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Lateral-torsional buckling of box beam with corrugated steel webs

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Journal of Central South University 2019年第7期26卷 1946-1957页

作者： FENG Yu-lin JIANG Li-zhong zhou wang-bao HAN Jian-ping School of Civil Engineering Central South University Changsha 410075 China National Engineering Laboratory for High Speed Railway Construction Central South University Changsha 410075 China Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province Lanzhou University of Technology Lanzhou 730050 China

Corrugated steel web is folded along the longitudinal direction and has the mechanical properties such as axial compression stiffness corrugation effect, shear modulus corrugation effect, similar to that of an accordion. In order to study the lateral-torsional buckling of box beams with corrugated steel webs (BBCSW) under the action of bending moment load, the neutral equilibrium equation of BBCSW under the action of bending moment load is derived through the stationary value theory of total potential energy and further, along with taking Kollbrunner-Hajdin correction method and the mechanical properties of the corrugated web into consideration. The analytical calculation formula of lateral-torsional buckling critical bending moment of BBCSW is then obtained. The lateral-torsional buckling critical bending moment of 96 BBCSW test specimens with different geometry dimensions are then calculated using both the analytical calculation method and ANSYS finite element method. The results show that the analytical calculation results agree well with the numerical calculation results using ANSYS, thus proving the accuracy of the analytical calculation method and model simplification hypothesis proposed in this paper. Also, compared with the box beams with flat steel webs (BBFSW) with the same geometry dimensions as BBCSW, within the common range of web space-depth ratio and web span-depth ratio, BBCSW’s lateral-torsional buckling critical bending moment is larger than that of BBFSW. Moreover, the advantages of BBCSW’s stability are even more significant with the increase of web space-depth ratio and web depth-thickness ratio.

关键词： box beams with corrugated steel webs lateral-torsional buckling analytical solution accordion effect Kollbrunner-Hajdin method

Influence of mortar gap on natural vibration frequencies of high-speed railway track-bridge system

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Journal of Central South University 2022年第8期29卷 2807-2819页

作者： LIU Shao-hui JIANG Li-zhong zhou wang-bao FENG Yu-lin School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China School of Civil Engineering and Architecture East China Jiaotong University Nanchang 33013China

Based on Hamilton’s principle, the differential equations of free vibration of track-bridge systems with mortar gap are derived. Hence, a method for calculating the natural frequencies of track-bridge systems is proposed. The influence of the flexural stiffness of the track-bridge system, the vertical and longitudinal stiffness of the mortar layer,gap position and gap length on the natural frequencies of a track-bridge system is discussed. The results show that the natural frequencies of the track-bridge system are more sensitive to the change of the flexural stiffness of the bridge layer. The change of the longitudinal stiffness of the mortar layer and gap position has no obvious effect on the trackbridge system’s natural frequencies, while the interlayer vertical stiffness has a larger impact. The gap length has a more significant effect on the 4th-5th order natural frequencies of the track-bridge system. The range of the natural frequencies that are affected by the gap widens as the gap length increases.

关键词： shear deformation track-bridge system mortar gap vibration frequencies

Distortional buckling analysis of steel-concrete composite box beams considering effect of stud rotational restraint under hogging moment

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Journal of Central South University 2022年第9期29卷 3158-3170页

作者： JIANG Li-zhong NIE Lei-xin zhou wang-bao WU Xia LIU Li-li School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center for High-speed Railway Construction Technology Central South UniversityChangsha 410075China

Restrained distortional buckling is an important buckling mode of steel-concrete composite box beams(SCCBB)under the hogging *** and lateral deformation restraints of the bottom plate by the webs are essential factors affecting SCCBB distortional *** on the stationary potential energy principle,the analytical expressions for the rotational restraint stiffness(RRS)of the web upper edge as well as the RRS and the lateral restraint stiffness(LRS)of the bottom plate were ***,the SCCBB critical moment formula under the hogging moment was *** twenty specimens,the theoretical calculation method is compared with the finite-element *** indicate that the theoretical calculation method can effectively and accurately reflect the restraint effect of the studs,top steel flange,and other factors on the bottom *** the RRS and the LRS have a nonlinear coupling relationship with the external loads and the RRS of the web’s upper *** the hogging moment,the RRS of the web upper edge has a certain influence on the SCCBB distortional buckling critical *** increasing RRS of the web upper edge,the SCCBB critical moment increases at first and then tends to be stable.

关键词： steel-concrete composite box beams distortional buckling elastic rotational restraint boundary lateral restraint stiffness buckling moment

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钢管混凝土格构柱极限承载力实用计算公式

中南大学学报（自然科学版） 2011年第11期42卷 3486-3493页

作者：周旺保蒋丽忠中南大学土木工程学院高速铁路建造技术国家工程实验室湖南长沙410075

在理论分析基础上,提出钢管混凝土格构柱长细比折减系数计算模型及等效长细比计算公式,并改进等效长细比计算公式。同时,利用数值计算方法对不同混凝土强度、钢材强度、缀条横截面积、缀条布置形式、偏心率、长细比的钢管混凝土格构柱... 详细信息

在理论分析基础上,提出钢管混凝土格构柱长细比折减系数计算模型及等效长细比计算公式,并改进等效长细比计算公式。同时,利用数值计算方法对不同混凝土强度、钢材强度、缀条横截面积、缀条布置形式、偏心率、长细比的钢管混凝土格构柱构件的承载力进行仿真计算,并在改进的等效长细比基础上,分析它们对长细比折减系数的影响。结合数值计算结果及长细比折减系数计算模型,提出长细比折减系数计算公式。利用本文提出的长细比折减系数计算公式及规程CECS28:90中双系数乘积公式对构件极限承载力进行计算,并与数值计算结果及试验结果进行比较。研究结果表明:在改进的等效长细比基础上,混凝土强度、钢材强度、缀条横截面积、缀条布置形式对长细比折减系数的影响很小,可以忽略;3种计算方法计算结果吻合良好,验证了本文提出的长细比折减系数计算公式的正确性。

关键词：钢管混凝土格构柱计算方法极限承载力

四肢缀条轴压钢管混凝土格构柱承载能力分段合成法

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中南大学学报（自然科学版） 2011年第7期42卷 2063-2070页

作者：周旺保蒋丽忠中南大学土木工程学院湖南长沙410075

采用泰勒级数作为分段插值函数,在考虑多个截面的平衡条件和紧箍效应钢管混凝土应力-应变关系、剪切变形及初弯曲影响的基础上,建立杆件截面的平衡方程,提出四肢缀条轴压钢管混凝土格构柱弹塑性极限承载力数值方法,并编制相应的计算程... 详细信息

采用泰勒级数作为分段插值函数,在考虑多个截面的平衡条件和紧箍效应钢管混凝土应力-应变关系、剪切变形及初弯曲影响的基础上,建立杆件截面的平衡方程,提出四肢缀条轴压钢管混凝土格构柱弹塑性极限承载力数值方法,并编制相应的计算程序。利用提出的计算方法和编制的程序对国内已有轴压四肢钢管混凝土格构柱试件进行计算,并与现有一些规程进行比较。同时,结合数值计算结果及长细比折减系数计算模型,提出长细比折减系数计算公式。利用提出的长细比折减系数计算公式对国内已有轴压四肢钢管混凝土格构柱试件进行计算,并与数值计算结果及试验结果进行比较。研究结果表明:该方法适用于轴压长柱和短柱的弹塑性极限承载力的计算。规程计算方法结果偏于保守,计算误差大,本文方法的计算结果与试验结果较吻合;本文提出的长细比折减系数计算公式正确。

关键词：极限承载能力轴心受压钢管混凝土格构柱初弯曲

Analytical solution to mapping rail deformation under bridge transverse deformation using energy variational principle

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Journal of Central South University 2022年第8期29卷 2654-2664页

作者： LAI Zhi-peng JIANG Li-zhong zhou wang-bao LIU Xiang YU Jian ZHANG Yun-tai School of Civil Engineering Central South UniversityChangsha 410075China School of Civil Engineering Fujian University of TechnologyFuzhou 350118China

The track geometry is a critical factor that affects the running safety and riding comfort of trains moving on a high-speed railway *** study addresses the mapping relationship between the track deformation and lateral deformations of *** equations and natural boundary conditions of the track-bridge system are established based on the energy variational principle,and an analytical solution is derived for the track deformation accounting for lateral bridge deformations.A five-span simply-supported bridge with continuous welded rail has been selected as the case *** mapping rail deformations are compared to the finite element results,and both results agree well with each other,validating the analytical method proposed in this *** influence factors on the mapping rail deformation are further *** show that the mapping rail deformation is consistent with the girder displacement at the area that is away from the girder ends when the flexural stiffness ratio between the track and the bridge girder is *** interlayer stiffness has a significant effect on the mapping rail deformation when the track flexural stiffness is of a high value.

关键词： energy variational principle simply-supported beam bridge high-speed railway continuous welded rail mapping rail deformation

Effects of thrombolytic drugs and a selective endothelin-1 receptor antagonist on acute pulmonary thromboembolism in dogs

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Chinese Medical Journal 2010年第4期123卷 395-400页

作者： HAN Li LI Qing-yun zhou Ling wang Xi bao Zhi-yao LI Min WAN Huan-ying SHI Guo-chao Department of Respiratory Medicine Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200025 China

Background It has been shown that neurohumoral factors other than mechanical obstruction are involved in the pathophysiology of acute pulmonary thromboembolism （APTE）. The aim of this study was to investigate the effects of thrombolytic drugs, a selective endothelin-1 receptor （ET-1 R） antagonist alone or their combination on APTE in a canine model. Methods Twenty dogs were randomly assigned to five groups： sham, model, urokinase （UK）, BQ123, and combination （UK plus BQ123）. The dogs in the sham group underwent sham surgery. APTE was induced in the other four groups by intravenous injection of autologous blood clots. Dogs in the UK, BQ123 and combination groups received UK, BQ123 （a selective ET-1R antagonist）, or UK plus BQ123, respectively. The dogs in the model group were given saline. Mean pulmonary artery pressure （mPAP）, serum concentrations of ET-1, thromboxane （TXB2）, and tumor necrosis factor （TNF）-α were determined at different time points following the induction of APTE. Results UK and BQ123 alone markedly decreased mPAP in APTE. By comparison, the reduction was more significant in the combination group. Compared with the sham group （（-0.90±0.61） mmHg）, mPAP increased by （7.44±1.04）, （3.42±1.12） and （1.14±0.55） mmHg in the model group, UK alone and BQ123 alone groups, respectively, and decreased by （2.24±0.67） mmHg in the combination group （P 〈0.01）. Serum ET-1 concentrations in the BQ123 and combination groups were （52.95±8.53） and （74.42±10.27） pg/ml, respectively, and were significantly lower than those in the model and UK groups （（84.56±7.44） and （97.66±8.31） pg/ml respectively; P 〈0.01）. Serum TNF-α concentrations were significantly lower in the BQ123 group than in the model, UK and combination groups （P 〈0.05）. Conclusions Our results indicate that the selective ET-1R antagonist BQ123 not only reduces the increase of mPAP and serum ET-1 level, but also inhibits the production of TNF-α, and attenuates the local inflammatory response induced by APTE.

关键词： acute pulmonary thromboembolism thrombolytics endothelin-1 receptor antagonist pulmonary artery pressure

Role of iron ore in enhancing gasification of iron coke:Structural evolution,influence mechanism and kinetic analysis

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 58-69页

作者： Jie wang Wei wang Xuheng Chen Junfang bao Qiuyue Hao Heng Zheng Runsheng Xu School of Chemistry and Materials Science Hubei Engineering UniversityXiaogan 432000China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081China Institue of Ironmaking Technology Baosteel Central Research InstituteShanghai 201999China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The utilization of iron coke provides a green pathway for low-carbon *** uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was ***,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric *** findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and *** provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron *** the heating rate in non-isothermal gasification can enhance the reactivity of iron *** metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon *** kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore ***,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.

关键词： low-carbon ironmaking iron coke gasification structural evolution kinetic model

Wavelength Tuning in the Two-Section Distributed Bragg Reflector Laser Fabricatedby Quantum-Well Intermixing

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光学学报 2003年第S1期23卷 467-468页

作者： Lu Yu, Zhang Jing, wang Wei, Zhu Hong-liang, zhou Fan, wang bao-Jun, Zhang Jing-yuan, Zhao Ling-juanNational Research Center for Optoelectronic Technology, Institute of semiconductors, The Chinese Academy of Sciences, Beijing 100083, China National Research Center for Optoelectronic Technology Institute of semiconductors The Chinese Academy of Sciences Beijing 100083 China

The two-section tunable ridge waveguide distributed Bragg reflector (DBR) lasers fabricated by strained In xGa1-xAsyP1-y The threshold current of the laser is 51mA. The tunable range of the laser is 3.2nm and the side... 详细信息

关键词： MQW for is been of DBR in Wavelength Tuning in the Two-Section Distributed Bragg Reflector Laser Fabricatedby Quantum-Well Intermixing