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Cyber–Physical Power System (CPPS): A review on measures and optimization methods of system resilience

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 503-518 doi: 10.1007/s42524-021-0163-3

摘要: The Cyber–Physical Power System (CPPS) is one of the most critical infrastructure systems in a country because a stable and secure power supply is a key foundation for national and social development. In recent years, resilience has become a major topic in preventing and mitigating the risks caused by large-scale blackouts of CPPSs. Accordingly, the concept and significance of CPPS resilience are at first explained from the engineering perspective in this study. Then, a review of representative quantitative assessment measures of CPPS resilience applied in the existing literature is provided. On the basis of these assessment measures, the optimization methods of CPPS resilience are reviewed from three perspectives, which are mainly focused on the current research, namely, optimizing the recovery sequence of components, identifying and protecting critical nodes, and enhancing the coupling patterns between physical and cyber networks. The recent advances in modeling methods for cascading failures within the CPPS, which is the theoretical foundation for the resilience assessment and optimization research of CPPSs, are also presented. Lastly, the challenges and future research directions for resilience optimizing of CPPSs are discussed.

关键词: Cyber–Physical Power System     resilience assessment     resilience optimization     cascading failure modeling    

通过最小化边缘添加中的代数连接度来减少电网级联故障传播 Research Articles

Supaporn LONAPALAWONG1,颜姜哲2,李家雨3,叶德仕2,陈为1,汤涌4,黄彦浩4,王灿2

《信息与电子工程前沿(英文)》 2022年 第23卷 第3期   页码 382-397 doi: 10.1631/FITEE.2000596

摘要: 在各种情况下分析网络鲁棒性通常被认为是一个具有挑战性的问题。应对故障的鲁棒性是大型动态网络系统(如电力网、运输系统、通信系统和计算机网络)的基本特性之一。由于网络的多样性和复杂性,人们已提出许多拓扑特征以捕获系统特定属性。对于电网,通过拓扑设计提高网络结构鲁棒性是常见做法。然而,大多数现有方法集中于局部网络度量,例如节点连接度和边连接度,而非从全局视角看待电网中的级联传播。本文使用信息量大的全局度量代数连接度,因为它对谱图的全局连接度敏感。我们通过最小化代数连接度的增量以减少电网中的平均传播。提出一种基于拓扑的贪婪策略,以优化电网鲁棒性。为评估网络鲁棒性,使用MATCASC计算电网中级联故障中断的平均传播。实验结果表明,所提方法优于现有技术。

关键词: 网络鲁棒性;级联故障;平均传播;代数连接度;电网    

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 623-642 doi: 10.1007/s11709-021-0726-8

摘要: In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.

关键词: progressive failure     notched composite plate     Hashin failure criterion     macro mechanics approach     finite element method    

Surficial stability analysis of soil slope under seepage based on a novel failure mode

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 712-726 doi: 10.1007/s11709-021-0729-5

摘要: Normally, the edge effects of surficial landslides are not considered in the infinite slope method for surficial stability analysis of soil slopes. In this study, the limit stress state and discrimination equation of an infinite slope under saturated seepage flow were analyzed based on the Mohr-Coulomb strength criterion. Therefore, a novel failure mode involving three sliding zones (upper tension zone, middle shear sliding zone, and lower compression zone) was proposed. Accordingly, based on the limit equilibrium analysis, a semi-analytical framework considering the edge effect for the surficial stability of a soil slope under downslope seepage was established. Subsequently, the new failure mode was verified via a numerical finite element analysis based on the reduced strength theory with ABAQUS and some simplified methods using SLIDE software. The results obtained by the new failure mode agree well with those obtained by the numerical analysis and traditional simplified methods, and can be efficiently used to assess the surficial stability of soil slopes under rainwater seepage. Finally, an evaluation of the infinite slope method was performed using the semi-analytical method proposed in this study. The results show that the infinite slope tends to be conservative because the edge effect is neglected, particularly when the ratio of surficial slope length to depth is relatively small.

关键词: soil slope     seepage     surficial failure mode     stress state     edge effects    

Stability analysis of slopes with planar failure using variational calculus and numerical methods

Norly BELANDRIA, Roberto ÚCAR, Francisco M. LEÓN, Ferri HASSANI

《结构与土木工程前沿(英文)》 2020年 第14卷 第5期   页码 1262-1273 doi: 10.1007/s11709-020-0657-9

摘要: This study investigates the technique of variational calculus applied to estimate the slope stability considering the mechanism of planar failure. The critical plane failure surface should be determined because it theoretically indicates the most unfavorable plane to be considered when stabilizing a slope to rectify the instability generated by several statistically possible planes. This generates integrals that can be solved by numerical methods, such as the Newton Cotes and the finite differences methods. Additionally, a system of nonlinear equations is obtained and solved. The surface of the critical planar failure is determined by applying the condition of transversality in mobile boundaries, for which various examples are provided. The number of slices is varied in one of the examples, while the surface of the critical planar failure is determined in the others. Results are compared using analytical methods through axis rotations. All the results obtained by considering normal stress, safety factors, and critical planar failure are nearly the same; however, in this research, a study is carried out for “ ” number of slices using programming methods. Sub-routines are important because they can be applied in slopes with different geometry, surcharge, interstitial pressure, and pseudo-static load.

关键词: slopes stability     planar failure     variational calculus     numerical methods    

Improvement of the cascading closed loop cycle system

ZHANG Guoqiang, CAI Ruixian

《能源前沿(英文)》 2007年 第1卷 第3期   页码 341-346 doi: 10.1007/s11708-007-0051-5

摘要: Aspen Plus was used to simulate and get more information about the cascading closed loop cycle (CCLC) system [1–3]. Following evaluation of the variable temperature heat source (e.g. gas turbine flue gas) utilized by the CCLC, both qualitative and quantitive comparisons between the system and simple steam Rankine cycle, were made. The results indicate that CCLC has the advantage in recuperating exergy from flue gas, but it cannot sufficiently convert the recuperated exergy to useful work. To improve the utilization of low temperature flue gas heat, the properties and parameters of the working substance must match conditions of the low temperature heat source. A better cycle scheme and pressure distribution was proposed to raise the efficiency of the CCLC. In addition, the multifunction system concept was introduced to improve the performance of CCLC with solar energy.

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1222-1237 doi: 10.1007/s11709-021-0773-1

摘要: The influence of closed and open surface flaws on the stress distribution and failure in rock specimens is investigated. Heterogeneous finite element models are developed to simulate the compression tests on flawed rock specimens. The simulated specimens include those with closed flaws and those with open flaws on the surface. Systematic analyses are conducted to investigate the influences of the flaw inclination, friction coefficient and the confining stress on failure behavior. Numerical results show significant differences in the stress, displacement, and failure behavior of the closed and open flaws when they are subjected to pure compression; however, their behaviors under shear and tensile loads are similar. According to the results, when compression is the dominant mode of stress applied to the flaw surface, an open flaw may play a destressing role in the rock and relocate the stress concentration and failure zones. The presented results in this article suggest that failure at the rock surface may be managed in a favorable manner by fabricating open flaws on the rock surface. The insights gained from this research can be helpful in managing failure at the boundaries of rock structures.

关键词: surface flaw     heterogeneity     circular hole     numerical modeling     relative displacement    

Total stress rapid drawdown analysis of the Pilarcitos Dam failure using the finite element method

Daniel R. VANDENBERGE

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 115-123 doi: 10.1007/s11709-014-0249-7

摘要: Rapid drawdown is a critical design condition for the upstream or riverside slope of earth dams and levees. A new total stress rapid drawdown method based on finite element analysis is used to analyze the rapid drawdown failure that occurred at Pilarcitos Dam in 1969. Effective consolidation stresses in the slope prior to drawdown are determined using linear elastic finite element analysis. Undrained strengths from isotropically consolidated undrained (ICU) triaxial compression tests are related directly to the calculated consolidation stresses and assigned to the elements in the model by interpolation. Two different interpretations of the undrained strength envelope are examined. Strength reduction finite element analyses are used to evaluate stability of the dam. Back analysis suggests that undrained strengths from ICU tests must be reduced by 30% for use with this rapid drawdown method. The failure mechanism predicted for Pilarcitos Dam is sensitive to the relationship between undrained strength and consolidation stress.

关键词: rapid drawdown     finite element     total stress     slope stability    

Dynamic failure analysis on granite under uniaxial impact compressive load

ZHAI Yue, MA Guowei, HU Changming, ZHAO Junhai

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 253-260 doi: 10.1007/s11709-008-0042-6

摘要: High strain-rate uniaxial compressive loading tests were produced in the modified split Hopkinson pressure bar (SHPB) with pulse shaper on granite samples. It was shown that the failure of the granite cylinder was typical tensile splitting failure mode by sudden splitting parallel to the direction of uniaxial compressive loading at different strain rates. Besides, it was concluded that not only the strength of granite increased, but also the fragment size decreased and the fragment numbers increased with the increasing strain rate. To quantitatively analyze the failure phenomena, the numerical calculation based on a dynamic interacting sliding microcrack model was adopted to investigate the influence of microcrack with the different initial crack length, crack angle, crack space and friction coefficient on the macro-mechanical properties of granite under different strain rates. Accordingly, the strain-dependency of the compression strength and the fragmentation degree of granite was explained reasonably.

关键词: numerical calculation     coefficient     cylinder     splitting parallel     strain-dependency    

Experimental analysis on strength and failure modes of wood beam-column connections

Zhenhua HUANG,Sheldon Q SHI,Liping CAI

《结构与土木工程前沿(英文)》 2014年 第8卷 第3期   页码 260-269 doi: 10.1007/s11709-014-0261-y

摘要: This research experimentally examined the strength, failure modes, and behaviors of dowel-bearing and fiber-bearing wood beam-column connections and explored the effects of cyclic loading on the strength, failure modes, and behaviors of those connections. Base on limited numbers of exploratory laboratory tests (6 preliminary tests in total), the authors observed that the typical bolted connection (dowel-bearing type wood beam-column connection with fiber-bearing surfaces) showed good behavior (large peak moment) under the monotonic loads, and the tenon joint connection (fiber-bearing wood beam-column connection) showed good behavior under cyclic loads. The cyclic property of loading reduced the strength of the dowel-bearing type wood beam-column connections, but increased the strength of fiber-bearing type wood beam-column connections. More importantly, the authors identified a possible location of safety concern in current national design specifications (NDS) standards for the typical bolted connection (dowel-bearing connection with fiber bearing surface) under cyclic loading because the tested value was smaller than the NDS calculated value. But, because of the small amount of tests conducted, no final conclusion can be drawn based on those preliminary observations yet. A large number of repetitive laboratory tests should be conducted.

关键词: wood     connection     dowel-bearing     fiber-bearing    

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 281-294 doi: 10.1007/s11465-014-0307-9

摘要:

In this study, the stress concentration factors (SCF) in cross-and-angle-ply laminated composite plates as well as in isotropic plates with single circular holes subjected to uniaxial loading is studied. A quadrilateral finite element of four-node with 32 degrees of freedom at each node, previously developed for the bending and mechanical buckling of laminated composite plates, is used to evaluate the stress distribution in laminated composite plates with central circular holes. Based up on the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical results obtained by the present element compare favorably with those obtained by the analytic approaches published in literature. It is observed that the obtained results are very close to the reference results, which demonstrates the accuracy of the present element. Additionally, to determine the first ply failure (FPF) of laminated plate, several failure criterions are employed. Finally, to show the effect of ratio on the failure of plates, a number of figures are given for different fiber orientation angles.

关键词: laminated composite plates     stress concentration     geometric singularity     anisotropic effect    

Optimization of the mechanical performance and damage failure characteristics of laminated composites

《结构与土木工程前沿(英文)》   页码 1357-1369 doi: 10.1007/s11709-023-0996-4

摘要: In this study, the effect of fiber angle on the tensile load-bearing performance and damage failure characteristics of glass composite laminates was investigated experimentally, analytically, and numerically. The glass fabric in the laminate was perfectly aligned along the load direction (i.e., at 0°), offset at angles of 30° and 45°, or mixed in different directions (i.e., 0°/30° or 0°/45°). The composite laminates were fabricated using vacuum-assisted resin molding. The influence of fiber orientation angle on the mechanical properties and stiffness degradation of the laminates was studied via cyclic tensile strength tests. Furthermore, simulations have been conducted using finite element analysis and analytical approaches to evaluate the influence of fiber orientation on the mechanical performance of glass laminates. Experimental testing revealed that, although the composite laminates laid along the 0° direction exhibited the highest stiffness and strength, their structural performance deteriorated rapidly. We also determined that increasing the fiber offset angle (i.e., 30°) could optimize the mechanical properties and damage failure characteristics of glass laminates. The results of the numerical and analytical approaches demonstrated their ability to capture the mechanical behavior and damage failure modes of composite laminates with different fiber orientations, which may be used to prevent the catastrophic failures that occur in composite laminates.

关键词: fiber orientation     composite laminates     stiffness degradation     analytical approaches     finite element analysis    

Geotechnical forensic investigation of a slope failure on silty clay soil—A case study

Mohammad Abubakar NAVEED, Zulfiqar ALI, Abdul QADIR, Umar Naveed LATIF, Saad HAMID, Umar SARWAR

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 501-517 doi: 10.1007/s11709-020-0610-y

摘要: Qila Bala Hisar is one of the noteworthy places of Peshawar, Khyber Pakhtunkhwa. The fort was constructed on a filled ground during the 18th century and it was renovated several times by the occupants ever since. Recently, due to an earthquake of magnitude 7.3, the upper part of the south-western wall of the fort collapsed. The collapse of the wall was attributed to the failure of the retained slope. This research was undertaken to characterize the slope material, study causal factors of failure and evaluate remedial strategy. The investigation involved conventional field and laboratory testing and geophysical investigation using electrical resistivity technique to evaluate the nature of stratum. Also, X-ray Diffraction and Scanning Electron Microscopy was used to study the slope material at a molecular level to evaluate the existence of swelling potential. The analysis has shown that excessive seepage of water caused by the poor maintenance of runoff and sewage drains is the causal factor triggered by the seismic event. A remedial strategy involving soil nails, micro piles and improvement of the surface drainage is recommended.

关键词: forensic geotechnical investigation     slope failure     slope analysis     finite element method     numerical analysis     seismic loading     Qila Bala Hisar    

Application of metal magnetic memory test in failure analysis and safety evaluation of vessels

Yiliang ZHANG, Song YANG, Xuedong XU

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 40-48 doi: 10.1007/s11465-009-0003-3

摘要: Metal magnetic memory test (MMMT), which is a new subject in the field of nondestructive examination, can determine regions of stress concentration by testing the distribution of the magnetic field of metal structures so as to effectively diagnose premature defects. MMMT and other test methods are applied in the study to put a propylene purifier of a temperature-jump accident and a leaked ammonia vessel through safety evaluation. Results are as follows: The margin of safety declines after the purifier is overburnt; several stress concentrations are observed within the overburnt area and the level of stress concentration rises after one-month operation; and overpressure operation of the purifier must be strictly avoided and carefully monitored during later operation. Cracks are observed on the ammonia vessel after one year’s service. Extremely high residual stress is the primary cause of cracks. After four years in service, the residual stresses existing in the area of the base metal and weld zone are still greater than 0.5 , which results in numerous cracks due to stress corrosion. From the MMMT result of the ammonia vessel’s defects, it can be seen that the derivative of magnetic density (d p/d ) is an important reference variable. Within the 31 leakage points, 67.7% of them whose dHp/dx values are more than 10, and 96.8% of them whose dHp/dx values are more than 8.

关键词: Metal magnetic memory test (MMMT)     nondestructive testing (NDT)     residual stress     propylene purifier     ammonia vessel    

Lightweight design of an electric bus body structure with analytical target cascading

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0718-y

摘要: Lightweight designs of new-energy vehicles can reduce energy consumption, thereby improving driving mileage. In this study, a lightweight design of a newly developed multi-material electric bus body structure is examined in combination with analytical target cascading (ATC). By proposing an ATC-based two-level optimization strategy, the original lightweight design problem is decomposed into the system level and three subsystem levels. The system-level optimization model is related to mass minimization with all the structural modal frequency constraints, while each subsystem-level optimization model is related to the sub-structural performance objective with sub-structure mass constraints. To enhance the interaction between two-level systems, each subsystem-level objective is reformulated as a penalty-based function coordinated with the system-level objective. To guarantee the accuracy of the model-based analysis, a finite element model is validated through experimental modal test. A sequential quadratic programming algorithm is used to address the defined optimization problem for effective convergence. Compared with the initial design, the total mass is reduced by 49 kg, and the torsional stiffness is increased by 17.5%. In addition, the obtained design is also validated through strength analysis.

关键词: electric vehicle     body in white (BIW)     lightweight     analytical target cascading (ATC)    

标题 作者 时间 类型 操作

Cyber–Physical Power System (CPPS): A review on measures and optimization methods of system resilience

期刊论文

通过最小化边缘添加中的代数连接度来减少电网级联故障传播

Supaporn LONAPALAWONG1,颜姜哲2,李家雨3,叶德仕2,陈为1,汤涌4,黄彦浩4,王灿2

期刊论文

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

期刊论文

Surficial stability analysis of soil slope under seepage based on a novel failure mode

期刊论文

Stability analysis of slopes with planar failure using variational calculus and numerical methods

Norly BELANDRIA, Roberto ÚCAR, Francisco M. LEÓN, Ferri HASSANI

期刊论文

Improvement of the cascading closed loop cycle system

ZHANG Guoqiang, CAI Ruixian

期刊论文

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

期刊论文

Total stress rapid drawdown analysis of the Pilarcitos Dam failure using the finite element method

Daniel R. VANDENBERGE

期刊论文

Dynamic failure analysis on granite under uniaxial impact compressive load

ZHAI Yue, MA Guowei, HU Changming, ZHAO Junhai

期刊论文

Experimental analysis on strength and failure modes of wood beam-column connections

Zhenhua HUANG,Sheldon Q SHI,Liping CAI

期刊论文

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

期刊论文

Optimization of the mechanical performance and damage failure characteristics of laminated composites

期刊论文

Geotechnical forensic investigation of a slope failure on silty clay soil—A case study

Mohammad Abubakar NAVEED, Zulfiqar ALI, Abdul QADIR, Umar Naveed LATIF, Saad HAMID, Umar SARWAR

期刊论文

Application of metal magnetic memory test in failure analysis and safety evaluation of vessels

Yiliang ZHANG, Song YANG, Xuedong XU

期刊论文

Lightweight design of an electric bus body structure with analytical target cascading

期刊论文