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A dimensional analysis on asphalt binder fracture and fatigue cracking

Qian ZHAO, Zhoujing YE

《结构与土木工程前沿（英文）》 2018年 第12卷 第2期   页码 201-206 doi: 10.1007/s11709-017-0402-1

摘要： Fracture and fatigue cracking in asphalt binder are two of most serious problems for pavement engineers. In this paper, we present a new comprehensive approach, which consists both of dimensional analysis using Buckingham Theorem and -integral analysis based on classic fracture mechanics, to evaluate the fracture and fatigue on asphalt binder. It is discovered that the dimensional analysis could provide a new perspective to analyze the asphalt fracture and fatigue cracking mechanism.

关键词： Dimensional analysis     asphalt     fracture     fatigue cracking    

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Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

《结构与土木工程前沿（英文）》 2007年 第1卷 第2期   页码 217-221 doi: 10.1007/s11709-007-0026-y

摘要： It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simulations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by calculations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

关键词： ordinary two-dimensional     randomly     monolith     three-dimensional stability     different    

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Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0672-8

摘要： Surface roughness and thermal action are of remarkable importance in the lubrication performance of mechanical components, especially in extreme conditions. However, available studies mainly focus on the full-film lubrication conditions without considering temperature rise and real 3D surface roughness due to the complexity of surface topography and temperature characteristics. Moreover, studies on the interfacial thermal behaviors of 3D rough surface lubricated contact in an extended range of working conditions remain limited. In this paper, a deterministic mixed thermal elastohydrodynamic lubrication model considering real 3D surface roughness and thermal effects is proposed. In this model, pressure and temperature are coupled with each other, the computation of elastic deformation is accelerated through the discrete convolution and fast Fourier transform method, the temperature field is calculated with the column sweeping technique, and the semi-system method is introduced to improve convergence and numerical stability under severe conditions. The model is validated by comparing its results with available published numerical and experimental results. The thermal behaviors of the contact interface are studied in a wide range of working conditions. The influences of surface roughness and thermal effect on lubrication performance are revealed. The results show that the proposed model can be used as a powerful analysis tool for lubrication performance and temperature prediction in various heavy-load, high-speed lubricated components over a wide range of lubrication conditions.

关键词： thermal elastohydrodynamic lubrication     surface roughness effect     thermal effect     temperature characteristics     severe conditions    

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Three-dimensional electromagnetic analysis and design of permanent magnet retarder

Lezhi YE, Desheng LI, Bingfeng JIAO

《机械工程前沿（英文）》 2010年 第5卷 第4期   页码 438-441 doi: 10.1007/s11465-010-0111-0

摘要： An eddy current retarder for vehicles generates much heat when it works continuously, which leads to serious decline in braking torque. This paper proposes a novel permanent magnet retarder (PMR) for vehicles, whose cooling system connects with engine cooling-water. A three-dimensional finite element model is developed to model the electromagnetic behavior of a permanent magnet retarder under a constant speed. The magnetic field and eddy current field in PMR are numerically solved by a finite element method. By accounting for the nonlinear permeability of the rotor and the weakened effect in the magnetic field that is generated by the eddy current magnetic field, the calculation accuracy of air-gap magnetic field is enhanced. Experiment shows that the temperature of the retarder is less than 150°C, and the braking torque keeps the hard characteristics curve. The calculated air-gap magnetic flux density is fairly good agreement with the measured one.

关键词： auxiliary brake     permanent magnet retarder     water-cooling     finite element method    

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Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

《能源前沿（英文）》 2016年 第10卷 第4期   页码 424-440 doi: 10.1007/s11708-016-0423-9

摘要： This paper presents the simulation of major mechanical properties of a flux reversal generator (FRG) viz., computational fluid dynamic (CFD), thermal, and vibration. A three-dimensional finite element analysis (FEA) based CFD technique for finding the spread of pressure and air velocity in air regions of the FRG is described. The results of CFD are mainly obtained to fine tune the thermal analysis. Thus, in this focus, a flow analysis assisted thermal analysis is presented to predict the steady state temperature distribution inside FRG. The heat transfer coefficient of all the heat producing inner walls of the machine are evaluated from CFD analysis, which forms the main factor for the prediction of accurate heat distribution. The vibration analysis is illustrated. Major vibration sources such as mechanical, magnetic and applied loads are covered elaborately which consists of a 3D modal analysis to find the natural frequency of FRG, a 3D static stress analysis to predict the deformation of the stator, rotor and shaft for different speeds, and an unbalanced rotor harmonic analysis to find eccentricity of rotor to make sure that the vibration of the rotor is within the acceptable limits. Harmonic analysis such as sine sweep analysis to identify the range of speeds causing high vibrations and steady state vibration at a mode frequency of 1500 Hz is presented. The vibration analysis investigates the vibration of the FRG as a whole, which forms the contribution of this paper in the FRG literature.

关键词： flux reversal generator     air velocity     computation fluid dynamics     thermal analysis     vibration analysis     finite element analysis    

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Three-dimensional seismic response analysis of a concrete-faced rockfill dam on overburden layers

Dakuo FENG, Ga ZHANG, Jianmin ZHANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第2期   页码 258-266 doi: 10.1007/s11709-010-0031-4

摘要： Reasonable seismic response analysis of a high rockfill dam is of great engineering significance in guiding its design and ensuring its seismic safety during operation, especially of a concrete-faced rockfill dam (CFRD) on overburden layers. The three-dimensional seismic behavior of the Miaojiaba CFRD is simulated and analyzed by the finite element method (FEM). The results indicate that: 1) the amplification coefficient along the dam axis gradually increases with the altitude, and reaches maximum at the dam crest; 2) the vertical residual deformation mainly exhibits downwards and reaches maximum near the dam crest; 3) the earthquake significantly aggravates the deformation of peripheral joints; 4) the impounding condition and overburden characteristics have great effects on the dam’s seismic response.

关键词： concrete-faced rockfill dam (CFRD)     overburden layer     dynamic analysis     finite element method (FEM)    

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Application of a vertex chain operation algorithm on topological analysis of three-dimensional fractured

Zixin ZHANG, Jia WU, Xin HUANG

《结构与土木工程前沿（英文）》 2017年 第11卷 第2期   页码 187-208 doi: 10.1007/s11709-017-0391-0

摘要： Identifying the morphology of rock blocks is vital to accurate modelling of rock mass structures. This paper applies the concepts of directed edges and vertex chain operations which are typical for block tracing approach to block assembling approach to construct the structure of three-dimensional fractured rock masses. Polygon subtraction and union algorithms that rely merely on vertex chain operation are proposed, which allow a fast and convenient construction of complex faces/loops. Apart from its robustness in dealing with finite discontinuities and complex geometries, the advantages of the current methodology in tackling some challenging issues associated with the morphological analysis of rock blocks are addressed. In particular, the identification of complex blocks with interior voids such as cavity, pit and torus can be readily achieved based on the number and the type of loops. The improved morphology visualization approach can benefit the pre-processing stage when analyzing the stability of rock masses subject to various engineering impacts using the block theory and the discrete element method.

关键词： morphology     block assembling     vertex operation     discontinuities    

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Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 998-1011 doi: 10.1007/s11709-020-0621-8

摘要： Urban tunnels crossing faults are always at the risk of severe damages. In this paper, the effects of a reverse and a normal fault movement on a transversely crossing shallow shotcreted tunnel are investigated by 3D finite difference analysis. After verifying the accuracy of the numerical simulation predictions with the centrifuge physical model results, a parametric study is then conducted. That is, the effects of various parameters such as the sprayed concrete thickness, the geo-mechanical properties of soil, the tunnel depth, and the fault plane dip angle are studied on the displacements of the ground surface and the tunnel structure, and on the plastic strains of the soil mass around tunnel. The results of each case of reverse and normal faulting are independently discussed and then compared with each other. It is obtained that deeper tunnels show greater displacements for both types of faulting.

关键词： urban tunnel     sprayed concrete     reverse fault     normal fault     finite difference analysis    

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Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

《结构与土木工程前沿（英文）》   页码 915-934 doi: 10.1007/s11709-023-0907-8

摘要： A fictitious soil pile (FSP) model is developed to simulate the behavior of pipe piles with soil plugs undergoing high-strain dynamic impact loading. The developed model simulates the base soil with a fictitious hollow pile fully filled with a soil plug extending at a cone angle from the pile toe to the bedrock. The friction on the outside and inside of the pile walls is distinguished using different shaft models, and the propagation of stress waves in the base soil and soil plug is considered. The motions of the pile−soil system are solved by discretizing them into spring-mass model based on the finite difference method. Comparisons of the predictions of the proposed model and conventional numerical models, as well as measurements for pipe piles in field tests subjected to impact loading, validate the accuracy of the proposed model. A parametric analysis is conducted to illustrate the influence of the model parameters on the pile dynamic response. Finally, the effective length of the FSP is proposed to approximate the affected soil zone below the pipe pile toe, and some guidance is provided for the selection of the model parameters.

关键词： fictitious soil pile     soil plug     pipe piles     high-strain dynamic analysis     one-dimensional wave theory     pile dynamics    

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基于模糊集理论的二维线性鉴别分析新方法

郑宇杰,杨静宇,吴小俊,李勇智

《中国工程科学》 2007年 第9卷 第2期   页码 49-53

摘要：

二维线性鉴别分析（２DLDA）是一种直接基于矩阵的特征提取方法，跳过传统的基于Fisher鉴别准则 的线性鉴别分析方法中必须先将二维矩阵转化成一维矢量的过程，有效地提高了特征提取速度且避免了小样本问题，其识别率优于传统的Fisherface方法。结合模糊集理论，提出了一种新的２DLDA算法——模糊２DLDA （F１DLDA）算法。首先采用FKNN算法得到相应的样本分布信息，并按其对最后得到的特征向量所作的贡献融入 到特征抽取过程中，得到有效的样本特征向量集。实验表明，F２DLDA算法的性能优于传统的２DLDA算法和Fisherface算法。

关键词： 二维线性鉴别分析     模糊二维线性鉴别分析     模糊集理论     特征提取     模糊k近邻    

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Reliability assessment of three-dimensional bearing capacity of shallow foundation using fuzzy set theory

Rajarshi PRAMANIK, Dilip Kumar BAIDYA, Nirjhar DHANG

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 478-489 doi: 10.1007/s11709-021-0698-8

摘要： The aim of this study is to investigate the applicability of reliability theory on surface square/rectangular footing against bearing capacity failure using fuzzy set theory in conjunction with the finite element method. Soil is modeled as a three-dimensional spatially varying medium, where its parameters (cohesion, friction angle, unit weight, etc.) are considered as fuzzy variables that maintain some membership functions. Soil is idealized as an elastic-perfectly plastic material obeying the Mohr–Coulomb failure criterion, where both associated and non-associated flow rules are considered in estimating the ultimate bearing capacity of the footing. The spatial variability of the soil is incorporated for both isotropic and anisotropic fields, which are determined by the values of scales of fluctuation in both the horizontal and vertical directions. A new parameter namely, limiting applied pressure at zero failure probability is proposed, and it indirectly predicts the failure probability of the footing. The effect of the coefficient of variation of the friction angle of the soil on the probability of failure is analyzed, and it is observed that the effect is significant. Furthermore, the effect of the scale of fluctuation on the probability of failure is investigated, and the necessity for considering spatial variability in the reliability analysis is well proven.

关键词： finite element method     square footing     reliability analysis     fuzzy set theory     coefficient of variation     spatial variability    

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A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

《环境科学与工程前沿（英文）》 2012年 第6卷 第6期   页码 815-824 doi: 10.1007/s11783-011-0383-6

摘要： Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco-dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program (WASP, a modeling system introduced by the US Environmental Protection Agency) is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.

关键词： eutrophication     eco-dynamics     hydrodynamics     improved Water Quality Analysis Simulation Program (WASP) model     Baiyangdian Lake    

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Non linear modeling of three-dimensional reinforced and fiber concrete structures

Fatiha IGUETOULENE, Youcef BOUAFIA, Mohand Said KACHI

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 439-453 doi: 10.1007/s11709-017-0433-7

摘要： Under the effect of the ascending loading, the behavior of reinforced concrete structures is rather non linear. Research in industry and science aims to extend forward the use of non-linear calculation of fiber concrete for structural parts such as columns, veils and pious, as the fiber concrete is more ductile behavior then the classical concrete behavior. The formulation of the element has been established for modeling the nonlinear behavior of elastic structures in three dimensions, based on the displacement method. For the behavior of concrete and fiber concrete compressive and tensile strength (stress-strain) the uniaxial formulation is used. For steel bi-linear relationship is used. The approach is based on the discretization of the cross section trapezoidal tables. Forming the stiffness matrix of the section, the integral of the surface is calculated as the sum of the integrals on each of the cutting trapezoids. To integrate on the trapeze we have adopted the type of Simpson integration scheme.

关键词： numerical modeling     column and beam     nonlinear analysis     fibers     pious     reinforcement     3D formulation     response load-deflection    

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深层搅拌桩墙围护结构裂缝成因探讨

高文华,王祥秋,陈秋南,张志敏

《中国工程科学》 2005年 第7卷 第12期   页码 88-91

摘要：

针对基坑支护中深层搅拌桩墙围护结构出现的开裂，采用Mindlin厚板理论对其受力与变形性状进行弹塑性分析，建立了墙体的厚板力学模型和三维有限元分析模型，并编制了有限元分析程序；基于墙体受到纵向弯矩、横向弯矩和扭矩的综合作用，提出采用等效弯矩法评价墙体的综合抗弯性能；利用所编制的程序，获得了某基坑深层搅拌桩墙围护结构墙体水平位移和等效弯矩的空间分布规律；计算结果表明，墙体东侧环球广场横向支撑附加力的作用是使墙体形成破裂面的主要原因。

关键词： 裂缝     深层搅拌桩墙     厚板     等效弯矩     三维有限元    

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Numerical analysis of rotating stall characteristics in vaneless diffuser with large width-radius ratio

GAO Chuang, GU Chuangang, WANG Tong, DAI Zhengyuan

《能源前沿（英文）》 2008年 第2卷 第4期   页码 457-460 doi: 10.1007/s11708-008-0071-9

摘要： A two-dimensional model, where the influence of wall boundary layers is neglected and inlet jet-wake velocity patterns are prescribed, was applied to simulate one vaneless diffuser with a large width-radius ratio. The impact of diffuser length, impeller blade number, etc. on the rotating stall was analyzed. Computational results show that a different mechanism does exist for diffusers with large width-radius ratios. Comparison with related conclusions and references is supportive of the model.

关键词： Comparison     Computational     two-dimensional     influence     different mechanism    

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标题 作者 时间 类型 操作

A dimensional analysis on asphalt binder fracture and fatigue cracking

Qian ZHAO, Zhoujing YE

期刊论文

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

期刊论文

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

期刊论文

Three-dimensional electromagnetic analysis and design of permanent magnet retarder

Lezhi YE, Desheng LI, Bingfeng JIAO

期刊论文

Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

期刊论文

Three-dimensional seismic response analysis of a concrete-faced rockfill dam on overburden layers

Dakuo FENG, Ga ZHANG, Jianmin ZHANG,

期刊论文

Application of a vertex chain operation algorithm on topological analysis of three-dimensional fractured

Zixin ZHANG, Jia WU, Xin HUANG

期刊论文

Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

期刊论文

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

期刊论文

基于模糊集理论的二维线性鉴别分析新方法

郑宇杰,杨静宇,吴小俊,李勇智

期刊论文

Reliability assessment of three-dimensional bearing capacity of shallow foundation using fuzzy set theory

Rajarshi PRAMANIK, Dilip Kumar BAIDYA, Nirjhar DHANG

期刊论文

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

期刊论文

Non linear modeling of three-dimensional reinforced and fiber concrete structures

Fatiha IGUETOULENE, Youcef BOUAFIA, Mohand Said KACHI

期刊论文

深层搅拌桩墙围护结构裂缝成因探讨

高文华,王祥秋,陈秋南,张志敏

期刊论文

Numerical analysis of rotating stall characteristics in vaneless diffuser with large width-radius ratio

GAO Chuang, GU Chuangang, WANG Tong, DAI Zhengyuan

期刊论文