Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each spec...Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Moreover, considering the four important influence factors of ULC of the joints, the ratio of chord diameter to chord thickness, the ratio of diagonal member diameter to chord member diameter, the axial load on the chord member and the gap size between the two brace members, a new prediction formula of ULC of N-joint was put forward based on numerical analysis results.The new formula was proved to be more accurate than the current Chinese design code in a wide range.展开更多
In this paper we use the Green function method to solve the problem of steady one dimensional flow of an incompressible viscous, electrically conducting fluid through a pipe with partial circular ring cross sec- tion ...In this paper we use the Green function method to solve the problem of steady one dimensional flow of an incompressible viscous, electrically conducting fluid through a pipe with partial circular ring cross sec- tion and one with annular cross section, in the presence of an applied transverse uniform magnetic field, We ob- tain analytic solutions and carry out some numerical calculations of the velocity distribution and induced magnet- ic field.展开更多
Using hybrid perturbatin_Galerkin technique,a crcular cross_section tube model with sinusoidal wall is studied.This technique can remove the limitation of small parameters for perturbation and the difficulty of select...Using hybrid perturbatin_Galerkin technique,a crcular cross_section tube model with sinusoidal wall is studied.This technique can remove the limitation of small parameters for perturbation and the difficulty of selecting good coordinate functions about Galerkin technique.The effects caused by the boundary conditions and the Reynolds number on the flow were discussed.The position of the separate and reattachment points was obtained.The tendency of the variation about the shear stress on the wall and friction factor along the axis direction were also analyzed.The results at a small parameter have good agreements with the perturbation ones.展开更多
基于对二维圆形和三维二步法圆形编织工艺与编织运动规律的分析,探讨圆形截面编织结构的共同特点,建立圆形截面编织结构数学模型,模拟编织结构中单根股线中心线的轨迹及空间位置。在Visual Studio 2019平台上利用WebGL技术和三维图形引...基于对二维圆形和三维二步法圆形编织工艺与编织运动规律的分析,探讨圆形截面编织结构的共同特点,建立圆形截面编织结构数学模型,模拟编织结构中单根股线中心线的轨迹及空间位置。在Visual Studio 2019平台上利用WebGL技术和三维图形引擎库Three.js,快速有效地呈现三维股线编织结构,大幅提高三维仿真效率。结果显示:基于广义玫瑰线数学模型对圆形截面编织结构进行三维仿真切实可行且效果良好,能较好地反映编织结构股线相互穿插的交织规律和外观特征。研究可为产业用编织绳索的建模与结构可视化奠定基础。展开更多
Tests of 4 simply supported unbonded prestressed truss concrete composite beams encased with circular steel tube were carried out. It is found that the ratio of the stress increment of the unbonded tendon to that of t...Tests of 4 simply supported unbonded prestressed truss concrete composite beams encased with circular steel tube were carried out. It is found that the ratio of the stress increment of the unbonded tendon to that of the tensile steel tube is 0.252 during the using stage,and the average crack space of beams depends on the ratio of the sum of the bottom chord steel tube's outside diameter and the secondary bottom chord steel tube's section area to the effective tensile concrete area. The coefficient of uneven crack distribution is 1.68 and the formula for the calculation of crack width is established. Test results indicate that the ultimate stress increment of unbonded tendon in the beams decreases in linearity with the increase of the composite reinforcement index β0. The pure bending region of beams accords with the plane section assumption from loading to failure. The calculation formula of ultimate stress increment of the unbonded tendon and the method to calculate the bearing capacity of normal section of beams have been presented. Besides,the method to calculate the stiffness of this sort of beams is brought forward as well.展开更多
基金Supported by National Natural Science Foundation of China (No.50608054)
文摘Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Moreover, considering the four important influence factors of ULC of the joints, the ratio of chord diameter to chord thickness, the ratio of diagonal member diameter to chord member diameter, the axial load on the chord member and the gap size between the two brace members, a new prediction formula of ULC of N-joint was put forward based on numerical analysis results.The new formula was proved to be more accurate than the current Chinese design code in a wide range.
文摘In this paper we use the Green function method to solve the problem of steady one dimensional flow of an incompressible viscous, electrically conducting fluid through a pipe with partial circular ring cross sec- tion and one with annular cross section, in the presence of an applied transverse uniform magnetic field, We ob- tain analytic solutions and carry out some numerical calculations of the velocity distribution and induced magnet- ic field.
文摘Using hybrid perturbatin_Galerkin technique,a crcular cross_section tube model with sinusoidal wall is studied.This technique can remove the limitation of small parameters for perturbation and the difficulty of selecting good coordinate functions about Galerkin technique.The effects caused by the boundary conditions and the Reynolds number on the flow were discussed.The position of the separate and reattachment points was obtained.The tendency of the variation about the shear stress on the wall and friction factor along the axis direction were also analyzed.The results at a small parameter have good agreements with the perturbation ones.
文摘基于对二维圆形和三维二步法圆形编织工艺与编织运动规律的分析,探讨圆形截面编织结构的共同特点,建立圆形截面编织结构数学模型,模拟编织结构中单根股线中心线的轨迹及空间位置。在Visual Studio 2019平台上利用WebGL技术和三维图形引擎库Three.js,快速有效地呈现三维股线编织结构,大幅提高三维仿真效率。结果显示:基于广义玫瑰线数学模型对圆形截面编织结构进行三维仿真切实可行且效果良好,能较好地反映编织结构股线相互穿插的交织规律和外观特征。研究可为产业用编织绳索的建模与结构可视化奠定基础。
文摘Tests of 4 simply supported unbonded prestressed truss concrete composite beams encased with circular steel tube were carried out. It is found that the ratio of the stress increment of the unbonded tendon to that of the tensile steel tube is 0.252 during the using stage,and the average crack space of beams depends on the ratio of the sum of the bottom chord steel tube's outside diameter and the secondary bottom chord steel tube's section area to the effective tensile concrete area. The coefficient of uneven crack distribution is 1.68 and the formula for the calculation of crack width is established. Test results indicate that the ultimate stress increment of unbonded tendon in the beams decreases in linearity with the increase of the composite reinforcement index β0. The pure bending region of beams accords with the plane section assumption from loading to failure. The calculation formula of ultimate stress increment of the unbonded tendon and the method to calculate the bearing capacity of normal section of beams have been presented. Besides,the method to calculate the stiffness of this sort of beams is brought forward as well.
