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A new elliptic-parabolic yield surface model revised by an adaptive criterion for granular soils

Science China(Technological Sciences) 2010年第8期53卷 2152-2159页

作者： LIU HanLong 1,2 ,XIAO Yang 1,2 ,LIU JinYuan 3 &LI GuoYing 4 1 Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering,Hohai university, Nanjing 210098,China 2 Geotechnical Research Institute,Hohai university,Nanjing 210098,China 3department of civil engineering,ryerson university,toronto,canada 4 department of Geotechnical engineering,Nanjing Hydraulic Research Institute,Nanjing 210014,China Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering Hohai University Nanjing China Geotechnical Research Institute Hohai University Nanjing China department of civil engineering Ryerson University Toronto Canada department of Geotechnical engineering Nanjing Hydraulic Research Institute Nanjing China

An adaptive criterion for shear yielding as well as shear failure of soils is proposed in this paper to address the fact that most criteria,including the Mohr-Coulomb criterion,the Lade criterion and the Matsuoka-Nakai criterion,cannot agree well with the experimental results when the value of the intermediate principal stress parameter is too *** new criterion can adjust an adaptive parameter based on the experimental results in order to make the theoretical calculations fit the test results more *** original elliptic-parabolic yield surface model can capture both soil contraction and dilation ***,it normally over-predicts the soil strength due to its application of the Extended Mises criterion.A new elliptic-parabolic yield surface mode is presented in this paper,which introduces the adaptive criterion in three-dimensional principal stress *** new model can well model the stress-strain behavior of soils under general stress *** to the original model which can only simulate soil behavior under triaxial compression conditions,the new model can simulate soil behaviors under both triaxial compression conditions and general stress conditions.

关键词： principal stress space intermediate principal stress yield surface failure criterion constitutive model

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THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

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Journal of Computational Mathematics 1994年第4期12卷 330-338页

作者： Kaz Adamowski(department of civil engineering university of Ottawa, Ottawa, canada)Wojciech Feluch(Institute of Environmental engineering , Technical university of Warsaw, Warsaw, Poland) university of Ottawa 加拿大 Technical university of Warsaw 波兰

The nonparametric kernel estimation of probability density function (PDF) pro-vides a uniform and accurate estimate of flood frequency-magnitude ***, the kernel estimate has the disadvantage that the smoothing factor h is estimate empirically and is not locally adjusted, thus possibly resulting in deteri oration of density estimate when PDF is not smooth and is heavy-tailed. Such a problem can be alleviate by estimating the density of a transformed random vari able, and then taking the inverse transform. A new and efficient circular transform is proposed and investigated in this paper

关键词： TRT Res THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

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Factors Affecting the Relation of Fracture Toughness V_(GC) with Critical Void Growth Ratio R_C/R_O

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Journal of Materials Science & Technology 1998年第6期14卷 574-576页

作者： Li ZHOU(department of civil engineering, Wuyi university,Jiangmen 529020, China) department of civil engineering Wuyi University Jiangmen 529020 China

The relationship between fracture toughness VGC and critical void growth RC/RO was studied for ten kinds of Steel. The macroscopic fracture toughness VGC was determined by using notched tensile specimens. and the microscopic parameters of critical void growth ratio RC/RO were quantitatively measured under SEM. Then, the coefhcient C in the relation VGC = C In(RC/RO) proposed in author's past work was specifically explored. The correlation of C with tensile proderty parameter φ=σyδ/(Eφn) was presented for the Steel investigated, and the effects of low temperature on C were also discussed. Results show that the coefficient C is linearly related to the parameter and insensitive to low temperature.

关键词： GC with Critical Void Growth Ratio R_C/R_O Factors Affecting the Relation of Fracture Toughness V

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Analysis theory of random energy of train derailment in wind

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Science China(Physics,Mechanics & Astronomy) 2010年第4期53卷 751-757页

作者： CHEN RuiLin 1,2,3 , ZENG QingYuan 3 , HUANG YunQing 1 , XIANG Jun 3 , WEN Ying 3 , GUO XiaoGang 2 , YIN ChangJun 2 , DONG Hui 2 & ZHAO Gang 4 1 Hunan Key Laboratory for Computation and Simulation in Science and engineering, Xiangtan university, Xiangtan 411105, China 2 School of civil engineering & Mechanics, Xiangtan university, Xiangtan 411105, China 3 School of civil Architecture, Central South university, Changsha 410075, China 4 AMEC, toronto M5A5G7, canada Hunan Key Laboratory for Computation and Simulation in Science and engineering Xiangtan University Xiangtan China School of civil engineering & Mechanics Xiangtan University Xiangtan China School of civil Architecture Central South University Changsha China AMEC Toronto Canada

Based on the analysis theory of random energy of train derailment, an analysis theory of random energy of train derailment in wind is suggested. Two methods are proposed -the time domain method and the frequency domain method of analysis theory of random energy of train derailment in wind. The curves of σ pw -v under various wind speeds are obtained through the computation. The original curve of σ p -v is expanded, which turns the analysis theory of random energy of train derailment into the all-weather theory. Train derailment condition has been established under wind action. The first and second criterions of train derailment have been proposed in light of wind action. The analysis of train derailment cases at home or abroad is made, in- cluding the first analysis of Xinjiang train derailment case encountered 13-level of gale, which explained the inevitability of train derailment. The analysis theory of random energy of train derailment in wind shows its validity and accuracy. The input energy σ pw of the transverse vibration of train-track(bridge)-wind system is linked to train speed. With the establishment of the analysis theory of random energy of train derailment in wind, It is likely to initiate an all-weather speed limit map for a train or any high-speed train.

关键词： train derailment analysis theory of random energy of train derailment analysis theory of random energy of train de- railment in wind train derailment condition in wind the criterion of train derailment in wind train derailment case

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HYDRODYNAMIC CHARACTERISTICS OF LAKE YANAKA

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Journal of Hydrodynamics 2001年第2期13卷 9-14页

作者： Huang Guang wei department of civil engineering, Kanazawa university, 40 20 Kodatsuno 2Chome, Kanazawa lshikawa 920 8667, Japan Nobuyuki Tamai department of civil engineering, The university of Tokyo, 7 3 1, llongo, Bunkyo ku, Tokyo, 113 8656 Dept. of civil Eng. Kanazawa Univ. Kanazawa 9208867 Japan

As part of a major effort to undersand and quantify the cnvironmental conditions in Lake Yanaka, the circulation patterns in Lake Yanaka were analyzed through the application of a three dimensional hydrodynamic model. The model was validated with field observation, and then used to study the response of the lake to different forcing. The information on flow structures obtained in the present study is useful for further study of water quality in the lake.

关键词： Lake Yanaka three dimensional model flow structures

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INCIPIENT MOTION OF NON-COHESIVE SEDIMENT UNDER ICE COVER-AN EXPERIMENTAL STUDY

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Journal of Hydrodynamics 2008年第1期20卷 117-124页

作者： WANG Jun SUI Jue-yi KARNEY Bryan W. School of civil engineering Hefei University of Technology Hefei 230009 China Environmental Science and Environmental engineering Program University of Northern British ColumbiaBritish Columbia Canada V2N 4Z9 department of civil engineering University of Toronto Toronto Ontario Canada M5S 1A4

Based on a series of experiments under both ice-covered and free surface conditions, the present article discusses the role of flow velocity and critical shear Reynolds number for incipient motion of bed material. The influence of the resistance coefficients of both the underside of the ice cover and the channel bed on the location of the maximum velocity has been discussed. In addition, the impacts of ice and composite resistance coefficients on flow velocity for incipient motion of bed material have been assessed. The diagram describing the critical shear Reynolds number and the dimensionless shear stress for the incipient motion of sediment under ice covered conditions with different under cover resistance coefficient has been established. The effects of grain size on densimetric Froude number for incipient motion of bed material have been investigated. A relationship between the densimetric Froude number for incipient motion of bed material and the median grain size of bed material as well as the roughness coefficient of channel bed and roughness coefficient of ice cover has been established.

关键词： densimetric Froude number grain size ice cover incipient motion resistance coefficient shear Reynolds number,velocity

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Guided wave propagation in multilayered piezoelectric structures

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Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2,3 & ZHANG YongLiang4 1 Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, and School of civil engineering and Mechanics, Lanzhou university, Lanzhou 730000, China 2 Key Laboratory of Soft Soils and Geoenvironmental engineering, Ministry of Education, and department of civil engineering, Zhejiang university, Hangzhou 310058, China 3 department of engineering Mechanics, Zhejiang university, Hangzhou 310027, China 4 School of civil engineering, Lanzhou Jiaotong university, Lanzhou 730070, China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou China Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou China department of engineering Mechanics Zhejiang University Hangzhou China School of civil engineering Lanzhou Jiaotong University Lanzhou China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

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Low complexity construction for quasi-cyclic low-density parity-check codes by Progressive-Block Growth

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Science China(Information Sciences) 2011年第2期54卷 371-380页

作者： REN PinYi1, YUAN Qiang2, WANG Rui1 & CAI Jun3 1School of Electronic engineering, Xi’an Jiaotong university, Xi’an 710049, China 2Wuhan Ordnance Noncommissioned Officers Academy, Wuhan 430075, China 3department of Electrical & Computer engineering, university of Manitoba, Winnipeg, Manitoba R3T 5V6, canada School of Electronic engineering Xi’an Jiaotong University Xi’an China Wuhan Ordnance Noncommissioned Officers Academy Wuhan China department of Electrical & Computer engineering University of Manitoba Winnipeg Canada

In this paper, a novel method for constructing quasi-cyclic LDPC codes with low complexity is proposed. By choosing each circulant permutation matrix sequentially, the proposed method ensures that the current circulant permutation matrix forms no cycles of length smaller than g with the existent circulant permutation matrices. The construction complexity of the proposed algorithm is much lower than that of the random construction. Simulation results show that the proposed QC-LDPC codes can outperform both the random regular LDPC codes with short to moderate block lengths, and the proposed construction method LDPC codes based on the finite geometries in terms of bit-error-rate (BER).

关键词： quasi-cyclic (QC) LDPC (low-density parity-check) codes circulant permutation matrix girth

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Irregular-Mode Cracking in Fe-3 wt pct Si Alloy

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Journal of Materials Science & Technology 2005年第3期21卷 338-342页

作者： Y.Qiao department of civil engineering, university of Akron, Akron, OH 44325-3905, USA department of civil engineering University of Akron Akron OH 44325-3905 United States

Due to the non-uniform nature of crack advance, when a cleavage front encounters a high-angle grain boundary, instead of simultaneous break-through along the whole boundary, the front transmission mode can be irregular, which results in a higher fracture resistance and a tortuous percolation behavior. In this paper, this phenomenon is studied quantitatively through the analysis on the work of separation and the change in strain energy for an Fe-3 wt pct Si alloy. The influences of the crystallographic misorientations, the break-through mode, the cleavage front profile, and the grain boundary properties are discussed in detail.

关键词： Fracture toughness Transgranular Iron-silicon alloy Irregular mode

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Effect of Cooling Rate on Morphology and Oxygen Permeability of Polypropylene

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 219-223页

作者： Wei Tian Raymond T. Whodhams(Material Science and engineering School, university of Science and Technology Beijing, Beijing 100083, China)(department of Chemical engineering and Applied Chemistry university of toronto, toronto M5S IA4, canada) Material Science and engineering School University of Science and Technology Beijing Beijing 100083 China department of Chemical engineering and Applied Chemistry University of Toronto Toronto Ont. M5S IA4 Canada

The influence of different cooling rates on the morphology and oxygen permeabilityr of polypropylene containing ferrocene has been investigated. The spherulitic crystalline size and structure, which can affect the oxygen permeability are dependent upon the heating temperature, annealing time and cooling rate. The modulus of the composite was measured b}' dynamic mechanical analysis.

关键词： polypropylene oxygen permeability cooling rate

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