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Shaking table test of composite foundation reinforcement of saturated silty soil for high speed railway

JIANG Guanlu, LIU Xianfeng, ZHANG Jianwen, ZHAO Ruyi

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 353-360 doi: 10.1007/s11709-007-0047-6

摘要： Three shaking table model tests were conducted with a geometrical scale of 1:10 using a large-scale laminar shear box to investigate the reinforcement effects of compacted gravel column-net composite foundation and cement fly-ash gravel (CFG) column-net composite foundation on the saturated silty soil along the Beijing-Shanghai High Speed Railway. The research results indicate that the increase in excess pore water pressure can be restrained effectively by the compacted gravel column-net composite foundation to improve the anti-liquefaction ability of the ground, and that shear displacement of the ground can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the capability of resisting shear displacement of ground. Furthermore, the amplifying of response acceleration, induced by foundation liquefaction, and the settlement of foundation and subgrade can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the aseismatic property of the foundation and subgrade.

关键词： large-scale     CFG column-net     amplifying     displacement     subgrade    

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Special Column on

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 323-324 doi: 10.1007/s11709-014-0288-0

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Research and industrialization of near-net rolling technology used in shaft parts

Zhenghuan HU, Baoyu WANG, Zhenhua ZHENG

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 17-24 doi: 10.1007/s11465-018-0480-3

摘要：

Shaft part rolling is an efficient and green near-net shaping technology offering many advantages, including high production efficiency, high material utilization rate, high product quality, and excellent production environment. In this paper, the features of shaft part rolling are introduced along with the working principles of two main shaft part rolling technologies, namely, cross wedge rolling (CWR) and skew rolling (SR). In relation to this technology, some R&D achievements gained by the University of Science and Technology Beijing are summarized. Finally, the latest developments in shaft part rolling are presented, including SR steel balls, precise forming of camshaft blank by CWR, SR phosphorous copper balls at room temperature, and CWR hollow axle sleeve. Although the shaft part rolling technology has been widely used in China, it only accounts for about 15% of applicable parts at present. Nevertheless, this technology has broad application prospects.

关键词： cross wedge rolling     skew rolling     near-net rolling     shaft part    

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Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 162-172 doi: 10.1007/s11705-009-0267-5

摘要： Bubble columns are widely used in chemical and biochemical processes due to their excellent mass and heat transfer characteristics and simple construction. However, their fundamental hydrodynamic behaviors, which are essential for reactor scale-up and design, are still not fully understood. To develop design tools for engineering purposes, much research has been carried out in the area of computational fluid dynamics (CFD) modeling and simulation of gas-liquid flows. Due to the importance of the bubble behavior, the bubble size distribution must be considered in the CFD models. The population balance model (PBM) is an effective approach to predict the bubble size distribution, and great efforts have been made in recent years to couple the PBM into CFD simulations. This article gives a selective review of the modeling and simulation of bubble column reactors using CFD coupled with PBM. Bubble breakup and coalescence models due to different mechanisms are discussed. It is shown that the CFD-PBM coupled model with proper bubble breakup and coalescence models and interphase force formulations has the ability of predicting the complex hydrodynamics in different flow regimes and, thus, provides a unified description of both the homogeneous and heterogeneous regimes. Further study is needed to improve the models of bubble coalescence and breakup, turbulence modification in high gas holdup, and interphase forces of bubble swarms.

关键词： bubble column     computational fluid dynamics     bubble breakup and coalescence     population balance model     bubble size distribution    

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Special Column on Multiscale Stochastic Finite Element Method

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 105-106 doi: 10.1007/s11709-015-0297-7

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Special column: solar energy conversion

Yun Hang HU, Fangming JIN

《能源前沿（英文）》 2019年 第13卷 第2期   页码 205-206 doi: 10.1007/s11708-019-0636-9

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Seismic tests of post-tensioned self-centering building frames with column and slab restraints

Chung-Che CHOU, Jun-Hen CHEN

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 323-334 doi: 10.1007/s11709-011-0119-5

摘要： Post-tensioned (PT) self-centering moment frames have been developed as an alternative to typical moment-resisting frames (MRFs) for earthquake resistance. When a PT frame deforms laterally, gaps between the beams and columns open. However, the gaps are constrained by the columns and the slab in a real PT self-centering building frame. This paper presents a methodology for evaluating the column restraint and beam compression force based on the column deformation and gap openings at all stories. The method is verified by cyclic tests of a full-scale, two-bay by one-story PT frame. Moreover, a sliding slab is proposed to minimize restraints on the expansion of the PT frame. Shaking table tests were conducted on a reduced-scale, two-by-two bay one-story specimen, which comprises one PT frame and two gravitational frames. The PT frame and gravitational frames are self-centering throughout the tests, responding in phase with only minor differences in peak drifts caused by expansion of the PT frame. When the specimen is excited by a simulation of the 1999 Chi-Chi earthquake with a peak ground acceleration of 1.87 g, the maximum interstory drift and the residual drift are 7.2% and 0.01%, respectively.

关键词： post-tensioned frame     frame expansion     column restraint     sliding slab     frame test     shake table test    

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Experimental and numerical analysis of beam to column joints in steel structures

Gholamreza ABDOLLAHZADEH, Seyed Mostafa SHABANIAN

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 642-661 doi: 10.1007/s11709-017-0457-z

摘要： The behaviors such as extreme non-elastic response, constant changes in roughness and resistance, as well as formability under extreme loads such as earthquakes are the primary challenges in the modeling of beam-to-column connections. In this research, two modeling methods including mechanical and neural network methods have been presented in order to model the complex hysteresis behavior of beam-to-column connections with flange plate. First, the component-based mechanical model will be introduced in which every source of transformation has been shown only with geometrical and material properties. This is followed by the investigation of a neural network method for direct extraction of information out of experimental data. For the validation of behavioral curves as well as training of the neural network, the experiments were carried out on samples with real dimensions of beam-to-column connections with flange plate in the laboratory. At the end, the combinational modeling framework is presented. The comparisons reveal that the combinational modeling is able to display the complex narrowed hysteresis behavior of the beam-to-column connections with flange plate. This model has also been successfully employed for the prediction of the behavior of a newly designed connection.

关键词： beam to column connections     experiments     component method     neural network model     combinational modeling    

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Effects of hydraulic retention time on net present value and performance in a membrane bioreactor treating

Dawei Yu, Jianxing Wang, Libin Zheng, Qianwen Sui, Hui Zhong, Meixue Cheng, Yuansong Wei

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1280-7

摘要： Abstract • The membrane bioreactor cost decreased by 38.2% by decreasing HRT from 72 h to 36 h. • Capital and operation costs contributed 62.1% and 37.9% to decreased costs. • The membrane bioreactor is 32.6% cheaper than the oxidation ditch for treatment. • The effluent COD also improved from 709.93±62.75 mg/L to 280±17.32 mg/L. • Further treatment also benefited from lower pretreatment investment. A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost. Different hydraulic retention times (72–24 h) were subjected to a flat-sheet membrane bioreactor updated from an existing 72 h oxidation ditch treating antibiotic production wastewater. Field experimental data from the membrane bioreactor, both full-scale (500 m3/d) and pilot (1.0 m3/d), were used to calculate the net present value (NPV), incorporating both capital expenditure (CAPEX) and operating expenditure. The results showed that the tank cost was estimated above membrane cost in the membrane bioreactor. The decreased hydraulic retention time from 72 to 36 h reduced the NPV by 38.2%, where capital expenditure contributed 24.2% more than operational expenditure. Tank construction cost was decisive in determining the net present value contributed 62.1% to the capital expenditure. The membrane bioreactor has the advantage of a longer lifespan flat-sheet membrane, while flux decline was tolerable. The antibiotics decreased to 1.87±0.33 mg/L in the MBR effluent. The upgrade to the membrane bioreactor also benefited further treatments by 10.1%–44.7% lower direct investment.

关键词： Antibiotic production wastewater     Net present value     Membrane bioreactor     Hydraulic retention time     Pollutant removal    

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Investigation of the interior RC beam-column joints under monotonic antisymmetrical load

Fei GAO, Zhiqiang TANG, Biao HU, Junbo CHEN, Hongping ZHU, Jian MA

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1474-1494 doi: 10.1007/s11709-019-0572-0

摘要： The paper presents numerical findings of reinforced concrete interior beam-column joints under monotonic antisymmetrical load. The finite element models considered compression and tension damage were calibrated by test results in terms of the load-displacement, failure modes, and strains of longitudinal steel. The emphasis was put on studying the effects of hoop reinforcement ratio in joint core and the axial compression ratio on the responses of the joints. The results show that, in addition to the truss and strut-and-tie mechanisms, the confinement mechanism also existed in the joint core. A certain amount of stirrup is not only able to enhance the confinement in joint core, undertake a part of shear force and thus to increase the shear capacity, prevent the outward buckling of steel bars in column, improve the stress distribution in joint core, delay cracking and restrain the propagation of cracks, but also to increase the yield load, decrease the yield displacement of beam and improve the joint ductility. However, excessive horizontal stirrups contribute little to the joint performance. In a certain range, larger axial compression ratio is beneficial for the joint mechanical behavior, while it is negative when axial compression ratio is too large.

关键词： RC beam-column joint     reinforcement ratio in joint core     axial compression ratio     finite element     test    

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Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 461-471 doi: 10.1007/s11705-010-0517-6

摘要： The recent studies of direct alcohol/ether synthesis process in slurry reactors were reviewed, and the research work in our laboratory was carried out in this paper. a global kinetics model for direct dimethyl ether (DME) synthesis from syngas over a novel Cu-Zn-Al-Zr slurry catalyst was established according to the total of 25 experimental data, and a steady-state one-dimensional mathematical model was further developed in bubble column slurry reactor (BCSR), which was assumed that the bubble phase was plug flow, and the liquid phase was fully mixed flow. The numerical simulations of reactor design of 100000 t/a dimethyl ether pilot plant indicate that higher pressure and lower temperature were favorable to the increase of CO conversion, selectivity of dimethyl ether, product yield and height of slurry bed. The optimal operating conditions for DME synthesis process were obtained: reaction temperature at 240°C, reactor pressure at 5 MPa and reactor diameter of 2.5 m.

关键词： syngas     alcohol/ether fuel     slurry catalyst     bubble column slurry reactor     global kinetics     mathematical model    

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Special issue: Near-net shaping technology

Dequn LI, Dongming GUO, Qingxue HUANG, Yanchun LOU

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 1-2 doi: 10.1007/s11465-018-0497-7

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Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete column

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1415-1425 doi: 10.1007/s11709-021-0786-9

摘要： To study the behavior of coral aggregate concrete (CAC) column under axial and eccentric compression, the compression behavior of CAC column with different types of steel and initial eccentricity (ei) were tested, and the deformation behavior and ultimate bearing capacity (Nu) were studied. The results showed that as the ei increases, the Nu of CAC column decreases nonlinearly. Besides, the steel corrosion in CAC column is severe, which reduces the steel section and steel strength, and decreases the Nu of CAC column. The durability of CAC structures can be improved by using new organic coated steel. Considering the influence of steel corrosion and interfacial bond deterioration, the calculation models of Nu under axial and eccentric compression were presented.

关键词： coral aggregate concrete column     axial compression     eccentric compression     steel corrosion     calculation model    

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基于时间-有色Petri网的电梯系统的建模与分析

宗群,窦立谦,程义菊

《中国工程科学》 2004年 第6卷 第12期   页码 51-55

摘要：

根据时间Petri网和有色Petri网的知识，提出了基于时间-有色Petri网（TCPN）的电梯运行模型。依据此模型将电梯在每层的运行情况分类说明。电梯如何运行是由控制命令统一调度，控制命令是由与电梯运行状态相应的颜色集组成。最后举例说明此模型可在单台电梯控制系统和电梯群控系统中应用。

关键词： Petri网     时间-有色Petri网     电梯模型     电梯运行    

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Determining casting defects in near-net shape casting aluminum parts by computed tomography

Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 48-52 doi: 10.1007/s11465-018-0493-y

摘要：

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.

关键词： near-net shape casting     aluminum parts     casting defects     low pressure die casting     die casting     semi-solid casting     computed tomography    

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标题 作者 时间 类型 操作

Shaking table test of composite foundation reinforcement of saturated silty soil for high speed railway

JIANG Guanlu, LIU Xianfeng, ZHANG Jianwen, ZHAO Ruyi

期刊论文

Special Column on

期刊论文

Research and industrialization of near-net rolling technology used in shaft parts

Zhenghuan HU, Baoyu WANG, Zhenhua ZHENG

期刊论文

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

期刊论文

Special Column on Multiscale Stochastic Finite Element Method

期刊论文

Special column: solar energy conversion

Yun Hang HU, Fangming JIN

期刊论文

Seismic tests of post-tensioned self-centering building frames with column and slab restraints

Chung-Che CHOU, Jun-Hen CHEN

期刊论文

Experimental and numerical analysis of beam to column joints in steel structures

Gholamreza ABDOLLAHZADEH, Seyed Mostafa SHABANIAN

期刊论文

Effects of hydraulic retention time on net present value and performance in a membrane bioreactor treating

Dawei Yu, Jianxing Wang, Libin Zheng, Qianwen Sui, Hui Zhong, Meixue Cheng, Yuansong Wei

期刊论文

Investigation of the interior RC beam-column joints under monotonic antisymmetrical load

Fei GAO, Zhiqiang TANG, Biao HU, Junbo CHEN, Hongping ZHU, Jian MA

期刊论文

Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

期刊论文

Special issue: Near-net shaping technology

Dequn LI, Dongming GUO, Qingxue HUANG, Yanchun LOU

期刊论文

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete column

期刊论文

基于时间-有色Petri网的电梯系统的建模与分析

宗群,窦立谦,程义菊

期刊论文

Determining casting defects in near-net shape casting aluminum parts by computed tomography

Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER

期刊论文