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Explicit finite element method for calculation and analysis to the elasto-plastic dynamic response of

LI Liang, DU Xiuli, LI Liyun, ZHAO Chenggang

《结构与土木工程前沿（英文）》 2007年 第1卷 第4期   页码 436-442 doi: 10.1007/s11709-007-0059-2

摘要： In order to describe the elasto-plastic dynamic response of fluid-saturated porous media, the incremental elasto-plastic wave propagation equations of fluid-saturated porous media are developed by the fundamental theory of continuum mechanics and appointing to the characteristic of fluid-saturated porous media. Then, the space discretization of these equations is performed to get their Galerkin formula. At last, the time discretization of this formula is carried out with the integral method which consists of central difference method and Newmark constant average acceleration method to get the explicit time integral formula for solving the wave propagation equations of porous media. On the basis of the integral formula mentioned above, the time-domain explicit finite element method is developed for calculation and analysis of the elasto-plastic dynamic response of fluid-saturated porous media. In this method, the decoupling technique is adopted and it does not need to solve simultaneous linear equations in each time step, so the computational effort and memory requirement can be reduced considerably by using this method.

关键词： discretization     computational     calculation     integral     requirement    

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Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

《机械工程前沿（英文）》 2024年 第19卷 第3期 doi: 10.1007/s11465-024-0794-2

摘要： The failure types in gear systems vary, with typical ones mainly including pitting, cracking, wear, and broken teeth. Different modeling and stiffness calculation methods have been developed for various gear failure types. A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness (TVMS) of faulty gears resulting from the use of different methods. Specifically, a gear tooth is discretized into a large number of microelements expressed with a matrix, and unified models of typical gear failures are built by adjusting the values of the matrix microelements. The values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method (PEM), so the matrix-based failure model can be perfectly matched with PEM. Afterward, a unified method for TVMS is established. Modeling of healthy and faulty gears with pitting, wear, crack, and broken tooth is performed with the matrix equation, and the corresponding TVMS values are calculated by incorporating the matrix models with PEM. On the basis of the results, the mechanism of typical fault types that affect TVMS is analyzed, and the conclusions are verified through the finite element method. The developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.

关键词： gears     matrix equation     failure modeling     TVMS calculation     unified method    

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Application of an efficient stochastic calculation method on the seismic analysis of an isolated structure

Wei GUO, Zhiwu YU

《结构与土木工程前沿（英文）》 2012年 第6卷 第4期   页码 379-384 doi: 10.1007/s11709-012-0180-8

摘要： An isolated structure often possesses distinct non-proportional damping characteristics. However, traditional seismic calculation theory and methods are derived based on the assumption that damping is proportional. Based on this drawback, a new, more efficient stochastic calculation method, an improvement on the pseudo-excitation method, is introduced. This method is then applied to the seismic analysis of an isolated structure. By comparing it with the forced decoupling, matrix inversion and iteration methods, it is shown that the presented method can produce accurate results while increasing the efficiency of the stochastic analysis. Moreover, the calculation process of the seismic response of an isolated structure is convergent. Based on the results of the example presented in this paper, the given method is applicable to the seismic analysis of an isolated structure and can be utilized in practice.

关键词： isolated structure     stochastic response     non-proportional damping     efficient     accurate     pseudo-excitation method    

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The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 1015-1024 doi: 10.1007/s11783-014-0670-0

摘要： The Ecological Footprint (EF), a physical indicator to measure the extent of humanity’s use of natural resources, has gained much attention since it was first used by Wackernagel and Rees in 1996. In order to appraise land area types with different levels of productivity, they introduced the concept of an equivalence factor. This relates to the average primary biomass productivities of different types of land (i.e. arable land, pasture, forest, water/fishery, built-up land and fossil energy land) to the regional average primary biomass productivity of all land types in a given year. Hence, the equivalence factor is an important parameter in the EF model and it directly affects the reliability of all results. Thus, this article calculates equivalence factors on the national and provincial levels in China based on Net Primary Production (NPP) from MODIS 1 km data in 2008. Firstly, based on the Light Utility Efficiency and CASA model, the NPP of different biologically productive lands of China and of different provinces was calculated. Secondly, China’s equivalence factor for 6 land area types was calculated based on NPP: arable land and built-up land has an equivalence factor of 1.71, forest and fossil energy land has a factor of 1.41, pasture has a factor of 0.44 and water/fishery 0.35; Finally, the equivalence factor of 6 land area types in different provinces was also calculated. The NPP of each ecosystem type varies along with the equivalence factor in different provinces. However, the ranking of the equivalence factors in different provinces remain the same, with that of arable land being the largest, and the water/fishery being the smallest.

关键词： ecological footprint     equivalence factor     net primary production     biological capacity     land types    

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Unified calculation method and its application in determining the uniaxial mechanical properties of concrete

Faxing DING, Xiaoyong YING, Linchao ZHOU, Zhiwu YU

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 381-393 doi: 10.1007/s11709-011-0118-6

摘要： This paper presents a unified calculation method and its application in determining the uniaxial mechanical properties of concrete with concrete strengths ranging from 10 to 140 MPa. By analyzing a large collection of test results of the uniaxial mechanical properties of normal-strength, high-strength and super high-strength concrete in China and performing a regression analysis, unified calculation formulas for the mechanical indexes of concrete are proposed that can be applied to various grades of concrete for determining the size coefficient, uniaxial compressive strength, uniaxial tensile strength, elastic modulus, and strain at peak uniaxial compression and tension. Optimized mathematical equations for the nonlinear stress-strain relationship of concrete, including the ascending and descending branches under uniaxial stress, are also established. The elastic modulus is almost constant throughout the elastic stage for the ascending branches of the stress-strain relationship for concrete. The proposed stress-strain relationship of concrete was applied to the nonlinear finite element analysis of both a steel-concrete composite beam and a concrete-filled steel tubular stub column. The analytical results are in good agreement with the experiment results, indicating that the proposed stress-strain relationship of concrete is applicable. The achievements presented in this paper can be used as references for the design and nonlinear finite element analysis of concrete structures.

关键词： concrete     mechanical properties     stress-strain relationship     uniaxial stress     application    

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution     calculation method     pipe threaded connections     tension load    

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Calculation on phase diagrams of polyetherimide/

Ming TAN,Gaohong HE,Yan DAI,Rujie WANG,Wenhua SHI

《化学科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 312-319 doi: 10.1007/s11705-014-1434-x

摘要： The ternary phase diagrams of polyetherimide (PEI)/ , -dimethylacetamide (DMAc) with H O and BuOH as non-solvent were simulated using solubility parameter and Flory-Huggins theory. The phase diagrams show that 5.5% H O/BuOH system containing 5% BuOH and 0.5% H O, or 6.5% H O/BuOH system containing 6.2% BuOH and 0.3% H O is required to induce liquid-liquid demixing for 20 wt-% PEI/DMAc casting solution. Therefore, BuOH can enhance the phase separation of the PEI casting solution and hereby induce higher porosity of the membrane, and the diffusion of BuOH into the water coagulation bath causes larger pore size easily compared with DMAc. Our predictions that the membrane pure water flux first increases then decreases, and the rejection ratio of bovine serum albumin decreases with the increasing concentration of BuOH were validated by the experiments using the prepared membranes.

关键词： phase diagram     solubility parameter     interaction parameter     ultrafiltration     Flory-Huggins theory    

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Heuristic solution using decision tree model for enhanced XML schema matching of bridge structural calculation

Sang I. PARK, Sang-Ho LEE

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1403-1417 doi: 10.1007/s11709-020-0666-8

摘要： Research on the quality of data in a structural calculation document (SCD) is lacking, although the SCD of a bridge is used as an essential reference during the entire lifecycle of the facility. XML Schema matching enables qualitative improvement of the stored data. This study aimed to enhance the applicability of XML Schema matching, which improves the speed and quality of information stored in bridge SCDs. First, the authors proposed a method of reducing the computing time for the schema matching of bridge SCDs. The computing speed of schema matching was increased by 13 to 1800 times by reducing the checking process of the correlations. Second, the authors developed a heuristic solution for selecting the optimal weight factors used in the matching process to maintain a high accuracy by introducing a decision tree. The decision tree model was built using the content elements stored in the SCD, design companies, bridge types, and weight factors as input variables, and the matching accuracy as the target variable. The inverse-calculation method was applied to extract the weight factors from the decision tree model for high-accuracy schema matching results.

关键词： structural calculation document     bridge structure     XML Schema matching     weight factor     data mining     decision tree model    

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Aerodynamic design by jointly applying S2 flow surface calculation and modern optimization methods on

ZHAO Honglei, WANG Songtao, HAN Wanjin, FENG Guotai

《能源前沿（英文）》 2008年 第2卷 第1期   页码 93-98 doi: 10.1007/s11708-008-0007-4

摘要： A three-stage axial turbine was redesigned by jointly applying S2 flow surface direct problem calculation methods and multistage local optimization methods. A genetic algorithm and artificial neural network were jointly adopted during optimization. A three-dimensional viscosity Navier–Stokes equation solver was applied for flow computation. H-O-H-topology grid was adopted as computation grid, that is, an H-topology grid was adopted for inlet and outlet segment, whereas an O-topology grid was adopted for stator zone and rotor zone. Through the optimization design, the total efficiency increases 1.1%, thus indicating that the total performance is improved and the design objective is achieved.
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Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

《结构与土木工程前沿（英文）》 2009年 第3卷 第3期   页码 255-261 doi: 10.1007/s11709-009-0043-0

摘要： To improve the seismic performance of reinforced concrete core walls, reinforced concrete composite core walls with concealed steel truss were proposed and systemically investigated. Two 1/6 scale core wall specimens, including a normal reinforced concrete core wall and a reinforced concrete composite core wall with concealed steel truss, were designed. The experimental study on seismic performance under cyclic loading was carried out. The load-carrying capacity, stiffness, ductility, hysteretic behavior and energy dissipation of the core walls were discussed. The test results showed that the seismic performance of core walls is improved greatly by the concealed steel truss. The calculated results were found to agree well with the actual measured ones.

关键词： reinforced concrete     steel truss     core walls     seismic performance    

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Analyses of the seismic responses of soil layers with deep deposits

LOU Menglin, LI Yuchun, LI Nansheng

《结构与土木工程前沿（英文）》 2007年 第1卷 第2期   页码 188-193 doi: 10.1007/s11709-007-0021-3

摘要： Several typical problems in the seismic response analysis of soil layers with deep deposits have been studied according to the seismic response analysis of the soil layer in the Shanghai region. The problems include the effect of the inclination of the bedrock under the soil layer on the seismic responses of the soil layer, the rationality of the artificial horizontal bedrock boundary in the soil layer, and the effect of the wave velocity of the bedrock and dynamic characteristics of the soil media on the seismic responses of the soil layer. Some results are obtained by numerical analysis. In the seismic response analysis, the effect of angle of inclination of the rock surface under the soil layer can be neglected if the angle is not more than two degrees. A significant error will be introduced in the calculation when the artificial horizontal rock surface is assumed in the soil layer according to the shear velocity of the soil media. The elasticity of the solid rock has little influence on the seismic response of the deep soil layer. The field investigation on the soil dynamic property should be paid more attention to.

关键词： little influence     layer     calculation     Shanghai     dynamic    

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Thermodynamic performance experiment and cooling number calculation of a counter-flow spray humidifier

WANG Yuzhang, LI Yixing, WENG Shilie, WANG Yonghong

《能源前沿（英文）》 2008年 第2卷 第1期   页码 43-47 doi: 10.1007/s11708-008-0005-6

摘要： An experimental investigation of the thermodynamic performance of a counter-flow spray humidifier was conducted on the basis of theoretical analysis of the heat and mass transfer mechanism inside the humidifier. Critical parameters such as the temperature and relative humidity of air and the temperature of water at the inlet and outlet were measured. The influence of every measured parameter on the thermal performance of the humidifier was obtained under different experimental conditions. The cooling number, whose variation was also obtained, was calculated according to the measured data. The experimental results show that both the temperature and the temperature increment of outlet humid air and the temperature of outlet water increase with an increase of the water-gas ratio, whereas the cooling number decreases. Under all experimental conditions, the outlet humid air reaches or is close to the saturation level. The lower cooling number is favorable for the system, but it has an optimal value for a certain humidifier.

关键词： temperature increment     counter-flow     experimental investigation     temperature     water-gas    

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Calculation method on shape finding of self-anchored suspension bridge with spatial cables

Yan HAN, Zhengqing CHEN, Shidong LUO, Shankui YANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 165-172 doi: 10.1007/s11709-009-0021-6

摘要： Based on the spatial model, a reliable and accurate calculation method on the shape finding of self-anchored suspension bridge with spatial cables was studied in this paper. On the principle that the shape of the main cables between hangers is catenary, the iteration method of calculating the shapes of the spatial main cables under the load of hanger forces was deduced. The reasonable position of the saddle was determined according to the shape and the theoretical joint point of the main cables. The shapes of the main cables at completed cable stage were calculated based on the unchanging principle of the zero-stress lengths of the main cables. By using a numerical method combining with the finite element method, one self-anchored suspension bridge with spatial cables was analyzed. The zero-stress length of the main cables, the position of the saddle, and the pre-offsetting of the saddle of the self-anchored suspension bridge were given. The reasonable shapes of the main cables at bridge completion stage and completed cable stage were presented. The results show that the shape-finding calculation method is effective and reliable.

关键词： bridge engineering     self-anchored suspension bridges     special cables     shape-finding     calculation method    

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既有居住建筑节能改造外部性及其量化研究

赵琰,刘晓君

《中国工程科学》 2014年 第16卷 第10期   页码 100-105

摘要：

既有商品住宅节能改造具有一定程度的外部性，阻碍了节能改造的深入开展。通过分析节能改造外部性的产生原因和外部性表现，建立外部性测算方法，为外部性内部化，构建节能改造外部性偿还机制提供必要依据。采用经济学理论与方法对既有商品住宅节能改造外部性的产生和表现等进行了分析，在识别外部性供体与受体的基础上，提出了节能改造外部性的测算方法。通过案例分析论证了外部性测算方法的适用性。结果表明，应减轻或消除外部性对节能改造的影响，采取必要手段将节能改造外部性内部化，构建统一的节能改造外部性测算方法，建立节能改造外部性偿还与节能量交易机制。

关键词： 既有商品住宅     节能改造     外部性     测算    

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基于Voronoi区的GIS中方向关系的描述与计算

李成名

《中国工程科学》 2013年 第15卷 第5期   页码 25-29

摘要：

方向关系在地理信息系统（GIS）中占据着十分重要的地位，由于它的模糊性和依赖空间实体形状的特性，使得它的形式化描述和判断比较困难。本文在三角形模型（CDR）方法的基础上，利用最小矩形（MBR）四边的Voronoi多边形及其边界，形式化描述了方向关系，进而将方向关系分为主方向关系和次方向关系，并分别给出了两者利用MBR四边Voronoi多边形及其边界判断的算法。

关键词： 方向关系     Voronoi区     CDR     MBR    

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标题 作者 时间 类型 操作

Explicit finite element method for calculation and analysis to the elasto-plastic dynamic response of

LI Liang, DU Xiuli, LI Liyun, ZHAO Chenggang

期刊论文

Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

期刊论文

Application of an efficient stochastic calculation method on the seismic analysis of an isolated structure

Wei GUO, Zhiwu YU

期刊论文

The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

期刊论文

Unified calculation method and its application in determining the uniaxial mechanical properties of concrete

Faxing DING, Xiaoyong YING, Linchao ZHOU, Zhiwu YU

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Calculation on phase diagrams of polyetherimide/

Ming TAN,Gaohong HE,Yan DAI,Rujie WANG,Wenhua SHI

期刊论文

Heuristic solution using decision tree model for enhanced XML schema matching of bridge structural calculation

Sang I. PARK, Sang-Ho LEE

期刊论文

Aerodynamic design by jointly applying S2 flow surface calculation and modern optimization methods on

ZHAO Honglei, WANG Songtao, HAN Wanjin, FENG Guotai

期刊论文

Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

期刊论文

Analyses of the seismic responses of soil layers with deep deposits

LOU Menglin, LI Yuchun, LI Nansheng

期刊论文

Thermodynamic performance experiment and cooling number calculation of a counter-flow spray humidifier

WANG Yuzhang, LI Yixing, WENG Shilie, WANG Yonghong

期刊论文

Calculation method on shape finding of self-anchored suspension bridge with spatial cables

Yan HAN, Zhengqing CHEN, Shidong LUO, Shankui YANG

期刊论文

既有居住建筑节能改造外部性及其量化研究

赵琰,刘晓君

期刊论文

基于Voronoi区的GIS中方向关系的描述与计算

李成名

期刊论文