint.
Junjie Xiu - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of specimen size effect on Creep Crack Growth behavior in p92 steel welded joint
Materials & Design, 2014Co-Authors: Lei Zhao, Hongyang Jing, Junjie Xiu, Yongdian HanAbstract:Abstract In order to clarify the effect of constraint induced by specimen size on Creep Crack Growth behavior of P92 steel welded joint, Creep Crack tests were carried out on the compact tension specimens with thick thickness and thin thickness, the Crack tip of which were located at different distinct zones of welded joint. Tested results revealed that even in thin thickness specimens, fine grained heat affected zone specimens exhibited a fast Creep Crack Growth rate compared with other micro-zones specimens due to a low Creep Crack resistance and a high multistress state. The fractographies of these specimens exhibited an accelerated number of spherical particles that were caused by the coalescence of Creep voids. Furthermore, the correlation of C * with Creep Crack Growth rate was dependent on specimen thickness. As the specimen thickness increased from 10 to 30 mm, the Creep Crack Growth rate increased. This was due to the increase in constraint level ahead of Crack tip during Creep Crack propagation.
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Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel
Engineering Fracture Mechanics, 2013Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel was investigated using compact tension (CT) specimen. Tensile residual stresses were generated ahead of Crack tip by loading in compression beyond yield and then unloading. The maximum region of residual stress was obtained by numerical simulations which calculated the models with various notch radiuses and penetration loads. After pre-compression, Creep Crack Growth tests were carried out on pre-compressed and original CT specimens to study the effect of residual stress. Furthermore, the corresponding approach on predicting Creep Crack Growth behavior for components with residual stress was also investigated.
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evaluation of constraint effects on Creep Crack Growth by experimental investigation and numerical simulation
Engineering Fracture Mechanics, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effects of constraint induced by Crack depth on Creep Crack behavior of P92 steel was investigated by experimental investigation and numerical simulation. Creep Crack Growth tests were carried out on compact tension specimens with different Crack depths. It revealed that the high constraint affected Creep Crack initiation time and steady Creep Crack Growth rate. Then, the Crack-opening stress distribution at Crack tip during Creep Crack Growth process was obtained by finite element method (FEM) analysis. The corresponding variation of constraint parameter Q was also obtained. Finally, a C * – Q approach was employed to characterize the Creep Crack Growth rate.
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Prediction of Creep Crack Growth behavior in ASME P92 steel welded joint
Computational Materials Science, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract In the present study, the prediction of Creep Crack Growth behavior in ASME P92 steel welded joint at 650 °C was carried out using elastic–plastic–Creep finite element method (FEM) and theoretical prediction models, respectively. Then the predicted Creep Crack Growth rate was correlated with parameter C* and compared with experimental data. It was observed that the Creep Crack Growth behaviors calculated by the FEM and predicted by the modified NSW model under plain stress condition agreed well with experimental results. Hence, the appropriate Creep residual life for the in-service components containing defects could be provided without conducting Creep Crack Growth tests. Furthermore, Creep Crack Growth behaviors of specimens with the initial Crack located in the different zones of welded joint were also calculated. The simulation results revealed that the highest Creep Crack Growth rate occurred at the interface between the fine grain heat affected zone and the base metal due to low Creep strength and high constraint.
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Analysis of Creep Crack Growth behavior of P92 steel welded joint by experiment and numerical simulation
Materials Science and Engineering: A, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract High temperature Creep Crack Growth tests were carried out on standard compact specimens machined from the welded joint of ASME P92 steel pipe. The Creep Crack Growth behaviors of the distinct sub-regions of welded joint were investigated to clarify the ability of Creep Crack resistance under high temperature. In addition, good correlations between Creep Crack Growth rate and C ⁎ for different microzones of welded joint were obtained. The tested results revealed that the sub-regions of welded joint exhibited different Creep Crack behaviors and at the same value of C * the highest Creep Crack Growth rate occurred in the fine grained heat affected zone (FGHAZ) which was known as Type IV Cracking zone. Furthermore, finite element method analyses coupled with continuum damage mechanics were conducted to predict the Creep Crack Growth behavior and to study the effect of multistress state on Crack propagation.
Yongdian Han - One of the best experts on this subject based on the ideXlab platform.
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Two-parameter characterization of constraint effect induced by specimen size on Creep Crack Growth
Engineering Fracture Mechanics, 2015Co-Authors: Lei Zhao, Yongdian Han, Hongyang JingAbstract:Abstract Experimental and numerical investigations on the effect of constraint induced by different specimen sizes on Creep Crack Growth had been conducted using compact tension specimen with P92 steel. The experimental results revealed that at the same C∗ values, Creep Crack Growth rates increased as specimen size increased and the difference enlarged with increasing C∗ values. In addition, the variations of constraint level Q during Creep were obtained and a modified C∗–Q approach incorporating constraint effect was proposed to predict Creep Crack Growth. In comparison with conventional single C∗ parameter approach, two parameter approach could provide more accurate Crack Growth rates.
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experimental investigation of specimen size effect on Creep Crack Growth behavior in p92 steel welded joint
Materials & Design, 2014Co-Authors: Lei Zhao, Hongyang Jing, Junjie Xiu, Yongdian HanAbstract:Abstract In order to clarify the effect of constraint induced by specimen size on Creep Crack Growth behavior of P92 steel welded joint, Creep Crack tests were carried out on the compact tension specimens with thick thickness and thin thickness, the Crack tip of which were located at different distinct zones of welded joint. Tested results revealed that even in thin thickness specimens, fine grained heat affected zone specimens exhibited a fast Creep Crack Growth rate compared with other micro-zones specimens due to a low Creep Crack resistance and a high multistress state. The fractographies of these specimens exhibited an accelerated number of spherical particles that were caused by the coalescence of Creep voids. Furthermore, the correlation of C * with Creep Crack Growth rate was dependent on specimen thickness. As the specimen thickness increased from 10 to 30 mm, the Creep Crack Growth rate increased. This was due to the increase in constraint level ahead of Crack tip during Creep Crack propagation.
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Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel
Engineering Fracture Mechanics, 2013Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel was investigated using compact tension (CT) specimen. Tensile residual stresses were generated ahead of Crack tip by loading in compression beyond yield and then unloading. The maximum region of residual stress was obtained by numerical simulations which calculated the models with various notch radiuses and penetration loads. After pre-compression, Creep Crack Growth tests were carried out on pre-compressed and original CT specimens to study the effect of residual stress. Furthermore, the corresponding approach on predicting Creep Crack Growth behavior for components with residual stress was also investigated.
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evaluation of constraint effects on Creep Crack Growth by experimental investigation and numerical simulation
Engineering Fracture Mechanics, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effects of constraint induced by Crack depth on Creep Crack behavior of P92 steel was investigated by experimental investigation and numerical simulation. Creep Crack Growth tests were carried out on compact tension specimens with different Crack depths. It revealed that the high constraint affected Creep Crack initiation time and steady Creep Crack Growth rate. Then, the Crack-opening stress distribution at Crack tip during Creep Crack Growth process was obtained by finite element method (FEM) analysis. The corresponding variation of constraint parameter Q was also obtained. Finally, a C * – Q approach was employed to characterize the Creep Crack Growth rate.
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Prediction of Creep Crack Growth behavior in ASME P92 steel welded joint
Computational Materials Science, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract In the present study, the prediction of Creep Crack Growth behavior in ASME P92 steel welded joint at 650 °C was carried out using elastic–plastic–Creep finite element method (FEM) and theoretical prediction models, respectively. Then the predicted Creep Crack Growth rate was correlated with parameter C* and compared with experimental data. It was observed that the Creep Crack Growth behaviors calculated by the FEM and predicted by the modified NSW model under plain stress condition agreed well with experimental results. Hence, the appropriate Creep residual life for the in-service components containing defects could be provided without conducting Creep Crack Growth tests. Furthermore, Creep Crack Growth behaviors of specimens with the initial Crack located in the different zones of welded joint were also calculated. The simulation results revealed that the highest Creep Crack Growth rate occurred at the interface between the fine grain heat affected zone and the base metal due to low Creep strength and high constraint.
Hongyang Jing - One of the best experts on this subject based on the ideXlab platform.
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Two-parameter characterization of constraint effect induced by specimen size on Creep Crack Growth
Engineering Fracture Mechanics, 2015Co-Authors: Lei Zhao, Yongdian Han, Hongyang JingAbstract:Abstract Experimental and numerical investigations on the effect of constraint induced by different specimen sizes on Creep Crack Growth had been conducted using compact tension specimen with P92 steel. The experimental results revealed that at the same C∗ values, Creep Crack Growth rates increased as specimen size increased and the difference enlarged with increasing C∗ values. In addition, the variations of constraint level Q during Creep were obtained and a modified C∗–Q approach incorporating constraint effect was proposed to predict Creep Crack Growth. In comparison with conventional single C∗ parameter approach, two parameter approach could provide more accurate Crack Growth rates.
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experimental investigation of specimen size effect on Creep Crack Growth behavior in p92 steel welded joint
Materials & Design, 2014Co-Authors: Lei Zhao, Hongyang Jing, Junjie Xiu, Yongdian HanAbstract:Abstract In order to clarify the effect of constraint induced by specimen size on Creep Crack Growth behavior of P92 steel welded joint, Creep Crack tests were carried out on the compact tension specimens with thick thickness and thin thickness, the Crack tip of which were located at different distinct zones of welded joint. Tested results revealed that even in thin thickness specimens, fine grained heat affected zone specimens exhibited a fast Creep Crack Growth rate compared with other micro-zones specimens due to a low Creep Crack resistance and a high multistress state. The fractographies of these specimens exhibited an accelerated number of spherical particles that were caused by the coalescence of Creep voids. Furthermore, the correlation of C * with Creep Crack Growth rate was dependent on specimen thickness. As the specimen thickness increased from 10 to 30 mm, the Creep Crack Growth rate increased. This was due to the increase in constraint level ahead of Crack tip during Creep Crack propagation.
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Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel
Engineering Fracture Mechanics, 2013Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effect of residual stress on Creep Crack Growth behavior in ASME P92 steel was investigated using compact tension (CT) specimen. Tensile residual stresses were generated ahead of Crack tip by loading in compression beyond yield and then unloading. The maximum region of residual stress was obtained by numerical simulations which calculated the models with various notch radiuses and penetration loads. After pre-compression, Creep Crack Growth tests were carried out on pre-compressed and original CT specimens to study the effect of residual stress. Furthermore, the corresponding approach on predicting Creep Crack Growth behavior for components with residual stress was also investigated.
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evaluation of constraint effects on Creep Crack Growth by experimental investigation and numerical simulation
Engineering Fracture Mechanics, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract Effects of constraint induced by Crack depth on Creep Crack behavior of P92 steel was investigated by experimental investigation and numerical simulation. Creep Crack Growth tests were carried out on compact tension specimens with different Crack depths. It revealed that the high constraint affected Creep Crack initiation time and steady Creep Crack Growth rate. Then, the Crack-opening stress distribution at Crack tip during Creep Crack Growth process was obtained by finite element method (FEM) analysis. The corresponding variation of constraint parameter Q was also obtained. Finally, a C * – Q approach was employed to characterize the Creep Crack Growth rate.
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Prediction of Creep Crack Growth behavior in ASME P92 steel welded joint
Computational Materials Science, 2012Co-Authors: Lei Zhao, Hongyang Jing, Yongdian Han, Junjie XiuAbstract:Abstract In the present study, the prediction of Creep Crack Growth behavior in ASME P92 steel welded joint at 650 °C was carried out using elastic–plastic–Creep finite element method (FEM) and theoretical prediction models, respectively. Then the predicted Creep Crack Growth rate was correlated with parameter C* and compared with experimental data. It was observed that the Creep Crack Growth behaviors calculated by the FEM and predicted by the modified NSW model under plain stress condition agreed well with experimental results. Hence, the appropriate Creep residual life for the in-service components containing defects could be provided without conducting Creep Crack Growth tests. Furthermore, Creep Crack Growth behaviors of specimens with the initial Crack located in the different zones of welded joint were also calculated. The simulation results revealed that the highest Creep Crack Growth rate occurred at the interface between the fine grain heat affected zone and the base metal due to low Creep strength and high constraint.
Masaaki Tabuchi - One of the best experts on this subject based on the ideXlab platform.
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characterization of incubation time on Creep Crack Growth for weldments of p92
Engineering Fracture Mechanics, 2010Co-Authors: Ryuji Sugiura, Toshimitsu A Yokobori, Kazuto Suzuki, Masaaki TabuchiAbstract:Most structures are mainly fabricated by welding which are likely to be regions of Crack initiation and propagation. In such weldment, it is known that the multi-axial stress fields appear due to the plastic constraint induced by the differences in material micro-structure between the weld metal, heat affected zone (HAZ) and base metal. In the present study, the experiments of Creep Crack Growth tests and the structural mechanical analyses of weldment were conducted to understand the effects of stress multi-axiality of weldment on the characteristics of Creep Crack Growth, Creep deformation and Creep ductility. Additionally, to characterize the time of Creep Crack initiation up to the start of a brittle type Creep Crack Growth, the distribution of stress multi-axiality (TF) through the base metal, fine-grain HAZ, coarse-grain HAZ to weld metal were investigated.
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effect of local multi axial stress on Creep Crack Growth behavior in the heat affected zone
Tetsu To Hagane-journal of The Iron and Steel Institute of Japan, 2009Co-Authors: Ryuji Sugiura, Toshimitsu A Yokobori, Kazuto Suzuki, Masaaki TabuchiAbstract:Under the multi-axial stress field, Creep Crack Growth is considered to occur in brittle manner. From the view point of practical use, it is important to conduct the characterizations of the Creep Crack Growth rate and its life under the multi-axial stress field to predict the life of Creep Crack Growth. In the present study, for the welded joint of the W-added 9Cr ferritic heat-resistant steel, ASME Code Case 2179/ASTM A335 P92, Creep Crack Growth tests and 3-dimensional elastic-plastic Creep finite element analyses were conducted to clarify the effect of stress multi-axiality on Creep Crack Growth. As a result, the Creep ductility of welded joint was found to decrease and shift to the Creep brittle region as compared with that of base metal due to the large value of stress tri-axial factor TF.
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Creep Crack Growth of P92 Welds
Volume 6: Materials and Fabrication Parts A and B, 2008Co-Authors: Masataka Yatomi, Akio Fuji, Masaaki Tabuchi, Takeo Yokobori, K. Kobayashi, Y. Hasegawa, Toshimitsu YokoboriAbstract:This paper represents Creep properties and Creep Crack Growth properties for P92 welds. The CCG tests were carried out using cross-welded compact tension (C (T) specimens at several temperatures. The Crack front was located at HAZ region to simulate Type IV Crack. Finite element analysis was conducted to simulate multiaxiality in welded joints and compare the experimental results. The constitutive behaviour for these materials is described by a power law Creep model.Copyright © 2008 by ASME
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Creep Crack Growth properties for 12crwcob rotor steel using circular notched specimens
International Journal of Pressure Vessels and Piping, 2004Co-Authors: Jechang Ha, Masaaki Tabuchi, Hiromichi Hongo, Toshimitsu A Yokobori, Akio FujiAbstract:Abstract Most heat resisting materials in structural components are used under multiaxial stress conditions. It is important to evaluate the effect of multiaxial stress conditions on initiation and Growth of Creep Cracks, when laboratory data are applied to structural components. The Creep Crack Growth test using a circular notched bar (circumferentially Cracked round bar) specimen is a simple method to investigate multiaxial stress effects without using complicated test facilities. Creep Crack Growth tests have been performed using 12CrWCoB turbine rotor steel. In order to investigate the effects of multiaxial stress and specimen size on Creep Crack Growth properties, the tests were conducted for various notch depths and specimen diameters. The circular notched specimens showed brittle Crack Growth behaviour under multiaxial stress conditions. Creep Crack Growth rate was characterized in terms of the C ∗ parameter. The Creep Crack Growth rate, for the same C ∗ value, increased with increase in the initial notch depth, i.e. as the multiaxiality increased. Creep Crack Growth properties could be predicted by allowing for the decrease of Creep ductility under multiaxial conditions.
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Effect of microstructure on the characterization of Creep Crack Growth rate and rupture in TiAl intermetallic alloys
International Journal of Pressure Vessels and Piping, 2003Co-Authors: Akio Fuji, A. Toshimitsu Yokobori, Mizuki Kikuchi, Masaaki Tabuchi, Takeo YokoboriAbstract:Abstract In order to establish a standardised method of Creep Crack Growth testing for Creep brittle materials, Round Robin tests and analysis of the results were carried out using a TiAl alloy material tested at 750 °C. The TiAl intermetallic contained two different microstructures; one is fully lamellar TiAl and the other fine-grained TiAl. It is found from the results in the Round Robin tests that these materials show Creep Crack Growth different behaviour. In the present study, the characteristics of Creep Crack Growth rate and their rupture lives are considered. It is shown that the characterization of the Creep Crack Growth and the specimen failure lives using the Q ∗ parameter, Larson–Miller parameter and Creep ductility criteria are all possible.