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Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle

Nitesh Ganesh BHAT, B. Rajanarayan PRUSTY, Debashisha JENA

《能源前沿(英文)》 2017年 第11卷 第2期   页码 184-196 doi: 10.1007/s11708-017-0465-7

摘要: This paper applies a cumulant-based analytical method for probabilistic load flow (PLF) assessment in transmission and distribution systems. The uncertainties pertaining to photovoltaic generations and aggregate bus load powers are probabilistically modeled in the case of transmission systems. In the case of distribution systems, the uncertainties pertaining to plug-in hybrid electric vehicle and battery electric vehicle charging demands in residential community as well as charging stations are probabilistically modeled. The probability distributions of the result variables (bus voltages and branch power flows) pertaining to these inputs are accurately established. The multiple input correlation cases are incorporated. Simultaneously, the performance of the proposed method is demonstrated on a modified Ward-Hale 6-bus system and an IEEE 14-bus transmission system as well as on a modified IEEE 69-bus radial and an IEEE 33-bus mesh distribution system. The results of the proposed method are compared with that of Monte-Carlo simulation.

关键词: battery electric vehicle     extended cumulant method     photovoltaic generation     plug-in hybrid electric vehicle     probabilistic load flow    

Thermo-elastic extended meshfree method for fracture without crack tip enrichment

A. ASADPOUR

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 441-447 doi: 10.1007/s11709-015-0319-5

摘要: This is the first manuscript presenting an extended meshfree method for thermo- elastic fracture which does not exploit a crack tip enrichment. The crack is modeled by partition of unity enrichment of the displacement and temperature field. Only a step function is employed that facilitates the implementation. To ensure that crack tip is at the correct position, a Lagrange multiplier field ahead of the crack tip is introduced along a line. The Lagrange multiplier nodal parameters are discretised with the available meshfree functions. Two benchmark examples illustrate the efficiency of the method.

关键词: meshfree method     thermo-elasticity    

Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

《结构与土木工程前沿(英文)》 2010年 第4卷 第3期   页码 339-347 doi: 10.1007/s11709-010-0078-2

摘要: In this paper, a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method (X-FEM) for fatigue crack growth simulation. The proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical analysis. The X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element method. The basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial loadings. The small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth analysis. Model predictions are compared with available experimental observations for model validation.

关键词: small time scale model     extended finite element method (X-FEM)     crack growth     multiaxial    

Significant progress in solution of nonlinear equations at displacement of structure and heat transfer extended

M. R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 390-401 doi: 10.1007/s11465-014-0313-y

摘要:

In this paper, we aim to promote the capability of solving two complicated nonlinear differential equations: 1) Static analysis of the structure with variable cross section areas and materials with slope-deflection method; 2) the problem of one dimensional heat transfer with a logarithmic various surface A(x) and a logarithmic various heat generation G(x) with a simple and innovative approach entitled “Akbari-Ganji’s method” (AGM). Comparisons are made between AGM and numerical method, the results of which reveal that this method is very effective and simple and can be applied for other nonlinear problems. It is significant that there are some valuable advantages in this method and also most of the differential equations sets can be answered in this manner while in other methods there is no guarantee to obtain the good results up to now. Brief excellences of this method compared to other approaches are as follows: 1) Differential equations can be solved directly by this method; 2) without any dimensionless procedure, equation(s) can be solved; 3) it is not necessary to convert variables into new ones. According to the aforementioned assertions which are proved in this case study, the process of solving nonlinear equation(s) is very easy and convenient in comparison to other methods.

关键词: AGM     extended surface     heat transfer     slope-deflection method    

XFEM schemes for level set based structural optimization

Li LI, Michael Yu WANG, Peng WEI

《机械工程前沿(英文)》 2012年 第7卷 第4期   页码 335-356 doi: 10.1007/s11465-012-0351-2

摘要:

In this paper, some elegant extended finite element method (XFEM) schemes for level set method structural optimization are proposed. Firstly, two- dimension (2D) and three-dimension (3D) XFEM schemes with partition integral method are developed and numerical examples are employed to evaluate their accuracy, which indicate that an accurate analysis result can be obtained on the structural boundary. Furthermore, the methods for improving the computational accuracy and efficiency of XFEM are studied, which include the XFEM integral scheme without quadrature sub-cells and higher order element XFEM scheme. Numerical examples show that the XFEM scheme without quadrature sub-cells can yield similar accuracy of structural analysis while prominently reducing the time cost and that higher order XFEM elements can improve the computational accuracy of structural analysis in the boundary elements, but the time cost is increasing. Therefore, the balance of time cost between FE system scale and the order of element needs to be discussed. Finally, the reliability and advantages of the proposed XFEM schemes are illustrated with several 2D and 3D mean compliance minimization examples that are widely used in the recent literature of structural topology optimization. All numerical results demonstrate that the proposed XFEM is a promising structural analysis approach for structural optimization with the level set method.

关键词: structural optimization     level set method     extended finite element method (XFEM)     computational accuracy and efficiency    

An extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3) for free vibration analysis

M. H. NGUYEN-THOI,L. Le-ANH,V. Ho-HUU,H. Dang-TRUNG,T. NGUYEN-THOI

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 341-358 doi: 10.1007/s11709-015-0302-1

摘要: A cell-based smoothed discrete shear gap method (CS-FEM-DSG3) was recently proposed and proven to be robust for free vibration analyses of Reissner-Mindlin shell. The method improves significantly the accuracy of the solution due to softening effect of the cell-based strain smoothing technique. In addition, due to using only three-node triangular elements generated automatically, the CS-FEM-DSG3 can be applied flexibly for arbitrary complicated geometric domains. However so far, the CS-FEM-DSG3 has been only developed for analyzing intact structures without possessing internal cracks. The paper hence tries to extend the CS-FEM-DSG3 for free vibration analysis of cracked Reissner-Mindlin shells by integrating the original CS-FEM-DSG3 with discontinuous and crack−tip singular enrichment functions of the extended finite element method (XFEM) to give a so-called extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3). The accuracy and reliability of the novel XCS-FEM-DSG3 for free vibration analysis of cracked Reissner-Mindlin shells are investigated through solving three numerical examples and comparing with commercial software ANSYS.

关键词: cracked Reissner-Mindlin shell     free vibration analysis     cell-based smoothed discrete shear gap method (CS-FEM-DSG3)     extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3)     smoothed finite element methods (SFEM)    

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 796-811 doi: 10.1007/s11709-023-0922-9

摘要: Conventional geotechnical software limits the use of the strength reduction method (SRM) based on the Mohr–Coulomb failure criterion to analyze the slope safety factor (SF). The use of this constitutive model is impractical for predicting the behavior of all soil types. In the present study, an innovative numerical technique based on SRM was developed to determine SF using the finite element method and considering the extended Cam–clay constitutive model for clayey gravel soil as opposed to the Mohr–Coulomb model. In this regard, a novel user subroutine code was employed in ABAQUS to reduce the stabilizing forces to determine the failure surfaces and resist and drive shear stresses on a slope. After validating the proposed technique, it was employed to investigate the performance of terraced slopes in the context of a case study. The impacts of geometric parameters and different water table elevations on the SF were examined. The results indicated that an increase in the upper and lower slope heights led to a decrease in SF, and a slight increase in the horizontal offset led to an increase in the SF. Moreover, when the water table elevation was lower than the toe of the terraced slope, the SF increased because of the increase in the uplift force as a resistant component.

关键词: terraced slope     safety factor     finite element method     ABAQUS     extended Cam–clay    

Dynamic characteristics analysis of active constrained layer damping plate with various boundary conditions

Jing LU, Yu XIANG, Qiao NI

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 449-455 doi: 10.1007/s11465-011-0240-0

摘要:

Considering the direct and converse piezoelectric effect, expressions of piezoelectric membrane internal forces in the piezoelectric constrained layer were given. The control equations of the piezoelectric constrained layer and host plate were obtained in according with the thin plate theory. Based on the layer wised principle, the integrated first order differential equation of an active constrained layer damping (ACLD) plate was derived for the simply supported boundary condition. Then, this method was expanded to the ACLD plate with cantilever boundary condition by virtue of geometric analogy method. Employing the extended homogeneous capacity precision integration approach, a high precision semi-analytical method was proposed to analyze the dynamic characteristics of the ACLD plate with various boundary conditions. The comparison with the literature results has verified the accuracy and effectiveness of the present method.

关键词: active constrained layer damping (ACLD) plate     dynamic characteristics     semi-analytical method     extended homogeneous capacity precision integration approach    

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous media

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 914-936 doi: 10.1007/s11709-021-0750-8

摘要: Crack growth modeling has always been one of the major challenges in fracture mechanics. Among all numerical methods, the extended finite element method (XFEM) has recently attracted much attention due to its ability to estimate the discontinuous deformation field. However, XFEM modeling does not directly lead to reliable results, and choosing a strategy of implementation is inevitable, especially in porous media. In this study, two prevalent XFEM strategies are evaluated: a) applying reduced Young’s modulus to pores and b) using different partitions to the model and enriching each part individually. We mention the advantages and limitations of each strategy via both analytical and experimental validations. Finally, the crack growth is modeled in a natural porous media (Fontainebleau sandstone). Our investigations proved that although both strategies can identically predict the stress distribution in the sample, the first strategy simulates only the initial crack propagation, while the second strategy could model multiple cracks growths. Both strategies are reliable and highly accurate in calculating the stress intensity factor, but the second strategy can compute a more reliable reaction force. Experimental tests showed that the second strategy is a more accurate strategy in predicting the preferred crack growth path and determining the maximum strength of the sample.

关键词: numerical modeling     extended finite element method     porous media     crack growth     stress intensity factor    

Prony算法在步进频率雷达多目标检测中的建模研究

胡体玲,李兴国

《中国工程科学》 2008年 第10卷 第10期   页码 67-71

摘要:

步进频率信号是一种以增大信号带宽为代价来提高雷达距离分辨力的宽带信号。在步进频率雷达中,将接收的基带信号看作是包含目标信息的指数函数的线性组合;而Prony 算法是用指数函数的一组线性组合来描述等间距采样数据的数学模型。将扩充的Prony算法应用到步进频率体制的雷达中,可以得到更为精确的目标信息,并且可以克服直接采用IDFT合成高分辨距离像的一些缺点。相应的建模分析和实验仿真,说明了该算法的优越性。

关键词: 高分辨雷达     步进频率信号     扩展的Prony算法     多散射中心    

Efficient hydrothermal deoxygenation of methyl palmitate to diesel-like hydrocarbons on carbon encapsulated Ni–Sn intermetallic compounds with methanol as hydrogen donor

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 139-155 doi: 10.1007/s11705-022-2217-4

摘要: Porous carbon-encapsulated Ni and Ni–Sn intermetallic compound catalysts were prepared by the one-pot extended Stöber method followed by carbonization and tested for in-situ hydrothermal deoxygenation of methyl palmitate with methanol as the hydrogen donor. During the catalyst preparation, Sn doping reduces the size of carbon spheres, and the formation of Ni–Sn intermetallic compounds restrain the graphitization, contributing to larger pore volume and pore diameter. Consequently, a more facile mass transfer occurs in carbon-encapsulated Ni–Sn intermetallic compound catalysts than in carbon-encapsulated Ni catalysts. During the in-situ hydrothermal deoxygenation, the synergism between Ni and Sn favors palmitic acid hydrogenation to a highly reactive hexadecanal that easily either decarbonylate to n-pentadecane or is hydrogenated to hexadecanol. At high reaction temperature, hexadecanol undergoes dehydrogenation–decarbonylation, generating n-pentadecane. Also, the C–C bond hydrolysis and methanation are suppressed on Ni–Sn intermetallic compounds, favorable for increasing the carbon yield and reducing the H2 consumption. The n-pentadecane and n-hexadecane yields reached 88.1% and 92.8% on carbon-encapsulated Ni3Sn2 intermetallic compound at 330 °C. After washing and H2 reduction, the carbon-encapsulated Ni3Sn2 intermetallic compound remains stable during three recycling cycles. This is ascribed to the carbon confinement that effectively suppresses the sintering and loss of metal particles under harsh hydrothermal conditions.

关键词: extended Stöber method     carbon encapsulated Ni–Sn intermetallic compounds     confinement     in-situ hydrothermal deoxygenation     hydrogenation     decarbonylation    

Sensorless direct torque control for salient-pole PMSM based on extended Kalman filter fed by AC/DC/AC

F. BENCHABANE, A. TITAOUINE, O. BENNIS, K. YAHIA, D. TAIBI, A. GUETTAF

《能源前沿(英文)》 2012年 第6卷 第3期   页码 247-254 doi: 10.1007/s11708-012-0190-1

摘要: In this paper, a new sensorless interior permanent magnet synchronous motor (IPMSM) drives method with extended Kalman filter (EKF) for speed, rotor position and load torque estimation is proposed. The direct torque control (DTC) technique for permanent magnet synchronous motor (PMSM) is receiving increasing attention due to the important advantages of the low dependence on motor parameters when compared with other motor control techniques. The Kalman filter is an observer for linear and non-linear systems and is based on the stochastic intromission, in others words, noise. The PMSM is fed by an indirect power electronic converter which is controlled by a sliding mode technique. The simulation tests performed for different operating conditions have confirmed the robustness of the overall system; and it is shown that the sliding mode technique has successfully minimized the different harmonics introduced by the line converter.

关键词: direct torque control (DTC)     sensorless control     extended Kalman filter (EKF)     permanent magnet synchronous motor (PMSM)     boost-rectifier    

Uncertainty propagation analysis by an extended sparse grid technique

X. Y. JIA, C. JIANG, C. M. FU, B. Y. NI, C. S. WANG, M. H. PING

《机械工程前沿(英文)》 2019年 第14卷 第1期   页码 33-46 doi: 10.1007/s11465-018-0514-x

摘要: In this paper, an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle, aiming at improving the solving accuracy of the high-order moments and hence the fitting accuracy of the probability density function (PDF) of the system response. The proposed method incorporates the extended Gauss integration into the uncertainty propagation analysis. Moreover, assisted by the Rosenblatt transformation, the various types of extended integration points are transformed into the extended Gauss-Hermite integration points, which makes the method suitable for any type of continuous distribution. Subsequently, within the sparse grid numerical integration framework, the statistical moments of the system response are obtained based on the transformed points. Furthermore, based on the maximum entropy principle, the obtained first four-order statistical moments are used to fit the PDF of the system response. Finally, three numerical examples are investigated to demonstrate the effectiveness of the proposed method, which includes two mathematical problems with explicit expressions and an engineering application with a black-box model.

关键词: uncertainty propagation analysis     extended sparse grid     maximum entropy principle     extended Gauss integration     Rosenblatt transformation     high-order moments analysis    

An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memory

S. HASHEMI,H. AHMADIAN,S. MOHAMMADI

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 466-477 doi: 10.1007/s11709-015-0300-3

摘要: Thermo-mechanical coupling in shape memory alloys is a very complicated phenomenon. The heat generation/absorption during forward/reverse transformation can lead to temperature-dependent variation of its mechanical behavior in the forms of superelasticity and shape memory effect. However, unlike the usual assumption, slow loading rate cannot guarantee an isothermal process. A two-dimensional thermo-mechanically coupled algorithm is proposed based on the original model of Lagoudas to efficiently model both superelasticity and shape memory effects and the influence of various strain rates, aspect ratios and boundary conditions. To implement the coupled model into a finite element code, a numerical staggered algorithm is employed. A number of simulations are performed to verify the proposed approach with available experimental and numerical data and to assess its efficiency in solving complex SMA problems.

关键词: shape memory alloy     thermo-mechanical coupling     superplasticity     shape memory effect    

acid on natural magnetite and siderite: Evidence from sorption kinetics, sequential extraction and extended

《环境科学与工程前沿(英文)》 2022年 第16卷 第9期 doi: 10.1007/s11783-022-1547-2

摘要:

• DPAA sorption followed pseudo-secondary and intra-particle diffusion models.

关键词: Diphenylarsinic acid (DPAA)     Sorption     Magnetite     Siderite     Sequential extraction     EXAFS    

标题 作者 时间 类型 操作

Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle

Nitesh Ganesh BHAT, B. Rajanarayan PRUSTY, Debashisha JENA

期刊论文

Thermo-elastic extended meshfree method for fracture without crack tip enrichment

A. ASADPOUR

期刊论文

Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

期刊论文

Significant progress in solution of nonlinear equations at displacement of structure and heat transfer extended

M. R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI

期刊论文

XFEM schemes for level set based structural optimization

Li LI, Michael Yu WANG, Peng WEI

期刊论文

An extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3) for free vibration analysis

M. H. NGUYEN-THOI,L. Le-ANH,V. Ho-HUU,H. Dang-TRUNG,T. NGUYEN-THOI

期刊论文

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

期刊论文

Dynamic characteristics analysis of active constrained layer damping plate with various boundary conditions

Jing LU, Yu XIANG, Qiao NI

期刊论文

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous media

期刊论文

Prony算法在步进频率雷达多目标检测中的建模研究

胡体玲,李兴国

期刊论文

Efficient hydrothermal deoxygenation of methyl palmitate to diesel-like hydrocarbons on carbon encapsulated Ni–Sn intermetallic compounds with methanol as hydrogen donor

期刊论文

Sensorless direct torque control for salient-pole PMSM based on extended Kalman filter fed by AC/DC/AC

F. BENCHABANE, A. TITAOUINE, O. BENNIS, K. YAHIA, D. TAIBI, A. GUETTAF

期刊论文

Uncertainty propagation analysis by an extended sparse grid technique

X. Y. JIA, C. JIANG, C. M. FU, B. Y. NI, C. S. WANG, M. H. PING

期刊论文

An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memory

S. HASHEMI,H. AHMADIAN,S. MOHAMMADI

期刊论文

acid on natural magnetite and siderite: Evidence from sorption kinetics, sequential extraction and extended

期刊论文