资源类型

期刊论文 1684

会议视频 29

会议信息 2

年份

2024 2

2023 76

2022 127

2021 122

2020 93

2019 117

2018 99

2017 87

2016 81

2015 95

2014 85

2013 67

2012 84

2011 79

2010 75

2009 53

2008 77

2007 97

2006 37

2005 25

展开 ︾

关键词

风险分析 9

能源 7

可持续发展 5

分析 4

对策 4

影响因素 4

数值模拟 4

管理 4

隧道 4

ANSYS 3

农业科学 3

抗击疫情 3

数值分析 3

环境 3

营养健康 3

裂缝 3

2035年 2

BNLAS 2

COVID-19 2

展开 ︾

检索范围：

排序： 展示方式：

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 165-175 doi: 10.1007/s11709-018-0484-4

摘要： In this manuscript, we study fracture of prestressed cylindrical concrete pipes. Such concrete pipes play a major role in tunneling and underground engineering. The structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the reinforcement. This allows the method to capture important phenomena compared to a pure shell model of concrete. A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in tension. The model is validated through comparisons with experimental data.

关键词： cylindrical concrete structures     limit state analysis     3D fracture modelling     prestressed composite pipes     reinforced concrete     three-point bending test    

HTML PDF 收藏

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 446-455 doi: 10.1007/s11709-013-0227-5

摘要： An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented. The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity. Both smooth and rough base strip foundations were considered associated with different collapse patterns. Presence of the groundwater flow leads to a non-symmetric collapse pattern, i.e., a weak side and a strong side in two-sided collapse patterns, depending on the direction of the flow. It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence, a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词： foundation     bearing capacity     limit analysis     numerical computation     plasticity     seepage    

HTML PDF 收藏

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 378-387 doi: 10.1007/s11709-022-0808-2

摘要： This study presents stability analyses of layered soil slopes in unsaturated conditions and uses a limit equilibrium method to determine the factor of safety involving suction stress of unsaturated soil. One-dimensional steady infiltration and evaporation conditions are considered in the stability analyses. An example of a two-layered slope in clay and silt is selected to verify the used method by comparing with the results of other methods. Parametric analyses are conducted to explore the influences of the matric suction on the stability of layered soil slopes. The obtained results show that larger suction stress provided in unsaturated clay dominates the stability of the layered slopes. Therefore, the location and thickness of the clay layer have significant influences on slope stability. As the water level decreases, the factor of safety reduces and then increases gradually in most cases. Infiltration/evaporation can obviously affect the stability of unsaturated layered slopes, but their influences depend on the soil property and thickness of the lower soil layer.

关键词： slope stability     suction stress     unsaturated soil     layered slope     limit equilibrium    

HTML PDF 收藏

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

《结构与土木工程前沿（英文）》 2015年 第9卷 第4期   页码 478-490 doi: 10.1007/s11709-015-0317-7

摘要： This paper presents a simple and efficient approach for predicting the plastic limit loads in cracked plane-strain structures. We use two levels of mesh repartitioning for the finite element limit analysis. The master level handles an adaptive primal-mesh process through a dissipation-based indicator. The slave level performs the subdivision of each triangle into three sub-triangles and constitutes a dual mesh from a pair of two adjacent sub-triangles shared by common edges of the primal mesh. Applying a strain smoothing projection to the strain rates on the dual mesh, the incompressibility constraint and the flow rule constraint are imposed over the edge-based smoothing domains and everywhere in the problem domain. The limit analysis problem is recast into the compact form of a second-order cone programming (SOCP) for the purpose of exploiting interior-point solvers. The present method retains a low number of optimization variables. It offers a convenient way for designing and solving the large-scale optimization problems effectively. Several benchmark examples are given to show the simplicity and effectiveness of the present method.

关键词： cracked structure     limit analysis     von Mises criterion     edge-based strain smoothing     second-order cone programming     adaptive    

HTML PDF 收藏

capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound finite element limitanalysis

Mantu MAJUMDER, Debarghya CHAKRABORTY

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 537-551 doi: 10.1007/s11709-021-0708-x

摘要： Ensuring a safe foundation design in soft clay is always a challenging task to engineers. In the present study, the effectiveness of under-reamed piles in soft clay underlaid by stiff clay is numerically studied using the lower-bound finite element limit analysis (LB FELA). The bearing and uplift capacities of under-reamed piles are estimated through non-dimensional factors and , respectively. These factors increased remarkably and marginally compared to and of the piles without bulbs when the bulb is placed in stiff and soft clay, respectively. For a given ratio of undrained cohesion of stiff to soft clay ( / ), the factors and moderately increased with the increase in the length-to-shaft-diameter ratio ( / ) and adhesion factors in soft clay ( ) and stiff clay ( ). The variation of radial stress along the pile–soil interface, distribution of axial force in the under-reamed piles, and state of plastic shear failure in the soil are also studied under axial compression and tension. The results of this study are expected to be useful for the estimation of the bearing and uplift capacities of under-reamed piles in uniform clay and soft clay underlaid by stiff clay.

关键词： bearing capacity     uplift capacity     under-reamed pile     clay     limit analysis    

HTML PDF 收藏

Axial compression behavior of CFRP-confined rectangular concrete-filled stainless steel tube stub column

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1144-1159 doi: 10.1007/s11709-021-0762-4

摘要： The mechanical properties of CFRP-confined rectangular concrete-filled stainless steel tube (CFSST) stub columns under axial compression were experimentally studied. A total of 28 specimens (7 groups) were fabricated for the axial compression test to study the influences of length-to-width ratio, CFRP constraint coefficient, and the thickness of stainless steel tube on the axial compression behavior. The specimen failure modes, the stress development of stainless steel tube and CFRP wrap, and the load–strain ratio curves in the loading process were obtained. Meanwhile, the relationship between axial and transverse deformations of each specimen was analyzed through the typical relative load−strain ratio curves. A bearing capacity prediction method was proposed based on the twin-shear strength theory, combining the limit equilibrium state of the CFRP-confined CFSST stub column under axial compression. The prediction method was calibrated by the test data in this study and other literature. The results show that the prediction method is of high accuracy.

关键词： CFRP     rectangular CFSST stub column     bearing capacity     limit equilibrium state     twin-shear strength theory    

HTML PDF 收藏

Steady-state thermal-hydraulic analysis of SCWR assembly

LIU Xiaojing, CHENG Xu

《能源前沿（英文）》 2008年 第2卷 第4期   页码 475-478 doi: 10.1007/s11708-008-0093-3

摘要： Among the six gen-IV reactor concepts recommended by the gen-IV international forum (GIF), supercritical water-cooled reactor (SCWR), the only reactor with water as coolant, achieves a high thermal efficiency and, subsequently, has economic advantages over the existing reactors due to its high outlet temperature. A thermal-hydraulic analysis of the SCWR assembly is performed in this paper using the modified COBRA-IV code. Two approaches to reduce the hot channel factor are investigated: decreasing the moderator mass flow and increasing the thermal resistance between moderator channel and its adjacent sub-channels. It is shown that heat transfer deterioration cannot be avoided in SCWR fuel assembly. It is, therefore, highly required to calculate the cladding temperature accurately and to preserve the fuel rod cladding integrity under heat transfer deterioration conditions.

关键词： cladding temperature     assembly     temperature     coolant     resistance    

HTML PDF 收藏

Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

《能源前沿（英文）》 2015年 第9卷 第3期   页码 247-258 doi: 10.1007/s11708-015-0364-8

摘要： Over the last decade, India has started to concentrate earnestly on renewable energy. The Indian government, as well as different state governments, are adopting policy instruments such as feed in tariff, captive consumption, renewable purchase obligation and generation based incentive etc. aimed at renewable energy development. This paper evaluates the effectiveness of state level incentives for the development of wind energy in India. Fixed effect panel data modelling technique of econometric analysis is used to analyse the data of 26 Indian states in 11 years. The results show that feed in tariff and captive consumption are the significant predictors of wind energy development. However, renewable purchase obligation does not affect wind energy significantly.

关键词： India     wind energy development     state incentives     econometric analysis     panel data    

HTML PDF 收藏

Modeling and analysis of steady-state vibration induced by backlash in servo rotary table

Xiao YANG,Dun LU,Sanli LIU,Jun ZHANG,Wanhua ZHAO

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 43-47 doi: 10.1007/s11465-015-0327-0

摘要：

Backlash cannot be always avoided in mechanical systems because of wear or looseness. Steady-state vibration may be induced by backlash in closed loop feed drive systems. This paper presents a mathematical model of a servo rotary table, considering the effect of backlash. The accuracy of this model is verified by an experiment. The influences of the parameters, such as position controller gain, velocity controller gain, load and the magnitude of backlash, on steady-state vibration are discussed. The steady-state vibration amplitude increases with the position controller gain, load and the magnitude of backlash. The steady-state vibration frequency increases with the position controller gain and the velocity controller gain, while an increase in load leads to a decrease in the frequency.

关键词： backlash     servo rotary table     steady-state vibration    

HTML PDF 收藏

Modeling limit force capacities of high force to volume lead extrusion dampers

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 609-622 doi: 10.1007/s11709-021-0724-x

摘要： Lead extrusion dampers are supplemental energy-dissipation devices that are used to mitigate seismic structural damage. Small volumetric sizes and high force capacities define high-force-to-volume (HF2V) devices, which can absorb significant response energy without sacrificial damage. However, the design of such devices for specific force capacities has proven difficult based on the complexities of their internal reaction mechanisms, leading to the adoption of empirical approaches. This study developed upper- and lower-bound force capacity estimates from analytical mechanics based on direct and indirect metal extrusion for guiding design. The derived equations are strictly functions of HF2V device geometric parameters, lead material properties, and extrusion mechanics. The upper-bound estimates from direct and indirect extrusion are denoted as (FUB,1, FUB,2) and (FUB,3, FUB,4), respectively, and the lower-bound estimates are denoted as (FLB, FLB,1) based on the combination of extrusion and friction forces. The proposed models were validated by comparing the predicted bounds to experimental force capacity data from 15 experimental HF2V device tests. The experimental device forces all lie above the lower-bound estimates (FLB, FLB,1) and below the upper-bound estimates (FUB,1, FUB,2, FUB,4). Overall, the (FLB, FUB,2) pair provides wider bounds and the (FLB,1, FUB,4/FUB,1) pair provides narrower bounds. The (FLB,1, FUB,1) pair has a mean lower-bound gap of 36%, meaning the lower bound was 74% of the actual device force on average. The mean upper-bound gap was 33%. The bulge area and cylinder diameter of HF2V devices are key parameters affecting device forces. These relatively tight bounds provide useful mechanics-based predictive design guides for ensuring that device forces are within the targeted design range after manufacturing.

关键词： extrusion     lead dampers     upper and lower bound     analytical modelling     limit force    

HTML PDF 收藏

Setting up a heart rate alarm limit to decrease oculocardiac reflex during strabismus surgery in children

ZHANG Kangkang, GU Enhua, LU Junjie

《医学前沿（英文）》 2008年 第2卷 第3期   页码 295-297 doi: 10.1007/s11684-008-0056-4

摘要： The aim of this paper is to investigate a method which may decrease the incidence and severity of oculocardiac reflex (OCR) without drugs. One hundred and sixty children undergoing strabismus surgery were allocated to two groups using double-blind randomization. OCR was defined as a decrease of more than 10% from the baseline heart rate during operation. An alarm sounded and a lamp flashed as soon as OCR occurred in group I, and neither of the above happened in group II. OCR occurred (1.151 ± 0.858) times in group I and (2.287 ± 1.371) times in group II ( < 0.05). Heart rate decreased by (23 ± 19) bpm in group I and (35 ± 28) bpm in group II ( < 0.05). The duration of OCR in group I and group II was (4.36 ± 4.26)s and (7.62 ± 6.41)s, respectively ( < 0.05). The recovery time for group I and group II was (15.36 ± 13.28)s and (32.36 ± 19.57)s, respectively ( < 0.05). The numbers of times of interruption were 8 in group I (10%) and 26 in group II (32%) ( < 0.01). This method significantly decreased the incidence and severity of OCR during strabismus surgery in children.
HTML PDF 收藏

New model of load transfer function for pile analysis based on disturbed state model

LIU Qijian, YANG Linde, WU Jun

《结构与土木工程前沿（英文）》 2007年 第1卷 第4期   页码 443-447 doi: 10.1007/s11709-007-0060-9

摘要： Based on the disturbed state concept (DSC), a new model of load transfer function for pile analysis is established by the idea that the deformed material between pile and soil can be treated as a mixture of two constituent parts, which are in intact or critical state and assumed to obey random distribution. Starting from the homogenization theory of heterogeneous materials and statistics method, a parameter to describe the disturbance degree is proposed, and a formula to determine the parameter has been derived by using the plastic displacement of a pile as distribution variable. In the model, shear intensity of elements in an intact state are simulated by Duncan-Zhang model and that in a critical state by Mohr-Coulomb criterion. The model of this paper has few parameters, which can reflect the aspects of load transfer function, such as hardening, softening and the effects of confining pressure. The well agreement between the in-situ data and the predicted shows that the validity of the model herein. So the proposed model in this paper is easy to be used in engineering practice.

关键词： hardening     homogenization     displacement     engineering     Duncan-Zhang    

HTML PDF 收藏

有限元极限分析法发展及其在岩土工程中的应用

郑颖人,赵尚毅,邓楚键,刘明维,唐晓松,张黎明

《中国工程科学》 2006年 第8卷 第12期   页码 39-61

摘要：

有限元极限分析法兼有数值分析法与经典极限分析法两者的优点，特别适用于岩土工程的分析与设计。20世纪初，国内岩土工程界应用国际上通用程序，大力发展有限元极限分析法并拓宽其在岩土工程中的应用。在基本理论研究、提高计算精度、拓宽应用范围及工程实际应用等方面取得了很大成绩。重点介绍作者及其合作者的一些研究成果。主要包括岩土工程安全系数定义、方法原理、整体失稳判据、强度准则的推导、选用及提高计算精度等方面的研究。应用范围从二维扩大到三维，从均质土坡、土基扩大到有节理的岩质边坡与岩基，从稳定渗流扩大到不稳定渗流、从边坡与地基工程扩大到隧道、还用于寻找边（滑）坡中的多个潜在滑面，进行岩土与结构共同作用的支挡结构设计，计算机仿真地基承载板载荷试验等应用项目，以逐渐达到革新岩土工程设计方法的目的。

关键词： 极限分析法     有限元法     岩土工程     边坡     地基     隧道    

HTML PDF 收藏

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 566-583 doi: 10.1007/s11709-023-0905-x

摘要： The analysis of the bearing capacity of strip footings sited near an excavation is critical in geotechnics. In this study, the effects of the geometrical features of the excavation and the soil strength properties on the seismic bearing capacity of a strip footing resting on an excavation were evaluated using the lower and upper bounds of the finite element limit analysis method. The effects of the setback distance ratio (L/B), excavation height ratio (H/B), soil strength heterogeneity (kB/cu), and horizontal earthquake coefficient (kh) were analyzed. Design charts and tables were produced to clarify the relationship between the undrained seismic bearing capacity and the selected parameters.

关键词： excavation     finite element limit analysis     heterogeneous soil     strip footing     undrained bearing capacity    

HTML PDF 收藏

Modeling considerations in seismic assessment of RC bridges using state-of-practice structural analysis

Ricardo MONTEIRO, Miguel ARAÚJO, Raimundo DELGADO, Mário MARQUES

《结构与土木工程前沿（英文）》 2018年 第12卷 第1期   页码 109-124 doi: 10.1007/s11709-017-0389-7

摘要： The increasing awareness of the general society toward the seismic safety of structures has led to more restrictive performance requirements hence, many times, to the need of using new and more accurate methods of analysis of structures. Among these, nonlinear static procedures are becoming, evermore, the preferred choice of the majority of design codes, as an alternative to complete nonlinear time-history analysis for seismic design and assessment of structures. The many available software tools should therefore be evaluated and well understood, in order to be easily and soundly employed by the practitioners. The study presented herein intends to contribute to this need by providing further insight with respect to the use of commonly employed structural analysis software tools in nonlinear analysis of bridge structures. A comparison between different nonlinear modeling assumptions is presented, together with the comparison with real experimental results. Furthermore, alternative adaptive pushover procedures are proposed and applied to a case study bridge, based on a generic plastic hinge model. The adopted structural analysis program proved to be accurate, yielding reliable estimates, both in terms of local plastic hinge behavior and global structural behavior.

关键词： nonlinear analysis     pushover     RC bridges     structural modelling software    

HTML PDF 收藏

标题 作者 时间 类型 操作

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

期刊论文

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

期刊论文

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

期刊论文

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

期刊论文

capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound finite element limitanalysis

Mantu MAJUMDER, Debarghya CHAKRABORTY

期刊论文

Axial compression behavior of CFRP-confined rectangular concrete-filled stainless steel tube stub column

期刊论文

Steady-state thermal-hydraulic analysis of SCWR assembly

LIU Xiaojing, CHENG Xu

期刊论文

Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

期刊论文

Modeling and analysis of steady-state vibration induced by backlash in servo rotary table

Xiao YANG,Dun LU,Sanli LIU,Jun ZHANG,Wanhua ZHAO

期刊论文

Modeling limit force capacities of high force to volume lead extrusion dampers

期刊论文

Setting up a heart rate alarm limit to decrease oculocardiac reflex during strabismus surgery in children

ZHANG Kangkang, GU Enhua, LU Junjie

期刊论文

New model of load transfer function for pile analysis based on disturbed state model

LIU Qijian, YANG Linde, WU Jun

期刊论文

有限元极限分析法发展及其在岩土工程中的应用

郑颖人,赵尚毅,邓楚键,刘明维,唐晓松,张黎明

期刊论文

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

期刊论文

Modeling considerations in seismic assessment of RC bridges using state-of-practice structural analysis

Ricardo MONTEIRO, Miguel ARAÚJO, Raimundo DELGADO, Mário MARQUES

期刊论文