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Bai Chongxi - One of the best experts on this subject based on the ideXlab platform.
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research on ultimate Stress Increment in cfrp tendons for simply supported beams and slabs
Concrete, 2013Co-Authors: Bai ChongxiAbstract:Ultimate Stress Increment of unbonded CFRP tendon was calculated by full-range analysis programs of concrete simply supported beams and slabs partially preStressed with unbonded CFRP tendons.The basic factors such as modulus of elasticity for CFRP tendon,preStressing reinforcement index,non-preStressed reinforcement index,loading type,ratio of span to depth and profile of tendons affecting the law of ultimate Stress Increment of unbonded CFRP tendons were presented.Key factors which had major affect on ultimate Stress Increment of unbonded CFRP tendons were defined.Based on the results of simulations analysis,making key parameters as independent variable,the calculation formulas of ultimate Stress Increment of unbonded CFRP tendons in simply supported beams and slabs were proposed,and they can provide the basis for correctly calculating flexural load bearing capacity of beams and slabs.
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factors of affecting Stress Increment in cfrp tendons for simply supported beams and slabs
Low Temperature Architecture Technology, 2013Co-Authors: Bai ChongxiAbstract:Comprehension of law of Stress Increment of unbonded CFRP tendons at service stage is the basis to exactly calculate stiffness and crack width of concrete beams and slabs partially preStressed with unbonded CFRP tendons.Based on full-range analysis programs of concrete simply supported beams and slabs partially preStressed with unbonded CFRP tendons,the basic factors such as the ratio of modulus of elasticity for CFRP tendon to that for steel,non-preStressed reinforcement index,preStressing reinforcement index,loading type,ratio of span to depth and profile of tendons affecting the law of Stress Increment of unbonded CFRP tendons at service stage are presented.
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law of Stress Increment in unbonded cfrp tendons in continuous concrete beams and slabs
Journal of the China Railway Society, 2010Co-Authors: Bai ChongxiAbstract:The bearing capacity and durability decline in structures caused by corrosion of preStressing tendons can be effectively avoided with CFRP(Carbon Fiber Reinforced Polymer) tendons used as preStressing tendons instead of high strength steel bars and with epoxy coated steel bars as non-preStressed reinforcements.Comprehension of the law of the Stress Increment of unbonded CFRP tendons is the basis to exactly calculate the stiffness,crack width and flexural load bearing capacity of the unbonded preStressed concrete beam and slab preStressed with CFRP tendons.Because the plane-section assumption is not applicable to unbonded tendons in loading of unbonded preStressed concrete beams and slabs,the constant stiffness method and moment-curvature nonlinear analysis method were used to compile the calculation programs of the law of the Stress Increment of unbonded CFRP tendons in serviceability limit states and ultimate limit states.On the basis of a large number of calculated results,the basic factors such as the tension zone indices,the non-preStressed reinforcement ratio,preStressing reinforcement ratio,modulus of elasticity of CFRP tendons,loading types,ratio of span to height and height from the concrete extreme fiber to the centroid of the preStressing tendons,and the parameters of the non-preStressed reinforcement of the compression zone and compression flange affecting the Stress Increment of unbonded CFRP tendons in continuous beams and slabs in serviceability limit states and normal-section ultimate limit states were presented.The calculation formulas of the Stress Increment of unbonded CFRP tendons in partially preStressed concrete continuous beams and slabs in serviceability limit states and normal-section ultimate limit states were proposed.
Teruyuki Kato - One of the best experts on this subject based on the ideXlab platform.
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Prediction of Stress field in Japan using GPS network data
Earth Planets and Space, 2020Co-Authors: Muneo Hori, Toshio Kameda, Teruyuki KatoAbstract:The applicability of a new inversion method to the Japanese Islands is examined. This method can compute a self-equilibrating Stress Increment from a strain Increment, and the validity of the method is verified for metal-like-materials. Some modifications will be needed in applying the new inversion method to the Japanese Islands when a strain Increment measured by the GPS array is used as input data. In this paper, we try to compute the Stress Increment associated with a measured displacement Increment. It is shown that the inversion works and the Stress Increment is computed. The validity of the results, however, cannot be verified right now. Some information on regional constitutive relations is obtained from the measured strain Increment and the predicted Stress Increment. We discuss the applicability of the inversion method, and clarify modifications that are needed for more reliable prediction.
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application of the inversion method to a gps network for estimating the Stress Increment in japan
Geophysical Journal International, 2001Co-Authors: Muneo Hori, Toshio Kameda, Teruyuki KatoAbstract:SUMMARY This paper examines the applicability of an inversion method of identifying Stress distribution to the Japanese Islands, whose deformation is measured by the nationwide GPS array. The present inversion method is different from ordinary inversion, which requires a parametrization of constitutive relations, even though it is applicable only in the 2-D state. It is rigorously shown that Stress can be found without using constitutive relations, and the validity and usefulness are verified by carrying out a numerical simulation and a model experiment for a certain class of materials. For the GPS data, the inversion method can predict the Stress Increment distribution that is associated with the measured displacement Increment. Under assumptions of a plane Stress state for the Incremental deformation and no volumetric inelastic deformation, the Stress Increment is computed from the GPS array data measured during 1997 and 1998; from the viewpoint of numerical analysis, the validity of the solutions is examined by changing the discretization scale, boundary conditions and other parameters. Regional constitutive relations are deduced from relations between the measured strain Increment and the inverted Stress Increment. While further studies are definitely needed, the results of the numerical simulation suggest the potential usefulness of the present inversion method. The limitations of the inversion method when applied to the Japanese Islands are discussed, and necessary modifications are mentioned.
Muneo Hori - One of the best experts on this subject based on the ideXlab platform.
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Application of Stress Inversion Method to Develop Crustal Deformation Monitor of Japanese Islands
Inverse Problems in Engineering Mechanics III, 2020Co-Authors: Muneo Hori, Teruyki Kato, Kenji Oguni, Takeshi IinumaAbstract:The Stress inversion method is aimed at predicting Stress from strain for a body whose constitutive relations are not fully known. While the method is applicable only two a body in state of plane Stress or strain, it is rigorously shown that the method can determine Stress components using one relation between Stress and strain. This paper presents the application of the Stress inversion method to develop a crustal deformation monitor. This monitor estimates regional Stress Increment and constitutive relations for the Japanese Islands, making use of displacement Increment data that are measured by the nation-wide Global Positioning System (GPS) network. The distribution of regional strain and Stress Increments are calculated, and the usefulness of the Stress inversion method is discussed in developing the crustal deformation monitor.
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Prediction of Stress field in Japan using GPS network data
Earth Planets and Space, 2020Co-Authors: Muneo Hori, Toshio Kameda, Teruyuki KatoAbstract:The applicability of a new inversion method to the Japanese Islands is examined. This method can compute a self-equilibrating Stress Increment from a strain Increment, and the validity of the method is verified for metal-like-materials. Some modifications will be needed in applying the new inversion method to the Japanese Islands when a strain Increment measured by the GPS array is used as input data. In this paper, we try to compute the Stress Increment associated with a measured displacement Increment. It is shown that the inversion works and the Stress Increment is computed. The validity of the results, however, cannot be verified right now. Some information on regional constitutive relations is obtained from the measured strain Increment and the predicted Stress Increment. We discuss the applicability of the inversion method, and clarify modifications that are needed for more reliable prediction.
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application of the inversion method to a gps network for estimating the Stress Increment in japan
Geophysical Journal International, 2001Co-Authors: Muneo Hori, Toshio Kameda, Teruyuki KatoAbstract:SUMMARY This paper examines the applicability of an inversion method of identifying Stress distribution to the Japanese Islands, whose deformation is measured by the nationwide GPS array. The present inversion method is different from ordinary inversion, which requires a parametrization of constitutive relations, even though it is applicable only in the 2-D state. It is rigorously shown that Stress can be found without using constitutive relations, and the validity and usefulness are verified by carrying out a numerical simulation and a model experiment for a certain class of materials. For the GPS data, the inversion method can predict the Stress Increment distribution that is associated with the measured displacement Increment. Under assumptions of a plane Stress state for the Incremental deformation and no volumetric inelastic deformation, the Stress Increment is computed from the GPS array data measured during 1997 and 1998; from the viewpoint of numerical analysis, the validity of the solutions is examined by changing the discretization scale, boundary conditions and other parameters. Regional constitutive relations are deduced from relations between the measured strain Increment and the inverted Stress Increment. While further studies are definitely needed, the results of the numerical simulation suggest the potential usefulness of the present inversion method. The limitations of the inversion method when applied to the Japanese Islands are discussed, and necessary modifications are mentioned.
Wojciech Politalski - One of the best experts on this subject based on the ideXlab platform.
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The loading pattern’s influence on the Stress Increment in preStressing steel and bending moment resistance in multi-span members post-tensioned with unbonded tendons.
2015Co-Authors: Wojciech PolitalskiAbstract:The loading pattern’s influence on the Stress Increment in preStressing steel and bending moment resistance in multi-span members post-tensioned with unbonded tendons.
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the loading pattern s influence on the Stress Increment in preStressing steel and bending moment resistance in multi span members post tensioned with unbonded tendons
Czasopismo Techniczne. Budownictwo, 2015Co-Authors: Wojciech PolitalskiAbstract:The loading pattern’s influence on the Stress Increment in preStressing steel and bending moment resistance in multi-span members post-tensioned with unbonded tendons.
Hideharu Nakashima - One of the best experts on this subject based on the ideXlab platform.
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Creep deformation characterization of heat resistant steels by Stress change test
Journal of The Society of Materials Science Japan, 2009Co-Authors: Hiroyuki Hayakawa, Satoshi Nakashima, Junichi Kusumoto, Akihiro Kanaya, Yoshihiro Yakabe, Hideharu NakashimaAbstract:In order to evaluate creep deformation mechanism of heat resistant steels, Stress change tests were conducted during creep tests. In this study, it was confirmed that the dislocation behavior during the creep tests was in viscous manner, because no instantaneous plastic strain was observed at Stress Increments. Transient behavior was observed after Stress changes for all kinds of steels in this work. Mobility of dislocation was evaluated by the observed backward creep behavior after Stress reduction. Internal Stress was evaluated by the change of creep rate in Stress Increment, and mobile dislocation density was evaluated with the estimated mobility of dislocation and the change of creep rate in Stress Increment. It was found that the variation of mobile dislocation density during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of heat resistant steels investigated in this work. The mobility of dislocation showed a good correlation with 1/T and it is related with the amount of solute Mo that is a solution strengthening element. Microstructures of crept specimens were observed by TEM to discuss the validation of these results.
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Evaluation of Creep Deformation Mechanism of Heat Resistant Steel by Stress Change Test
Volume 9: Eighth International Conference on Creep and Fatigue at Elevated Temperatures, 2007Co-Authors: Hiroyuki Hayakawa, Satoshi Nakashima, Junichi Kusumoto, Akihiro Kanaya, Daisuke Terada, Fuyuki Yoshida, Hideharu NakashimaAbstract:In order to evaluate creep deformation mechanism of heat resistant steels, Stress change tests were conducted during creep tests. In this study, it was confirmed that the dislocation behavior during the creep tests was in viscous manner, because no instantaneous plastic strain was observed at Stress Increments. Transient behavior was observed after Stress changes for all kinds of steel in this work. Mobility of dislocation was evaluated by the observed backward creep behavior after Stress reduction. Internal Stress was evaluated by the change of creep rate in Stress Increment, and mobile dislocation density was evaluated with the estimated mobility of dislocation and the change of creep rate in Stress Increment. It was found that the variation of mobile dislocation density during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of heat resistant steels investigated in this work. The mobility of dislocation showed a good correlation with 1/T and it is related with the amount of solute Mo that is a solution strengthening element. Microstructure of crept specimens was observed by TEM to discuss the validation of these results.© 2007 ASME
