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Energy Principle of Corrosion Environment Accelerating Crack Propagation During Anodic Dissolution Corrosion Fatigue

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Journal of Shanghai Jiaotong university(Science) 2013年第2期18卷 190-196页

作者：黄小光许金泉冯淼林 School of Navel Architecture Ocean and Civil EngineeringShanghai Jiaotong University College of Pipeline and civil engineering China University of Petroleum

A general method to predict the crack propagation of anodic dissolution corrosion fatigue is developed in this paper. Crack propagation of corrosion fatigue is presented as the result of the synergistic interactions of mechanical and environmental factors, and corrosive environment accelerates crack propagation mainly in term of anodic dissolution. By studying the variation of mechanical energy and electrochemical energy of anodic dissolution during the crack propagation process, an explicit expression of crack propagation rate is derived by the conservation of energy. The comparisons with experimental data demonstrate the validity of the proposed model. Moreover, the applicable upper-limit crack length for steady crack propagation is determined and the crack propagation life is evaluated.

关键词： crack propagation corrosion fatigue conservation of energy anodic dissolution

Modeling the Synergetic Effect of Various Factors on Chloride Transport in Nonsaturated Concrete

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Journal of Wuhan University of Technology(Materials Science) 2016年第6期31卷 1336-1346页

作者：张小刚 LU Zhaohui 王淑萍 ZHOU Tianhai XING Feng Guangdong Provincial Key Laboratory of Durability for Marine civil engineering College of Civil Engineering Shenzhen University Shenzhen 518060 China National engineering Laboratory for High Speed Railway Construction School of Civil Engineering Central South University Changsha 410075 China College of Materials Science and engineering Chongqing University Chongqing 400045 China

Diffusion has been systematically described as the main mechanism of chloride transport in reinforced concrete（RC） structure, especially when the concrete is in a saturated state. However, the single mechanism of diffusion is not able to describe the actual chloride ingress in the nonsaturated concrete. Instead, it is dominated by the interaction of diffusion and convection. With the synergetic effects of various factors taken into account, this study aimed to modify and develop an analytical convection- diffusion coupling model for chloride transport in nonsaturated concrete. The model was verified by simulation of laboratory tests and field measurement. The results of comparison study demonstrate that the analytical model developed in this study is efficient and accurate in predicting the chloride profiles in the nonsaturated concrete.

关键词： RC structures nonsaturated concrete chloride transport synergetic effect analytical convection-diffusion model influence factors

A series solution for surface motion amplification due to underground twin tunnels:incident SV waves

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Earthquake engineering and engineering Vibration 2003年第2期2卷 289-298页

作者：梁建文张浩 Vincent W Lee Department of civil engineering Tianjin UniversityTianjin 300072China Professor Department of civil engineering Tianjin UniversityTianjin 300072China Graduate Student Department of civil engineering University of Southern CaliforniaLos AngelesCA 90089-2531USA Professor

A series solution of displacement response of the ground surface in the presence of underground twin tunnels subjected to excitation of incident plane SV waves is derived by using Fourier-Bessel series expansion *** numerical parametric study shows that underground twin tunnels significantly amplify the nearby surface ground *** is suggested that the effect of subways on ground motion should be considered when the subways are planned and designed.

关键词： underground twin tunnels surface motion plane SV wave scattering series solution

Estimation of Heights of Soil Plug Inside Bucket Foundations During Suction Penetration by Deformable Discrete Element Modeling

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Transactions of Tianjin University 2007年第4期13卷 308-312页

作者：丁红岩张浦阳 School of civil engineering Tianjin University

The soil plug phenomenon involving the rising of the surface soil inside the bucket chamber under the suction pressure and seepage forces was simulated and calculated by deformable discrete element method (DDEM) models. The seepage forces, the effective gravity of soil, the friction on the chamber wall and the suction inside the chamber are considered as the main external forces of DDEM specimen. Three typical types of soil (silty clay, silt and sand) in the Bohai Sea are set as the main environmental conditions in the formation process of soil plug. It is found that the heights of soil plug simulated by DDEM models are 161.85 mm in silty clay, 125.22 mm in silt and 167.56 mm in sand, which are close to model test results and higher than those estimated by discrete element method (DEM). DDEM is an effective method to estimate and predict the heights of soil plug before suction penetration of bucket foundations on site.

关键词： bucket foundation soil plug deformable discrete element method (DDEM) seepage force

Development of Virtual Equipment for a Hydraulic Mechanics Experiment

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Tsinghua Science and Technology 2008年第S1期13卷 261-265页

作者： CHAN Ying-Chieh CHEN Ya-Hsin KANG Shih-Chung LEE Tim-Hau Department of civil engineering Taiwan University

Laboratory class is very important in the education of hydraulic mechanics. However, it usually requires a high expenditure on equipment purchase and maintenance. Virtual equipment that renders the equipment in a virtual world and provides an interactive interface for users can be an ideal solution to reduce costs. In this research, we focus on developing virtual equipment for a Venturi tube experiment. We em-ployed multiple paper-prototypes to gather user feedback on the preliminary design. Following the final pro-totype, we then implemented the virtual equipment on computers. Interactive functions have been built into the virtual equipment. Users are able to manipulate the equipment and obtain real-time feedback as if they were using actual equipment. The results show that the development of the virtual equipment is technically feasible.

关键词： virtual reality engineering education user interface

Four-function Principle for Optimization Design of Green High Performance Massive Concrete

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Journal of Wuhan University of Technology(Materials Science) 2005年第4期20卷 93-96页

作者：朱平华 Postdoctoral Station of civil engineering Zhejiang UniversityHangzhou 310027 ChinaDepartment of Civil EngineeringYangzhou Polytechnic CollegeYangzhou 225000 China)

A four-function principle was proposed for the optimization design of green high performance massive concrete（GHPMC）based on the theory of value engineering and the adiabatic temperature change control.A set of concrete formulas were designed according to the orthogonal *** experimental results were analyzed by applying the variance analysis method to find out the effects of influential factors and determine the optimum mixture *** addition,the four-function principle was successfully applied to optimize the mixture formula in field massive concrete *** practical results show the adiabatic temperature change of massive concrete could be efficiently controlled,and the excellent durability,good workability and high compressive strength could be achieved.

关键词： four-function principle GHPMC general assessment coefficient durability adiabatic temperature change control

A stochastic based approach for a new site classification method:application to the Algerian seismic code

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Earthquake engineering and engineering Vibration 2015年第4期14卷 663-681页

作者： Mohamed Beneldjouzi Nasser Laouami civil engineering Faculty University of Sciences and Technology Houari Boumediene Earthquake engineering Applied Research Center (CGS)

Building codes have widely considered the shear wave velocity to make a reliable subsoil seismic classification, based on the knowledge of the mechanical properties of material deposits down to bedrock. This approach has limitations because geophysical data are often very expensive to obtain. Recently, other alternatives have been proposed based on measurements of background noise and estimation of the H/V amplification curve. However, the use of this technique needs a regulatory framework before it can become a realistic site classification procedure. This paper proposes a new formulation for characterizing design sites in accordance with the Algerian seismic building code (RPA99/ver.2003), through transfer functions, by following a stochastic approach combined to a statistical study. For each soil type, the deterministic calculation of the average transfer function is performed over a wide sample of 1-D soil profiles, where the average shear wave (S-W) velocity, Vs, in soil layers is simulated using random field theory. Average transfer functions are also used to calculate average site factors and normalized acceleration response spectra to highlight the amplification potential of each site type, since frequency content of the transfer function is significantly similar to that of the H/V amplification curve. Comparison is done with the RPA99/ver.2003 and Eurocode8 (EC8) design response spectra, respectively. In the absence of geophysical data, the proposed classification approach together with micro-tremor measures can be used toward a better soil classification.

关键词： random field transfer function soil classification RPA99/ ver. 2003 EC8 site factor response spectrum

Optimization of Mineralization Curing System for Efficient and Safe Utilization of Steel Slag Wastes

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Journal of Wuhan University of Technology(Materials Science) 2022年第4期37卷 595-602页

作者： YI Haihe ZHAN Qiwei YU Xiaoniu School of civil and Architectural engineering Shandong University of TechnologyZibo 255000China School of civil engineering and Architecture Jiangsu University of Science and TechnologyZhenjiang 212003China Department of civil and Environmental engineering Nanyang Technological UniversitySingapore City 639798Singapore

The crystal structure and morphology of the mineralization products were studied by scanning electron microscopy(SEM)and X-ray diffraction(XRD),and the thermal properties were studied by thermogravimetric-differential scanning calorimetry(DSC)*** changes of microorganism quantity and enzyme activity in pore solution with time were *** experimental results show that microorganism quantity and enzyme activity in pore solution reach the maximum at 50-60 h,mineralization curing begins at this time,the strength of microbial mineralized steel slag reaches the *** study provides a good selection basis for selecting the optimum mineralization system for the production of microbial mineralized steel slag *** mineralization can accelerate the rate of carbon sequestration in the mineralization *** compressive strength of steel slag with 1.5% bacterial can reach up to 55.6 *** microstructure and thermal properties of calcium carbonate precipitate induced by the enzymes of bacillus subtilis differs from the chemical precipitation in pore solution of steel *** the analysis of the mineralized products of steel slag,the reaction rate of free calcium oxide and free magnesium oxide in steel slag after the addition of microorganisms is significantly increased,which improves the stability of steel slag as cementitious ***,the production of calcium carbonate,the main mineralized product,is significantly increased.

关键词： steel slag microorganism bio-mineralization enzyme activity curing system

DME Interference mitigation for L-DACS1 based on system identification and sparse representation

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Chinese Journal of Aeronautics 2016年第6期29卷 1762-1773页

作者： Li Douzhe Wu Zhijun School of Electronic and Information engineering Tianjin University School of Electronic and Information engineering Civil Aviation University of China

L-band digital aeronautical communication system 1(L-DACS1) is a promising candidate data-link for future air-ground communication, but it is severely interfered by the pulse pairs(PPs) generated by distance measure equipment. A novel PP mitigation approach is proposed in this paper. Firstly, a deformed PP detection(DPPD) method that combines a filter bank, correlation detection, and rescanning is proposed to detect the deformed PPs(DPPs) which are caused by multiple filters in the receiver. Secondly, a finite impulse response(FIR) model is used to approximate the overall characteristic of filters, and then the waveform of DPP can be acquired by the original waveform of PP and the FIR model. Finally, sparse representation is used to estimate the position and amplitude of each DPP, and then reconstruct each DPP. The reconstructed DPPs will be subtracted from the contaminated signal to mitigate interference. Numerical experiments show that the bit error rate performance of our approach is about 5 dB better than that of recent works and is closer to interference-free environment.

关键词： DME interference L-DACS1 Least square approximations Proximal gradient algorithm Sparse representation