期刊文献+
任意字段
题名或关键词
题名
关键词
摘要
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息
共找到6,542篇文章
< 1 2 … 250 >
每页显示 20 50 100
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
显示方式：
Nonlinear mechanical behavior and shell-joint modeling method in rectangular pipe-jacking tunnel joints 认领 引用
1
作者 Zhengdong HUANG Youjun XU +3 位作者 Pengfei LI Chao ZHANG Yuhan SHAN Xu ZHANG 《ENGINEERING Structure and Civil Engineering》 SCIE EI CAS CSCD 2026年第4期804-827,共24页
Rectangular pipe-jacking tunnels are highly prone to longitudinal deformation under the influence of adjacent engineering activities,uneven foundation settlement,and changes in surface loads.These problems may lead to... Rectangular pipe-jacking tunnels are highly prone to longitudinal deformation under the influence of adjacent engineering activities,uneven foundation settlement,and changes in surface loads.These problems may lead to structural damage at the joints of rectangular pipe-jacking tunnels,potentially triggering engineering disasters.In response to these situations,this paper experimentally studies the effects of different foundation conditions and steel sleeve ring design parameters on their shear stiffness and rotational stiffness.It reveals three stages of joint failure:gap closure,steel sleeve ring stress,and deformation failure.A three-dimensional refined numerical simulation method is adopted to study the deformation and failure characteristics of joints under different foundation strengths and steel sleeve ring design parameters,analyze the mechanical performance of the joints of rectangular pipe-jacking tunnels,and verify the reliability of the experimental results.Based on the experimental and numerical simulation results,considering the nonlinear characteristics of the joints of rectangular pipe-jacking tunnels,a shell-joint theoretical model is constructed.Precise simulation is achieved through the combination of‘rotation+shear’dynamic elements,and the stiffness matrix at the joints and the calculation method of mechanical elements are derived.The shell-joint theoretical model is used to compare and verify the results of the joint tests of rectangular pipe-jacking tunnels,confirming the accuracy and practicality of the shell-joint theoretical model. 展开更多
关键词 rectangular pipe-jacking shell-joint mechanical model foundation stiffness longitudinal deformation
暂未订购 下载PDF
Numerical Investigation of Fluid Energy Evolution Under the Wave-Induced Gap Resonance Between Stationary Floating Rectangular Structures 认领 引用
2
作者 YU An-liang WANG Xin-yu +3 位作者 Domenico Davide MERINGOLO LIU Yong GONG Shao-dong WU Guo-xiang 《China Ocean Engineering》 SCIE EI CSCD 2026年第3期576-589,共14页
This study quantitatively examined the fluid energy evolution and dissipation process near narrow gaps formed between multiple floating rectangular structures under wave-induced gap resonance conditions.Given the limi... This study quantitatively examined the fluid energy evolution and dissipation process near narrow gaps formed between multiple floating rectangular structures under wave-induced gap resonance conditions.Given the limited understanding of gap resonance mechanisms through fluid energy analysis,a numerical wave flume based on theδ-LES-Smoothed Particle Hydrodynamics(SPH)approach was developed to investigate how incident wave and structural parameters influence the temporal evolution of fluid energy components.The findings reveal that for two floating boxes,the fluid energy dissipation within one wave period in the gap region between the boxes constitutes 81%of the total fluid energy dissipation in the fluid domain.This proportion remains consistent across varying incident wave heights under gap resonance conditions.The temporal distribution of fluid energy dissipation rate shows two peak values within one wave period,exhibiting significant waveform asymmetry.Additionally,in three-box configurations,the two narrow gap regions serve as primary zones of fluid energy dissipation,with energy dissipation patterns closely resembling those observed in the single gap region.Through comprehensive analysis of fluid energy evolution,this research advances the fundamental understanding of gap resonance mechanisms. 展开更多
关键词 multiple floating rectangular structures SPH method gap resonance wave energy evolution
暂未订购 下载PDF
Experimental and Numerical Evaluation of Elevated Rectangular Water Tank Frequencies Using Digital Image Correlation 认领 引用
3
作者 Askr M N Eraky A +1 位作者 Salama A Emad S 《Journal of Harbin Institute of Technology(New Series)》 CAS 2026年第2期56-67,共12页
Elevated,rectangular water tanks are an essential component of the water supply network and for emergency water storage.However,determining the dynamic response from seismic loads will require accurate estimates of th... Elevated,rectangular water tanks are an essential component of the water supply network and for emergency water storage.However,determining the dynamic response from seismic loads will require accurate estimates of their natural frequencies to help avoid damage or failure.Several numerical and analytical methodologies depend on assumptions that may not account for the complexity of fluid-structure interaction regarding rectangular geometries,indicating a strong need for solid experimental validation.This study pioneers the application of Digital Image Correlation(DIC),a non-contact optical technique,to measure the natural frequencies of a small-scale acrylic and Teflon tank,addressing this gap with a novel experimental approach.The method includes DIC using a high-speed camera,image analyzed by MATLAB,frequency analysis by Continuous Wavelet Transformation(CWT),and Fast Fourier Transformation(FFT);ANSYS finite element analysis,simplified models based on Eurocode and the Egyptian Code of Practice(ECP).Study results indicate that DIC is critical for attaining high accuracy,with maximum error differing by 2.92% for impulsive and 4.55%for convective frequencies from ANSYS and provides a better measure of dynamic response compared to contact-based measurements.Impulsive frequency decreased from 5.8724 Hz to 4.0085 Hz,and sloshing increased from 1.00 Hz to 1.84 Hz,as the water cover height varied from 0 cm to 9.8 cm.The Eurocode and ECP models describe acceptable errors of 7.36% and 9.21%,respectively.DIC showed higher accuracy,making it a useful tool for seismic design.This study improves the safety and reliability of designs for elevated water tanks in seismic regions with elevated seismic risk. 展开更多
关键词 fluid-structure interaction natural frequency rectangular tank elevated tank sloshing waves DIC
暂未订购 下载PDF
Gradient Descent-Based Prediction of Heat-Transmission Rate of Engine Oil-Based Hybrid Nanofluid over Trapezoidal and Rectangular Fins for Sustainable Energy Systems 认领 引用
4
作者 Maddina Dinesh Kumar S.U.Mamatha +2 位作者 Khalid Masood Nehad Ali Shah Se-Jin Yook 《Computer Modeling in Engineering & Sciences》 SCIE EI 2026年第1期627-660,共34页
Fluid dynamic research on rectangular and trapezoidal fins is aimed at increasing heat transfer by means of large surfaces.The trapezoidal cavity form is compared with its thermal and flow performance,and it is reveal... Fluid dynamic research on rectangular and trapezoidal fins is aimed at increasing heat transfer by means of large surfaces.The trapezoidal cavity form is compared with its thermal and flow performance,and it is revealed that trapezoidal fins tend to be more efficient,particularly when material optimization is critical.Motivated by the increasing need for sustainable energy management,this work analyses the thermal performance of inclined trapezoidal and rectangular porous fins utilising a unique hybrid nanofluid.The effectiveness of nanoparticles in a working fluid is primarily determined by their thermophysical properties;hence,optimising these properties can significantly improve overall performance.This study considers the dispersion of Graphene Oxide(GO)and Molybdenum Disulfide in the base fluid,engine oil.Temperature profiles are analysed by altering the radiative,porosity,wet porous,and angle of inclination parameters.Surface and contour plots are constructed by using the Lobatto IIIa Collocation Method with BVP5C solver in MATLAB and Gradient Descent Optimisation to predict the combined heat transfer rate.According to the study,fluid temperature consistently decreases when the angle of inclination,wet porous parameter,porosity parameter,and radiative parameter increase,suggesting significantly improved heat dissipation.The trapezoidal fin consistently exhibits a superior heat transfer mechanism than a rectangular fin.It is found that the trapezoidal fin transmits heat at a rate that is 0.05%higher than that of the rectangular fin.Validation of the present study is done through the comparison of previous studies.This research provides useful design insights for sophisticated engineering uses,including electrical cooling devices,heat exchangers,radiators,and solar heaters. 展开更多
关键词 Rectangular fin hybrid nanofluid trapezoidal fin angle of inclination gradient descent optimization Lobatto IIIa collocation method
暂未订购 下载PDF
Analytical solutions of vertical load on deep rectangular jacked pipe considering tunnelling-induced ground loss 认领 引用 被引量：4
5
作者 LI Jian-ye FANG Qian +4 位作者 LIU Xiang WANG Gan HUANG Jun DU Jian-ming ZHANG Zi-yi 《Journal of Central South University》 SCIE EI CAS CSCD 2025年第5期1855-1872,共18页
Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation... Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed. 展开更多
关键词 rectangular pipe jacking tunnel vertical load multi-layer parabolic soil arch model soil arching
暂未订购 下载PDF
Study on the effect of shape parameters and initiation points of rectangular high explosive on the spatial distribution of blast loads 认领 引用 被引量：2
6
作者 Longkui Chen Hongyu Zhao +2 位作者 Yongliang Zhang Shenghong Huang Chunhai Li 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2025年第3期102-120,共19页
Rectangular explosive charges are usually used in military or civilian explosive transportation and storage.The effects of shape parameters and detonation positions on the peak overpressure and maximum impulse of blas... Rectangular explosive charges are usually used in military or civilian explosive transportation and storage.The effects of shape parameters and detonation positions on the peak overpressure and maximum impulse of blasts lack comprehensive investigation,which is significant for the design of blast-resistant structures.In this paper,the side-length ratio of the rectangle,orientation,and detonation position of the charge are chosen as controlling parameters to investigate their influence on blast loads in the scaled distances of the gauges ranging from 0.63 to 10.54 m/kg1/3 with well validated 3D numerical simulations.The results show that there is a large difference in the near-field spatial distribution of the blast load of the rectangular charge;if the blast load of the rectangular charge is simply evaluated with the spherical charge,the maximum peak overpressure(maximum impulse)will be underestimated by a factor of 7.46(4.84).This must be taken seriously by blast-resistant structure designers.With the increase in the scaled distance,when the critical scaled distance is greater than 6.32(7.38)m/kg1/3,the influence of the charge shape on the maximum peak overpressure(maximum impulse)of the spatial blast load can be ignored.In general,the impact of detonation of the charge at the end on the maximum peak overpressure is greater compared with central detonation,but for the impact of the maximum impulse,it is necessary to pay attention to the side-length ratio of the rectangular charge and the specific detonation position on the end face.Furthermore,the structural response of steel plates placed at different azimuths under the blast load of a rectangular charge is preliminarily analyzed,and the results show that the deformation and energy of the plates are consistent with the distribution of the blast load.These analysis results provide a reference for the explosion protection design in near-field air explosions. 展开更多
关键词 Rectangular charge Side-length ratio Detonation Bridge wave Spherical equivalence
暂未订购 下载PDF
Failure mechanism and damage constitutive model of rectangular tunnels under water-rich condition 认领 引用
7
作者 Banquan Zeng Jianhang Chen +5 位作者 Wuyan Xu Xiaoyong An Shiji Wang Songsong Hu Kun Wang Yu Chen 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2025年第12期2245-2264,共20页
To investigate groundwater influence on stability and rockburst mechanism of deep hard-rock rectangular tunnels,water-immersed treatment and uniaxial compressive acoustic emission(AE)experiments were conducted on rect... To investigate groundwater influence on stability and rockburst mechanism of deep hard-rock rectangular tunnels,water-immersed treatment and uniaxial compressive acoustic emission(AE)experiments were conducted on rectangular tunnel specimens.Energy dissipation characteristics,AE evolution characteristics and damage evolution characteristics of rectangular tunnels were analysed under waterimmersed condition.Under water-immersed condition,tunnel specimens were quite sensitive to water.Average peak stress and average peak strain energy exhibited negative exponential decay with waterimmersed time.Among them,after 12 d of water immersion,average peak stress of specimens decreased by 28%.Average total strain energy decreased by 70%.Average elastic strain energy decreased by 71%and average dissipated strain energy decreased by 68%.After 62 d of water immersion,average peak stress of specimens decreased by 34%.Average total strain energy decreased by 78%.Average elastic strain energy decreased by 79%and average dissipated strain energy decreased by 75%.Water weakened bonding among mineral particles.Moreover,it undermined load-bearing capacity and diminished energystorage properties.Under high stress,massive releasable elastic strain energy stored in natural specimens within pre-peak stage may abruptly release after peak stress.This caused rapid crack development and connection in specimens.During accumulation and release of elastic strain energy,initial failure typically occurred at sidewalls.This failure location was not affected by water.Compared with natural specimens,Specimens immersed in water for 62 d had the lowest peak values of cumulative amplitude,cumulative AE energy and cumulative AE count.After 62 d of water immersion,peak values of cumulative amplitude,cumulative AE energy and cumulative AE count of specimens decreased by 84%,97%and 99%.Compared with AE damage model,fitting degree of energy damage model was higher.For natural specimens,fitting degree of energy damage model was 0.96.For specimens immersed in water for 12 d,fitting degree of energy damage model was 0.96.For specimens immersed in water for 62 d,fitting degree of energy damage model was 0.72.Therefore,an energy damage model had more remarkable applicability and reliability.By establishing dynamic mapping relationship between energy and damage in the model,accuracy of rockburst early warning has been significantly improved.This provided scientific basis for support structure design of rectangular tunnels and regulation of high strain energy. 展开更多
关键词 Rectangular tunnels Energy dissipation characteristics Evolution characteristics of AE signals Damage evolution characteristics Energy damage model
暂未订购 下载PDF
Flexural Nonlinear Natural Frequency Analysis of Rotational Functionally Graded Sandwich Rectangular Plates with Uniform and Inhomogeneous Pore Distributions in Thermal Environments 认领 引用
8
作者 Dazhi Zhang Yongqiang Li 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2025年第4期664-676,共13页
This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally... This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally graded sandwich rectangular plate in a thermal environment are derived using classical thin plate theory and Hamilton’s principle,considering geometric nonlinearity,temperature-dependent material properties,and power law distribution of components through the thickness.With cantilever boundary conditions,the flexural nonlinear differential equations of the rectangular sandwich plate are obtained via the Galerkin method.Since the natural vibration differential equations exhibit nonlinear characteristics,the multiscale method is employed to derive the expression for nonlinear natural frequency.An example analysis reveals how the natural frequency of a functionally graded sandwich rectangular plate varies with rotational speed and temperature.Results show that the nonlinear/linear frequency ratio increases with rotational angular velocity Ω and thickness-to-length ratio h/a,follows a cosine-like periodic pattern with the setting angle,and shows a sharp decrease followed by a rapid increase with increasing width-to-length ratio b/a.The derived analytical solutions for nonlinear frequency provide valuable insights for assessing the dynamic characteristics of functionally graded structures. 展开更多
关键词 Rectangular plate Sandwich Functionally graded material Nonlinear natural frequency Rotational motion
暂未订购 下载PDF
Experimental and Numerical Study on Flow and Heat Transfer Characteristics in Rectangular Channels with Leaf-Shaped Pin Fins 认领 引用 被引量：1
9
作者 Chao Zhang Runze Yan +2 位作者 Honghui Li Qingheng Tang Qinghai Zhao 《Frontiers in Heat and Mass Transfer》 EI CAS 2025年第2期421-440,共20页
The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinatio... The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinations of them were considered.The leaf-shaped design of the cooling pin fin enhances uniformity and synergy,effectively creating an optimized flow path that boosts cooling performance.Eight three-dimensional conjugate heat transfer models in staggered arrangement were developed using ANSYS-Fluent software.Aluminum6061material was used as the heat sinkmaterial and single-phase liquid water flowed through the rectangular channel where the Reynolds(Re)number varies from 40 to 100.Using the same boundary conditions as the software simulations,two leaf-shaped channels were printed to validate numerical models.Velocity field and temperature differences of the eight proposed leaf-shaped pin fins configurations were discussed by comparison with cylindrical pin fins.Based on the findings of this study,at a Reynolds number of 80,the Leaf B Staggered Array(LBSA)records a maximum temperature that is 0.72 K lower than that of the cylindrical pin fins arrangement.Additionally,the LBSA exhibits a reduction in the friction factor by approximately 33.3%relative to the circular pin fins array under the same Re.This implies that the design of LBSA has been optimized to provide better heat dissipation performance while maintaining lower energy consumption.Furthermore,the LBSA demonstrates the most favorable thermal-hydraulic performance index(TPI),which is 1.18 times higher than that of the circular pin fins arrangement at Re=80.The temperature reduction and friction factor reduction of the lobed channel is more pronounced than that of the conventional cooling channel,highlighting its potential to increase heat transfer efficiency and reduce energy consumption in practical applications. 展开更多
关键词 Heat transfer enhancement leaf-shaped pin fins rectangular channel single-phase heat transfer staggered arrangement
暂未订购 下载PDF
Thermo-Hydraulic Performances of Microchannel Heat Sinks with Different Types of Perforated Rectangular Blocks 认领 引用
10
作者 Heng Zhao Honghua Ma +4 位作者 Hui Liu Xiang Yan Huaqing Yu Yongjun Xiao Xiao Xiao 《Fluid Dynamics & Materials Processing》 EI 2025年第1期87-105,共19页
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex... The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400. 展开更多
关键词 Micro-channel heat sink(MCHS) perforated rectangular blocks thermal performance convection heat transfer
暂未订购 下载PDF
矩形光束照明的距离选通水下动态成像(特邀) 认领 引用 被引量：1
11
作者 魏自浩 王子豪 +2 位作者 董路 管帅 郭金家 《光学学报》 EI CAS CSCD 北大核心 2026年第12期233-246,共14页
针对水下远距离、大视场及动态成像的需求,设计并研制一套基于矩形光束照明的距离选通水下成像系统。该系统通过时间门控有效抑制水体后向散射,采用矩形光束提升能量利用率,并在紧凑型结构中内置扫描镜,可支持移动式与固定式两种扫描模... 针对水下远距离、大视场及动态成像的需求,设计并研制一套基于矩形光束照明的距离选通水下成像系统。该系统通过时间门控有效抑制水体后向散射,采用矩形光束提升能量利用率,并在紧凑型结构中内置扫描镜,可支持移动式与固定式两种扫描模式,以适应不同应用场景。实验结果表明,系统在25 m距离下可实现5 cm的分辨率,有效成像距离达到7.6个衰减长度,并验证了其在大视场快速扫描条件下的成像能力。同时,将元启发式算法应用于水下距离选通成像的动态校正,将姿态估计问题建模为全局优化任务,构建兼顾水下特征稀疏、高噪声与弱纹理特性的复合目标函数,提出一种基于粒子群优化的图像配准方法。该方法在目标轮廓重建与细节复原方面优于传统特征点方法与深度学习方法,有效提升系统在水下动态场景下的成像能力。 展开更多
关键词 水下成像 距离选通 矩形光束照明 元启发式算法 图像配准
暂未订购 下载PDF
矩形高层建筑顺风向脉动风荷载空间相关性 认领 引用 被引量：2
12
作者 袁家辉 陈水福 +1 位作者 夏俞超 刘奕 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2026年第3期772-783,共12页
为探讨建筑深宽比和来流湍流特性对矩形高层建筑顺风向脉动风荷载空间相关性的影响,对深宽比为1/9~9的矩形高层建筑在4种风场中进行了同步测压风洞试验。基于试验结果,分析建筑深宽比、湍流强度和湍流积分尺度对顺风向脉动风荷载竖向相... 为探讨建筑深宽比和来流湍流特性对矩形高层建筑顺风向脉动风荷载空间相关性的影响,对深宽比为1/9~9的矩形高层建筑在4种风场中进行了同步测压风洞试验。基于试验结果,分析建筑深宽比、湍流强度和湍流积分尺度对顺风向脉动风荷载竖向相关系数和相干函数的影响;通过非线性最小二乘法,拟合得到了适用于深宽比为1/9~9的矩形高层建筑竖向相关性数学模型。结果表明:顺风向脉动风荷载相关系数同时受到建筑深宽比和测点层高差影响,相关系数随测点层高差增大呈指数衰减;顺风向脉动相干函数随频率增大呈指数衰减,且衰减速率与高差和平均风速的比值大致成正比;对于不同深宽比建筑,湍流积分尺度和湍流强度对顺风向脉动风荷载相关性的影响不同;本文针对不同风场提出的矩形高层建筑顺风向脉动风荷载相关系数和相干函数公式和试验结果吻合良好,可为建筑结构设计及荷载规范修订提供参考。 展开更多
关键词 矩形高层建筑 脉动风荷载 空间相关性 风洞试验 深宽比
暂未订购 下载PDF
矩形顶管锁紧型接头抗震性能试验研究 认领 引用 被引量：1
13
作者 张朝 李鑫 +3 位作者 高柯 公衍德 魏嘉琛 许有俊 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2026年第3期1298-1309,共12页
由螺栓和F型承插接头构成的锁紧型接头在矩形顶管隧道工程中刚刚开始应用,目前对此类接头的抗震性能和地震破坏特征认识尚不清楚。为此,以包头市八一公园地下过街通道工程为研究背景,开展矩形顶管锁紧型接头模型拟静力试验,揭示螺栓连... 由螺栓和F型承插接头构成的锁紧型接头在矩形顶管隧道工程中刚刚开始应用,目前对此类接头的抗震性能和地震破坏特征认识尚不清楚。为此,以包头市八一公园地下过街通道工程为研究背景,开展矩形顶管锁紧型接头模型拟静力试验,揭示螺栓连接下矩形顶管锁紧型接头的地震破坏特征、破坏演化过程,探究其位移延性、耗能能力、刚度退化等抗震性能。研究结果表明:在低周反复荷载作用下,矩形顶管F型承插接头的破坏形式主要是插口脱出的变形破坏,而锁紧型接头的破坏形式为连接件被剪断的塑性破坏;锁紧型接头的破坏演化过程可归纳为弹性滑移(Ⅰ)、局部开裂延伸(Ⅱ)、结构失效(Ⅲ)3个阶段,呈现出典型的渐进式破坏特征,其腋角部位混凝土应变远大于其他位置,是核心受力部位,破坏最为严重。矩形顶管锁紧型接头滞回曲线的形状不饱满,呈现典型的反“S”型,接头延性及吸收地震能量的能力较差,但优于F型承插接头。F型承插接头的初始抗弯刚度远小于锁紧型接头,仅为锁紧型接头的3%。锁紧型接头在加载过程中刚度逐渐降低,其刚度退化呈非线性特征,Ⅰ阶段及Ⅱ阶段初期刚度退化明显,Ⅱ阶段腋角开裂后刚度退化逐渐变缓,Ⅱ阶段末刚度退化速率略有回升。至锁紧型接头破坏点时,正向、反向环线刚度分别降至初始刚度的32.1%和25.8%,接头仍具有一定剩余承载能力。研究结果可为优化矩形顶管隧道抗震韧性设计、保障矩形顶管隧道安全运营提供参考。 展开更多
关键词 隧道工程 矩形顶管 拟静力试验 抗震性能 破坏特征
暂未订购 下载PDF
一种大断面矩形顶管预制车站结构抗震性能研究 认领 引用 被引量：1
14
作者 吴永照 蒋首超 +5 位作者 朱其凯 阳文胜 刘树亚 姚浩宇 柳献 周胜阳 《工业建筑》 CAS 2026年第4期256-265,共10页
为研究大断面矩形顶管车站结构的抗震性能,设计开展了整体结构1∶5缩尺模型拟静力试验和纵缝接头足尺模型拟静力试验。试验结果表明:在整体结构缩尺模型拟静力试验中,结构出现裂缝时的水平力约为设计地震作用的7.5倍,当结构的顶部水平... 为研究大断面矩形顶管车站结构的抗震性能,设计开展了整体结构1∶5缩尺模型拟静力试验和纵缝接头足尺模型拟静力试验。试验结果表明:在整体结构缩尺模型拟静力试验中,结构出现裂缝时的水平力约为设计地震作用的7.5倍,当结构的顶部水平力达到设计地震作用的9倍时,结构骨架曲线基本仍处于弹性阶段;接头的滞回曲线形状均呈现梭形,滞回曲线峰值荷载后能保持一定的下降段,具备较好的变形能力,接头在达到峰值荷载后还有较强的耗能能力,抗震性能表现良好;该顶管车站预制结构和接头形式合理,抗震性能满足设计要求。 展开更多
关键词 大断面 矩形衬砌结构 整体结构 纵缝接头 抗震性能
暂未订购 下载PDF
砂土地层矩形顶管施工扰动模型试验 认领 引用 被引量：3
15
作者 李建业 许有俊 +5 位作者 张旭 房倩 马周伟 王拓 茹振华 刘翔 《中国公路学报》 EI CAS CSCD 北大核心 2026年第4期318-331,共14页
为系统研究矩形顶管隧道施工对砂土地层变形的扰动特征,研发了一套土压平衡矩形顶管模型试验平台。该平台由模型土箱、顶管模型机、注浆系统以及控制与监测系统等部分组成,能够精细化模拟土体切削、渣土排出、管节顶进与衬砌支护等关键... 为系统研究矩形顶管隧道施工对砂土地层变形的扰动特征,研发了一套土压平衡矩形顶管模型试验平台。该平台由模型土箱、顶管模型机、注浆系统以及控制与监测系统等部分组成,能够精细化模拟土体切削、渣土排出、管节顶进与衬砌支护等关键施工工艺。基于该试验平台,开展了砂土地层矩形顶管顶进施工的模型试验。试验过程中,系统监测了顶管顶进引起的地层变形及围岩压力变化,详细分析了矩形顶管施工诱发的地层变形特征和围岩压力演化规律。试验结果表明:矩形顶管隧道顶进施工引起的地表沉降呈现高斯分布特征,显著沉降区域主要集中在隧道中轴线两侧各1.0H(H为矩形顶管高度)范围内;地表沉降量和沉降槽宽度与地层损失率密切相关;地层损失率越大,地表最大沉降量显著增加,而沉降槽宽度则相应减小;拱顶土压力在施工过程中表现出“先减后稳”的演化规律,压力卸载区主要分布在隧道轴线两侧(0.5B+0.25H)范围内(B为矩形顶管宽度);此外,土体沉降的发展具有显著的时空演化特征;施工初期,近场区(距拱顶0.25H)土体率先发生快速沉降;随着顶管推进,远场区(距拱顶0.75H至1.25H)土体的沉降逐渐增大。研究成果可为砂土地层中矩形顶管的安全施工提供重要参考。 展开更多
关键词 隧道工程 扰动特征 模型试验 砂土地层 矩形顶管模型机 地层变形 土压力
暂未订购 下载PDF
不同风攻角4∶1矩形柱绕流大涡模拟 认领 引用 被引量：1
16
作者 董浩天 王亚松 +1 位作者 许庆 杜晓庆 《东南大学学报（自然科学版）》 EI CAS CSCD 北大核心 2026年第3期443-451,共9页
采用大涡模拟方法,在雷诺数为1.1×104和均匀流条件下,研究了宽高比4∶1矩形柱在风攻角α=0°~12°时的整体气动参数、表面压力分布、平均流场特性和瞬态流动特征,分析了矩形柱气动性能和流场特征的风攻角效应及其流动... 采用大涡模拟方法,在雷诺数为1.1×104和均匀流条件下,研究了宽高比4∶1矩形柱在风攻角α=0°~12°时的整体气动参数、表面压力分布、平均流场特性和瞬态流动特征,分析了矩形柱气动性能和流场特征的风攻角效应及其流动机理。在小风攻角α=0°~1°下,矩形柱绕流场呈上、下表面分离剪切层再附流态,流场对称性较高;平均和脉动气动力系数较小。在大风攻角α=3°~12°时,上表面保持分离剪切层再附,而下表面则未发生稳定的再附现象,在下侧面和尾流形成较大的回流区;随着攻角的增加,平均气动力系数绝对值总体呈现增大趋势,斯托罗哈数减小。在大攻角情况下,4∶1矩形柱受到更强和周期更长的横流向气动力作用,可能诱发涡激振动或改变涡振的风速锁定区间与振幅。 展开更多
关键词 桥梁抗风 矩形柱 风攻角 大涡模拟 气动性能 流场特性
暂未订购 下载PDF
矩形均布垂直荷载下三层地基竖向附加应力与位移解析方法 认领 引用 被引量：1
17
作者 梁瑶 倪睿思 +2 位作者 肖世国 贺钢 吴兵 《应用数学和力学》 CSCD 北大核心 2026年第2期158-177,共20页
对于实践中常见的三层地基的竖向附加应力与位移计算问题,现有理论方法尚不能进行合理且可便捷操作的解析.为了在理论计算方面解决此问题,基于弹性理论建立了三层地基的层状弹性半空间分析模型,通过中间变量转换,运用变量状态空间理论与... 对于实践中常见的三层地基的竖向附加应力与位移计算问题,现有理论方法尚不能进行合理且可便捷操作的解析.为了在理论计算方面解决此问题,基于弹性理论建立了三层地基的层状弹性半空间分析模型,通过中间变量转换,运用变量状态空间理论与Hankel积分变换方法,推导出了矩形均布垂直荷载下三层地基竖向附加应力与位移的紧凑解析解,并提出了避免数值溢出的高效率数值计算实现方法,包括地表沉降和地基内部竖向附加应力与位移的高精度数值积分边界处理方法.实例分析结果表明:该文方法与FLAC3D数值模拟结果吻合良好,与规范建议的有限深度地基模型的计算误差约为8%;对于各层差异明显的三层地基,当地表下一层土体厚度大于荷载宽度时,现行规范的均质地基方法计算的地基中附加应力误差较大;对由上而下依次为中-软-硬土层的地基,在土体深度与荷载宽度之比≤0.75时,三层地基理论的计算值小于传统均质地基方法的结果,反之,传统方法可能低估了地基中的附加应力.该文方法揭示出上两层土体不同厚度时,地基的中上部区域的附加应力差异较为显著,而增大最上面一层土体厚度,可明显提高地基中沿深度的应力扩散效率. 展开更多
关键词 多层地基 附加应力 矩形均布荷载 弹性半无限体 竖向位移
暂未订购 下载PDF
基于STNSRP扰动降尺度的太湖流域未来降雨预测 认领 引用 被引量：1
18
作者 蒋飞卿 朱易青 +5 位作者 朱超 陈宇飞 夏翔 牛智星 嵇海祥 王赠安 《水资源保护》 EI CAS CSCD 北大核心 2026年第1期173-183,共11页
针对当前统计降尺度方法在模拟极端降雨时的不足,将不确定性估计与降尺度结合,采用多站点Neyman-Scott矩形脉冲(STNSRP)模型,引入基于全球气候模式的扰动变化因子,开发了针对极端降雨的STNSRP扰动降尺度模型,据此预测了2026—2100年太... 针对当前统计降尺度方法在模拟极端降雨时的不足,将不确定性估计与降尺度结合,采用多站点Neyman-Scott矩形脉冲(STNSRP)模型,引入基于全球气候模式的扰动变化因子,开发了针对极端降雨的STNSRP扰动降尺度模型,据此预测了2026—2100年太湖流域的降雨。结果表明:STNSRP扰动降尺度模型采用随机点过程模拟降雨,有效模拟了降雨的极端特征,并提高了模拟精度,其模拟效果优于传统Delta法和Neyman-Scott矩形脉冲扰动降尺度模型;太湖流域2026—2100年年降水量呈增加趋势,增幅约为0.939 mm/a;汛期降水量大部分时间增加,且增加幅度随近期、中期、远期的时间推移而增大,而1月和10—11月的降水量将减少;西部山区未来降水量增幅大于东部平原区,浙西区大于湖西区;太湖流域降雨将趋于集中化,极端降雨强度和频率均有所增加;太湖流域未来水旱灾害防御中应着重加强防洪排涝工程体系建设,科学优化水库调度与水资源配置策略,健全极端天气下的应急响应机制。 展开更多
关键词 降雨预测 极端降雨 GCM降尺度 多站点Neyman-Scott矩形脉冲模型 扰动降尺度模型 太湖流域
暂未订购 下载PDF
矩形螺旋箍筋对矩形钢管混凝土柱抗火性能的提升作用 认领 引用
19
作者 仇培云 臧建波 王新祥 《华南理工大学学报（自然科学版）》 EI CAS CSCD 北大核心 2026年第2期123-132,共10页
内置箍筋约束能显著提升钢管混凝土(CFST)柱的抗火性能,且在无任何防火保护的情况下,仍可使构件满足对应耐火等级的设计要求,为结构防火设计和延长结构安全服役寿命提供了新途径。该文设计制作了3根足尺矩形CFST柱,对其进行标准火灾与... 内置箍筋约束能显著提升钢管混凝土(CFST)柱的抗火性能,且在无任何防火保护的情况下,仍可使构件满足对应耐火等级的设计要求,为结构防火设计和延长结构安全服役寿命提供了新途径。该文设计制作了3根足尺矩形CFST柱,对其进行标准火灾与荷载耦合作用下的明火试验,探究内置矩形螺旋箍筋对该类构件抗火性能的提升效果,并考察箍筋间距对其抗火性能的影响规律。基于材料现有的高温力学本构关系,建立了火灾作用下矩形螺旋箍筋约束矩形CFST柱的数值分析模型,揭示高温环境下箍筋约束核心混凝土对该类构件耐火极限的提升机理。研究结果表明:在总用钢量相同甚至略低的情况下,内置矩形螺旋箍筋可显著改善矩形CFST柱的耐火性能,耐火极限提升幅度高达104.1%;通过合理设计箍筋参数,该类轴压柱无需在钢管表面设置防火保护层,即可满足150 min的二级耐火等级要求;箍筋间距从40 mm增至80 mm时,对该类构件耐火性能的影响较小;所建数值模型可较好地预测内置矩形螺旋箍筋约束矩形CFST柱的耐火极限,但对构件不同受火时间下的变形预测精度欠佳。 展开更多
关键词 矩形螺旋箍筋 矩形CFST柱 耐火性能 箍筋间距 约束
暂未订购 下载PDF
A double-layer reflective metasurface with increased polarization independent channels through rotating array 认领 引用
20
作者 Bo YIN Xiaoliang LI Shubin WANG 《Optoelectronics Letters》 EI 2026年第6期337-343,共7页
The implementation of multifunctional metasurfaces through loading diodes has extremely high costs,while increasing the number of channels in the element through polarization multiplexing technology is limited.This pa... The implementation of multifunctional metasurfaces through loading diodes has extremely high costs,while increasing the number of channels in the element through polarization multiplexing technology is limited.This paper proposes a dual-band five-channel(DBFC)1-bit surface,which expands the polarization independent(PD)channels through rotating array.The polarization-independent metasurface element consists of three layers of metal,with the top layer comprising three rectangular patches oriented in the x-direction,the middle layer featuring a Jerusalem cross structure with accompanying resonators,and the bottom layer being a metal ground plane.The middle layer element can easily independently provide the required 1-bit reflection phases for two orthogonal polarizations in every frequency.The rectangular patches in the x-direction on the top layer do not contribute to the phase of y-polarization.By rotating the upper layer dielectric array 90°,the rectangular patches change to the y-direction.Under y-polarized illumination,the current distribution in the middle layer is shielded,providing a fifth set of polarization independent phases.The proposed 1-bit DBFC metasurface array has advantages in terms of structure and cost,while enhancing the utilization rate of the metasurface array.It has high application potential in microwave imaging,wireless power transmission,and other projects. 展开更多
关键词 Polarization independent channels Rotating array multifunctional metasurfaces loading diodes three rectangular patches Double layer reflective metasurface rotating arraythe polarization multiplexing technology
暂未订购 下载PDF
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
上一页 1 2 … 250 下一页 到第 页
在线咨询 使用帮助 返回顶部 意见反馈