The nonlinear analysis of reinforced concrete rectangular slabs undermonotonic transverse loads is performed by finite element method.The layered rectangu-lar element with 4 nodes and 20 degrees of freedom is develope...The nonlinear analysis of reinforced concrete rectangular slabs undermonotonic transverse loads is performed by finite element method.The layered rectangu-lar element with 4 nodes and 20 degrees of freedom is developed,in whichbending-stretching coupling effect is taken into account.An orthotropic equivalentuniaxial stress-strain constitutive model of concrete is used.A program is worked out andused to calculate two reinforced concrete slabs.The results of calculation are in goodconformity with the corresponding test results.In addition,the influence of tension stif-fening effect of cracked concrete on the results of calculation is discussed.展开更多
In this paper, we developed the theory and algorithm of an elastic one-way boundary element method（BEM） and a corresponding hybrid elastic thin-slab propagator for earth media with sharp boundaries between strong co...In this paper, we developed the theory and algorithm of an elastic one-way boundary element method（BEM） and a corresponding hybrid elastic thin-slab propagator for earth media with sharp boundaries between strong contrast media. This approach can takes the advantage of accurate boundary condition of BEM and completely overcomes the weak contrast limitation of the perturbationtheory based one-way operator approach. The one-way BEM is a smooth boundary approximation, which avoids huge matrix operations in exact full BEM. In addition, the one-way BEM can model the primary-only transmitted and reflected waves and therefore is a valuable tool in elastic imaging and inversion. Through numerical tests for some simple models,we proved the validity and efficiency of the proposed method.展开更多
By calculating the electron structures of the phases that phosphor, sulfur and alloying elements dissolving inγ-Fe, the reason why alloying elements can bring centerline segregation in continuous casting slab (CCS) w...By calculating the electron structures of the phases that phosphor, sulfur and alloying elements dissolving inγ-Fe, the reason why alloying elements can bring centerline segregation in continuous casting slab (CCS) with nA, the number of electrons on the strongest covalent bonds, and the structure formation factor S were investigated, and an electron structural criterion to control and to eliminate the centerline segregation was advanced. Basing on this, the electron structures of a part of rare earth phosphides and sulfides are calculated, the physical mechanism that rare earth elements can control the segregation of phosphor and sulfur is analyzed, and the criterion is well verified.展开更多
A 3D viscoelastic-plastic thermal-mechanical coupled finite element model was built on the basis of the secondary development of the commercial software MSC.Marc. Numerical simulations were performed to study slab bro...A 3D viscoelastic-plastic thermal-mechanical coupled finite element model was built on the basis of the secondary development of the commercial software MSC.Marc. Numerical simulations were performed to study slab broadening in the secondary cooling zone. The effects of slab width and thickness on slab broadening were considered. The obtained results reveal that the width broadening is noticeable, and the ratio of ultimate broadening slightly increases with the increase of slab width. This agrees well with the measured data in practice. There is no obvious increase in ultimate broadening when the thickness of slabs increases.展开更多
Hollow core slabs are becoming of increasing interest as the construction industry attempts to minimise the impact of its activities on the environment. By forming voids in the interior of a concrete slab, the amount ...Hollow core slabs are becoming of increasing interest as the construction industry attempts to minimise the impact of its activities on the environment. By forming voids in the interior of a concrete slab, the amount of concrete used can be reduced without significantly altering the capacity of the structure. In this study, we examined the inner force transfer mechanism of a column-supported cast-in-situ hollow core slab using finite element analysis. Both a hollow core slab and the corresponding solid slab were analysed using ANSYS and the results were compared. The orientation of the tube fillers causes the stiffness of the hollow slab to be orthotropic, potentially changing the distribution of load carried in the two orthogonal directions. Both the cross-section’s moments in the column strip and near the columns in the hollow core slab become larger than that in the solid floor. As well, the cross-section’s stiffness along the tube arrangement direction is larger than that of the radial cross-section, which causes the direction along the hole of the hollow core slab to carry more moment than the radial direction. The conversion factors of the two directions are proposed from the comparison for four typical areas of the hollow core slab, as are the moment distribution coefficients.展开更多
In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calcul...In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calculate the influence of lateral flow factors in different entry thicknesses, reductions, reduction ratios differences on both sides and width factors. Thus, the extending difference at outlet of intermediate slab in length was transformed into thickness difference on both sides by the results, and then the tilting value of roll gap reduction to control the camber was calculated. Based on the above results, the camber control model of intermediate slab in rough rolling was estab- lished. The practical application on the rough rolling mill obtained a decent control effect, and it proved that this model had a high accuracy.展开更多
The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-colu...The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-column and shearwall structure in the practical engineering,the key parameters of slab-column and shearwall structure and frame-shearwall structure such as deflection,punching shear behavior,story drift and capability curve were worked out by static plastic analysis,elastic-plastic time history analysis and pushover analysis,then the suitability of out-of-codes tall slab-column and shearwall structure was evaluated.The results show that the out-of-codes tall slab-column and shearwall structure studies could satisfy the require of deflection and punching shear behavior,the story drift under 7 degree expected rare earthquake waves could satisfy the limit value in the codes and the seismic design spectrum was crossed by the capability curve of the structure and the structure could not collapse.The conclusion is that slab-column and shearwall structure with reasonable design built in Ⅱ soil site of intensity 7 seismic fortification zone can be designed higher than the limit height in the codes.展开更多
A transient thermal model was developed for slab furnaces in Eregli Iron and Steel Works （Erdemir） in Turkey and the model was solved using the FlexPDE computer program. This program uses the finite element method. ...A transient thermal model was developed for slab furnaces in Eregli Iron and Steel Works （Erdemir） in Turkey and the model was solved using the FlexPDE computer program. This program uses the finite element method. Program codes were written to solve the temperature distribution of slabs that are put into furnace at 25 ℃ and removed at about 1 250℃. To obtain the optimum slab exit temperature variation, the necessary air temperature inside the furnace was calculated to be 1 390℃. The slab temperature versus time and the temperature variation inside the slab were depicted.展开更多
Punching shear failure of flat concrete slabs is a complex phenomenon with brittle failure mode, meaning sudden structural failure and rapid decrease of load carrying capacity. Due to these reasons, the application of...Punching shear failure of flat concrete slabs is a complex phenomenon with brittle failure mode, meaning sudden structural failure and rapid decrease of load carrying capacity. Due to these reasons, the application of appropriate punching shear reinforcement in the slabs could be essential. To obtain the required structural strength and performance in slab-column junctions, the effect of the shear reinforcement type on the punching resistance must be known. For this purpose, numerous nonlinear finite element simulations were carried out to determine the behavior and punching shear strength of flat concrete slabs with different punching shear reinforcement types. The efficiency of different reinforcement types was also determined and compared. Accuracy of the numerical simulations was verified by experimental results. Based on the comparison of numerical results,?the partial factor for the design formula used in Eurocode 2 was calculated and was found to be higher than the actual one.展开更多
Basic assumptions are proposed for the continuity model of a tubular hollow slab combined with continuity analysis and calculation of a finite-element model;the continuity Equation of a tubular hollow slab at the mino...Basic assumptions are proposed for the continuity model of a tubular hollow slab combined with continuity analysis and calculation of a finite-element model;the continuity Equation of a tubular hollow slab at the minor axis supported at two ends of the hollow axle under a vertical even load is determined and solved. The overall equivalent flexural rigidity is then determined, which provides important conditions for the continuity analysis of tubular hollow floor supported along four sides.展开更多
提出一种新型预应力钢筋混凝土叠合剪力墙,通过在预制板内布置水平预应力钢筋,降低板厚,方便运输和吊装。对剪跨比为1.5的现浇剪力墙和预应力叠合剪力墙进行了低周往复加载试验,对比分析了其破坏模式、承载力、延性和耗能能力,结果表明...提出一种新型预应力钢筋混凝土叠合剪力墙,通过在预制板内布置水平预应力钢筋,降低板厚,方便运输和吊装。对剪跨比为1.5的现浇剪力墙和预应力叠合剪力墙进行了低周往复加载试验,对比分析了其破坏模式、承载力、延性和耗能能力,结果表明叠合剪力墙与现浇剪力墙的抗震性能一致。采用有限元分析软件ABAQUS建立了剪力墙的非线性数值分析模型,基于试验结果验证了模型的正确性,并进行了轴压比、剪跨比、初始预应力等参数分析。结果表明,高轴压比及小剪跨比下叠合剪力墙的承载力及延性优于现浇剪力墙。随着初始预应力的增大,承载力提高,试件由剪切破坏转换为弯曲破坏。水平预应力筋延缓了叠合剪力墙斜向裂缝的发展,提高了抗剪承载力,改变了剪力墙的破坏模式,建议张拉控制应力取值为0.50 f ptk。展开更多
文摘The nonlinear analysis of reinforced concrete rectangular slabs undermonotonic transverse loads is performed by finite element method.The layered rectangu-lar element with 4 nodes and 20 degrees of freedom is developed,in whichbending-stretching coupling effect is taken into account.An orthotropic equivalentuniaxial stress-strain constitutive model of concrete is used.A program is worked out andused to calculate two reinforced concrete slabs.The results of calculation are in goodconformity with the corresponding test results.In addition,the influence of tension stif-fening effect of cracked concrete on the results of calculation is discussed.
基金supported by National Scientific Foundation of China with Grant No. 41774067
文摘In this paper, we developed the theory and algorithm of an elastic one-way boundary element method（BEM） and a corresponding hybrid elastic thin-slab propagator for earth media with sharp boundaries between strong contrast media. This approach can takes the advantage of accurate boundary condition of BEM and completely overcomes the weak contrast limitation of the perturbationtheory based one-way operator approach. The one-way BEM is a smooth boundary approximation, which avoids huge matrix operations in exact full BEM. In addition, the one-way BEM can model the primary-only transmitted and reflected waves and therefore is a valuable tool in elastic imaging and inversion. Through numerical tests for some simple models,we proved the validity and efficiency of the proposed method.
基金the Natural Science Foundation of Liaoning under grant No.20022150 the National Natural Science Foundation of China under grant No.50271030.
文摘By calculating the electron structures of the phases that phosphor, sulfur and alloying elements dissolving inγ-Fe, the reason why alloying elements can bring centerline segregation in continuous casting slab (CCS) with nA, the number of electrons on the strongest covalent bonds, and the structure formation factor S were investigated, and an electron structural criterion to control and to eliminate the centerline segregation was advanced. Basing on this, the electron structures of a part of rare earth phosphides and sulfides are calculated, the physical mechanism that rare earth elements can control the segregation of phosphor and sulfur is analyzed, and the criterion is well verified.
基金supported by the Key Projects in the National Science & Technology Pillar Program during the 11th Five-Year Plan Period of China (No.2006BAE03A04)
文摘A 3D viscoelastic-plastic thermal-mechanical coupled finite element model was built on the basis of the secondary development of the commercial software MSC.Marc. Numerical simulations were performed to study slab broadening in the secondary cooling zone. The effects of slab width and thickness on slab broadening were considered. The obtained results reveal that the width broadening is noticeable, and the ratio of ultimate broadening slightly increases with the increase of slab width. This agrees well with the measured data in practice. There is no obvious increase in ultimate broadening when the thickness of slabs increases.
基金Project supported by the Australian Research Council Research Grant (No. DP0988940)the Natural Science Foundation of Jiangsu Province (No. BK2009394)+2 种基金the China Postdoctoral Science Foundation (No. 2011M500930)the Natural Science Surface Project of Jiangsu Provincial Universities (No. 11KJB560003)the Talent Introduction Fund of Nanjing Forestry University (No. 163050072)
文摘Hollow core slabs are becoming of increasing interest as the construction industry attempts to minimise the impact of its activities on the environment. By forming voids in the interior of a concrete slab, the amount of concrete used can be reduced without significantly altering the capacity of the structure. In this study, we examined the inner force transfer mechanism of a column-supported cast-in-situ hollow core slab using finite element analysis. Both a hollow core slab and the corresponding solid slab were analysed using ANSYS and the results were compared. The orientation of the tube fillers causes the stiffness of the hollow slab to be orthotropic, potentially changing the distribution of load carried in the two orthogonal directions. Both the cross-section’s moments in the column strip and near the columns in the hollow core slab become larger than that in the solid floor. As well, the cross-section’s stiffness along the tube arrangement direction is larger than that of the radial cross-section, which causes the direction along the hole of the hollow core slab to carry more moment than the radial direction. The conversion factors of the two directions are proposed from the comparison for four typical areas of the hollow core slab, as are the moment distribution coefficients.
基金Item Sponsored by National Key Technology Research and Development Program in 12th Five-year Plan of China(2011BAE23B00)Fundamental Research Funds for the Central Universities of China(FRF-SD-12-013B)
文摘In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calculate the influence of lateral flow factors in different entry thicknesses, reductions, reduction ratios differences on both sides and width factors. Thus, the extending difference at outlet of intermediate slab in length was transformed into thickness difference on both sides by the results, and then the tilting value of roll gap reduction to control the camber was calculated. Based on the above results, the camber control model of intermediate slab in rough rolling was estab- lished. The practical application on the rough rolling mill obtained a decent control effect, and it proved that this model had a high accuracy.
文摘The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-column and shearwall structure in the practical engineering,the key parameters of slab-column and shearwall structure and frame-shearwall structure such as deflection,punching shear behavior,story drift and capability curve were worked out by static plastic analysis,elastic-plastic time history analysis and pushover analysis,then the suitability of out-of-codes tall slab-column and shearwall structure was evaluated.The results show that the out-of-codes tall slab-column and shearwall structure studies could satisfy the require of deflection and punching shear behavior,the story drift under 7 degree expected rare earthquake waves could satisfy the limit value in the codes and the seismic design spectrum was crossed by the capability curve of the structure and the structure could not collapse.The conclusion is that slab-column and shearwall structure with reasonable design built in Ⅱ soil site of intensity 7 seismic fortification zone can be designed higher than the limit height in the codes.
文摘A transient thermal model was developed for slab furnaces in Eregli Iron and Steel Works （Erdemir） in Turkey and the model was solved using the FlexPDE computer program. This program uses the finite element method. Program codes were written to solve the temperature distribution of slabs that are put into furnace at 25 ℃ and removed at about 1 250℃. To obtain the optimum slab exit temperature variation, the necessary air temperature inside the furnace was calculated to be 1 390℃. The slab temperature versus time and the temperature variation inside the slab were depicted.
文摘Punching shear failure of flat concrete slabs is a complex phenomenon with brittle failure mode, meaning sudden structural failure and rapid decrease of load carrying capacity. Due to these reasons, the application of appropriate punching shear reinforcement in the slabs could be essential. To obtain the required structural strength and performance in slab-column junctions, the effect of the shear reinforcement type on the punching resistance must be known. For this purpose, numerous nonlinear finite element simulations were carried out to determine the behavior and punching shear strength of flat concrete slabs with different punching shear reinforcement types. The efficiency of different reinforcement types was also determined and compared. Accuracy of the numerical simulations was verified by experimental results. Based on the comparison of numerical results,?the partial factor for the design formula used in Eurocode 2 was calculated and was found to be higher than the actual one.
文摘Basic assumptions are proposed for the continuity model of a tubular hollow slab combined with continuity analysis and calculation of a finite-element model;the continuity Equation of a tubular hollow slab at the minor axis supported at two ends of the hollow axle under a vertical even load is determined and solved. The overall equivalent flexural rigidity is then determined, which provides important conditions for the continuity analysis of tubular hollow floor supported along four sides.
文摘提出一种新型预应力钢筋混凝土叠合剪力墙,通过在预制板内布置水平预应力钢筋,降低板厚,方便运输和吊装。对剪跨比为1.5的现浇剪力墙和预应力叠合剪力墙进行了低周往复加载试验,对比分析了其破坏模式、承载力、延性和耗能能力,结果表明叠合剪力墙与现浇剪力墙的抗震性能一致。采用有限元分析软件ABAQUS建立了剪力墙的非线性数值分析模型,基于试验结果验证了模型的正确性,并进行了轴压比、剪跨比、初始预应力等参数分析。结果表明,高轴压比及小剪跨比下叠合剪力墙的承载力及延性优于现浇剪力墙。随着初始预应力的增大,承载力提高,试件由剪切破坏转换为弯曲破坏。水平预应力筋延缓了叠合剪力墙斜向裂缝的发展,提高了抗剪承载力,改变了剪力墙的破坏模式,建议张拉控制应力取值为0.50 f ptk。
