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Finite element simulation for elastic dislocation of the North-Tehran fault: The effects of geologiclayering and slip distribution for the segment located in Karaj

Pooya ZAKIAN; Hossein ASADI HAYEH

《结构与土木工程前沿(英文)》 2022年 第16卷 第4期   页码 533-549 doi: 10.1007/s11709-022-0802-8

摘要: The present study uses the finite element method for simulating the crustal deformation due to the dislocation of a segment of the North-Tehran fault located in the Karaj metropolis region. In this regard, a geological map of Karaj that includes the fault segment is utilized in order to create the geometry of finite element model. First, finite element analysis of homogeneous counterpart of the fault’s domain with two different sections was performed, and the results were compared to those of Okada’s analytical solutions. The fault was modeled with the existing heterogeneity of the domain having been considered. The influences of both uniform and non-uniform slip distributions were investigated. Furthermore, three levels of simplification for geometric creation of geological layers’ boundaries were defined in order to evaluate the effects of the geometric complexity of the geological layering on the displacement responses obtained with the finite element simulations. In addition to the assessment of slip distribution, layering complexity and heterogeneity, the results demonstrate both the capability and usefulness of the proposed models in the dislocation analysis for the Karaj segment of North-Tehran fault.

关键词: finite element method     fault dislocation     slip distribution     the North-Tehran fault     heterogeneity     geological layering    

Bridging finite element and deep learning: High-resolution stress distribution prediction in structural

Hamed BOLANDI; Xuyang LI; Talal SALEM; Vishnu Naresh BODDETI; Nizar LAJNEF

《结构与土木工程前沿(英文)》 2022年 第16卷 第11期   页码 1365-1377 doi: 10.1007/s11709-022-0882-5

摘要: Finite-element analysis (FEA) for structures has been broadly used to conduct stress analysis of various civil and mechanical engineering structures. Conventional methods, such as FEA, provide high fidelity results but require the solution of large linear systems that can be computationally intensive. Instead, Deep Learning (DL) techniques can generate results significantly faster than conventional run-time analysis. This can prove extremely valuable in real-time structural assessment applications. Our proposed method uses deep neural networks in the form of convolutional neural networks (CNN) to bypass the FEA and predict high-resolution stress distributions on loaded steel plates with variable loading and boundary conditions. The CNN was designed and trained to use the geometry, boundary conditions, and load as input to predict the stress contours. The proposed technique’s performance was compared to finite-element simulations using a partial differential equation (PDE) solver. The trained DL model can predict the stress distributions with a mean absolute error of 0.9% and an absolute peak error of 0.46% for the von Mises stress distribution. This study shows the feasibility and potential of using DL techniques to bypass FEA for stress analysis applications.

关键词: Deep Learning     finite element analysis     stress contours     structural components    

Analytical model and finite element computation of braking torque in electromagnetic retarder

Lezhi YE,Guangzhao YANG,Desheng LI

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 368-379 doi: 10.1007/s11465-014-0314-x

摘要:

An analytical model has been developed for analyzing the braking torque in electromagnetic retarder by flux tube and armature reaction method. The magnetic field distribution in air gap, the eddy current induced in the rotor and the braking torque are calculated by the developed model. Two-dimensional and three-dimensional finite element models for retarder have also been developed. Results from the analytical model are compared with those from finite element models. The validity of these three models is checked by the comparison of the theoretical predictions and the measurements from an experimental prototype. The influencing factors of braking torque have been studied.

关键词: electromagnetic retarder     magnetic field distribution     magnetic circuit     finite element method    

墙角火灾环境下钢构件温度分布及响应行为的实验研究

陈长坤,姚斌,杨昀,蔡昕,张和平,万玉田

《中国工程科学》 2005年 第7卷 第9期   页码 70-75

摘要:

利用ISO9705标准火灾实验系统,模拟墙角火灾环境,以薄壁方管钢梁为研究对象,对钢构件在热、力耦合作用下的行为进行实验研究。对火灾的热释放速率与室内温度场,钢构件及其表面气体的温度、构件在火灾作用下的挠度进行测量,分析真实火灾下钢构件温升及温度分布的特点与火灾发展对构件挠度的影响。研究结果表明钢构件在长向上存在着很大的温差,而构件的挠度变化也并不对称,这说明以往研究中往往假设钢构件在长向上温度一致并不恰当,这种非均匀温度场对构件的行为有着重要影响,它使得构件高温区部分更易发生局部屈服而失效,在相同规模的火灾环境下,与均匀温度场相比,这种墙角火灾所导致的非均匀温度场更不利于钢构件的安全。

关键词: ISO标准火灾实验系统     钢构件     墙角火     温度分布    

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 267-275 doi: 10.1007/s11709-010-0035-0

摘要: Discrete element method (DEM) was developed to simulate the corn-shaped particles flow in the hopper. The corn-shaped particle was described by four overlapping spheres. Contact force and gravity force were considered when establishing the model. In addition, flowing characteristic of particles in the hopper was studied. The effect of friction coefficient on the wall pressure, voidage and velocity distribution was analyzed. The results show that the discharge rate decreases with the friction coefficient increasing; and the “over-pressure” phenomenon occurs in the discharging process for two different friction coefficients. The voidage also increases as the friction coefficient increasing. And the velocity distribution is more uniformity and is closer to the mass flow with the friction coefficient deceasing.

关键词: discrete         element          method         (DEM)             non-spherical     voidage     pressure     velocity distribution     hopper    

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0861-y

摘要: Four types of S-rich particles are identified by SEM/FESEM-EDX With on-line observation, characteristics of S-rich particles are discovered Intensities of formation of S-rich particles are seasonally different Direct individual analysis using Scanning Electron Microscopy combined with online observation was conducted to examine the S-rich particles in PM of two typical polluted haze episodes in summer and winter from 2014 to 2015 in Beijing. Four major types of S-rich particles, including secondary CaSO particles (mainly observed in summer), S-rich mineral particles (SRM), S-rich water droplets (SRW) and (C, O, S)-rich particles (COS) were identified. We found the different typical morphologies and element distributions of S-rich particles and considered that (C, O, S)-rich particles had two major mixing states in different seasons. On the basis of the S-rich particles’ relative abundances, S concentrations and their relationships with PM as well as the seasonal comparison, we revealed that the S-participated formation degrees of SRM and SRW would enhance with increasing PM concentration. Moreover, C-rich matter and sulfate had seasonally different but significant impacts on the formation of COS.

关键词: S-rich particles     Morphology     Element distribution     Mixing state    

Method of internal 3D flow field numerical simulation for hydrodynamic torque converter

SHANG Tao, ZHAO Dingxuan, ZHANG Yuankun, GUO Xiangen, SHI Xiangzhong

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 86-90 doi: 10.1007/s11465-008-0012-7

摘要: To enhance the performance of a hydrodynamic torque converter and thoroughly understand the trait of inside flow, a numerical simulation method of internal 3D flow for the three-element centrifugal hydrodynamic torque converter was systematically researched and expatiated in this paper. First, the internal flow field of each impeller was calculated. The curves that illustrate the relationships between the pressure differences of the inlet and outlet versus flux were drawn. Second, the concurrent working point of each impeller was approximately estimated. Finally, a calculation was performed considering the influence on each impeller. The flow field of a working point was solved by multiple calculations and the actual working condition was gradually determined. The pressure and velocity distributions of the flow field were proposed. The performance parameters of the hydrodynamic torque converter were predicted. The calculation method, and the proposed pressure and velocity distribution of the flow field, have practical significance for the design and improvement of a hydrodynamic torque converter.

关键词: velocity distribution     calculation     numerical simulation     three-element centrifugal     converter    

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 236-242 doi: 10.1007/s11783-010-0218-8

摘要: Copper and zinc interaction on clearance from water and distribution in different tissues was investigated for the freshwater mussel, , under laboratory conditions. Clearance rate of Cu or Zn from water was highly dependent on exposure concentration. Interaction effect was most evident at 300 μg·L Cu exposure and depressed the Zn clearance rate significantly ( <0.05). However, the presence of 100 μg·L and 300 μg·L Zn hardly affected the Cu clearance rate. The 300 μg·L Cu presence enhanced Cu accumulation in each tissue most significantly ( <0.01), but caused Zn content to decrease in the gills by 62% ( <0.05), viscera by 49% ( <0.05) and foot by 31% ( <0.05), and increase in the mantle by 97% ( <0.05) and the muscles by 243% ( <0.05) for different Zn exposure treatments. The response of metal accumulation in various tissues of the test mussels indicated that Zn transferred from the gills, viscera and foot to the mantle and muscles might be one of the important characteristics of the Zn regulatory mechanism by leading to a narrow range of Zn concentration in the different tissues.

关键词: interaction     mussel     copper     zinc     clearance     distribution    

Acoustic analysis of lightweight auto-body based on finite element method and boundary element method

LIANG Xinhua, ZHU Ping, LIN Zhongqin, ZHANG Yan

《机械工程前沿(英文)》 2007年 第2卷 第1期   页码 99-103 doi: 10.1007/s11465-007-0017-7

摘要: A lightweight automotive prototype using alternative materials and gauge thickness is studied by a numerical method. The noise, vibration, and harshness (NVH) performance is the main target of this study. In the range of 1 150 Hz, the frequency response function (FRF) of the body structure is calculated by a finite element method (FEM) to get the dynamic behavior of the auto-body structure. The pressure response of the interior acoustic domain is solved by a boundary element method (BEM). To find the most contributing panel to the inner sound pressure, the panel acoustic contribution analysis (PACA) is performed. Finally, the most contributing panel is located and the resulting structural optimization is found to be more efficient.

关键词: harshness     automotive prototype     structural optimization     vibration     efficient    

Thermal buckling behavior of laminated composite plates: a finite-element study

Houdayfa OUNIS,Abdelouahab TATI,Adel BENCHABANE

《机械工程前沿(英文)》 2014年 第9卷 第1期   页码 41-49 doi: 10.1007/s11465-014-0284-z

摘要:

In this paper, the thermal buckling behavior of composite laminated plates under a uniform temperature distribution is studied. A finite element of four nodes and 32 degrees of freedom (DOF), previously developed for the bending and mechanical buckling of laminated composite plates, is extended to investigate the thermal buckling behavior of laminated composite plates. Based upon 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 implementation of the present finite element allowed the comparison of the numerical obtained results with results obtained from the literature: 1) with element of the same order, 2) the first order shear deformation theory, 3) the high order shear deformation theory and 4) the three-dimensional solution. It was found that the obtained results were very close to the reference results and the proposed element offers a good convergence speed. Furthermore, a parametrical study was also conducted to investigate the effect of the anisotropy of composite materials on the critical buckling temperature of laminated plates. The study showed that: 1) the critical buckling temperature generally decreases with the increasing of the modulus ratio EL/ET and thermal expansion ratio αT/αL, and 2) the boundary conditions and the orientation angles significantly affect the critical buckling temperature of laminated plates.

关键词: thermal buckling     laminated composite plates     anisotropy     critical buckling temperature     finite-element method     high precision rectangular Hermitian element    

Special Column on Multiscale Stochastic Finite Element Method

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 105-106 doi: 10.1007/s11709-015-0297-7

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 985-995 doi: 10.1007/s11705-021-2126-y

摘要: The high contents of nitrogen-containing organic compounds in biocrude obtained from hydrothermal liquefaction of microalgae are one of the most concerned issues on the applications and environment. In the project, Chlorella sp. and Spirulina sp. were selected as raw materials to investigate the influence of different reaction conditions (i.e., reaction temperature, residence time, solid loading rate) on the distribution of nitrogen in the oil phase and aqueous phase. Three main forms of nitrogen-containing organic compounds including nitrogen-heterocyclic compounds, amide, and amine were detected in biocrudes. The contents of nitrogen-heterocyclic compounds decreased with temperature while amide kept increasing. The effect of residence time on the components of nitrogen-containing organic compounds was similar with that of temperature. However, the influence of solid loading rate was insignificant. Moreover, it was also found that the differences of amino acids in the protein components in the two microalgae might affect the nitrogen distribution in products. For example, nitrogen in basic amino acids of Spirulina sp. preferred to go into the aqueous phase comparing with the nitrogen in neutral amino acids of Chlorella sp. In summary, a brief reaction map was proposed to describe the nitrogen pathway during microalgae hydrothermal liquefaction.

关键词: microalgae     hydrothermal liquefaction     biocrude     nitrogen distribution    

Comparison of indirect boundary element and finite element methods A case study: Shiraz-Esfahan railway

Amin MANOUCHEHRIAN, Mohammad Fatehi MARJI, Mohsen MOHEBBI

《结构与土木工程前沿(英文)》 2012年 第6卷 第4期   页码 385-392 doi: 10.1007/s11709-012-0173-7

摘要: Because of the high importance of transportation tunnels, most precise analyses of stress concentration and displacement around them are essential to provide safety of them as much as possible. Recently, various numerical methods such as finite element method (FEM), discrete element method (DEM), finite difference method (FDM) and boundary element method (BEM) have been used extremely in geosciences problems, but among these numerical methods, BEM has been used less than others because the computational algorithm is not so straightforward. This paper suggests the implementation of the indirect boundary element method (IBEM) as a formulation of BEM to analyze displacement around Shiraz-Esfahan railway tunnel in Zagros Mountains southwest of Iran. For this purpose, this tunnel has been modeled numerically using two-dimensional fictitious stress method (TWOFS) algorithm. To validate the results, they were compared with FEM results as a commonly used numerical method. Results of current theoretical study have shown that the presented approach using IBEM is reasonably accurate and can be used for analysis of displacement in geosciences problems. In rock mechanics, for problems with a low ratio of boundary surface to volume, FEM is not very well suited and may be cumbersome, but use of such a proposed IBEM approach can be particularly attractive.

关键词: indirect boundary element method     finite element method     displacement     tunnel     case study    

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

《能源前沿(英文)》 2011年 第5卷 第1期   页码 69-74 doi: 10.1007/s11708-010-0117-7

摘要: A coal-fired power unit frequently operates under unsteady conditions; thus, in order to acquire scientific energy analysis of the unit, thermodynamic analysis of a single-phase heated surface in a boiler under such conditions requires investigation. Processes are analyzed, and distributions of energy and exergy are qualitatively revealed. Models for energy analysis, entropy analysis, and exergy analysis of control volumes and irreversible heat transfer processes are established. Taking the low-temperature superheater of a 610 t/h-boiler as an example, the distribution of energy, entropy production, and exergy is depicted quantitatively, and the results are analyzed.

关键词: thermodynamic model     energy distribution     boiler     unsteady conditions    

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 341-351 doi: 10.1007/s11783-015-0776-z

摘要: The optimization of a water distribution network (WDN) is a highly nonlinear, multi-modal, and constrained combinatorial problem. Particle swarm optimization (PSO) has been shown to be a fast converging algorithm for WDN optimization. An improved estimation of distribution algorithm (EDA) using historic best positions to construct a sample space is hybridized with PSO both in sequential and in parallel to improve population diversity control and avoid premature convergence. Two water distribution network benchmark examples from the literature are adopted to evaluate the performance of the proposed hybrid algorithms. The experimental results indicate that the proposed algorithms achieved the literature record minimum (6.081 M$) for the small size Hanoi network. For the large size Balerma network, the parallel hybrid achieved a slightly lower minimum (1.921M?) than the current literature reported best minimum (1.923M?). The average number of evaluations needed to achieve the minimum is one order smaller than most existing algorithms. With a fixed, small number of evaluations, the sequential hybrid outperforms the parallel hybrid showing its capability for fast convergence. The fitness and diversity of the populations were tracked for the proposed algorithms. The track record suggests that constructing an EDA sample space with historic best positions can improve diversity control significantly. Parallel hybridization also helps to improve diversity control yet its effect is relatively less significant.

关键词: particle swarm optimization (PSO)     diversity control     estimation of distribution algorithm (EDA)     water distribution network (WDN)     premature convergence     hybrid strategy    

标题 作者 时间 类型 操作

Finite element simulation for elastic dislocation of the North-Tehran fault: The effects of geologiclayering and slip distribution for the segment located in Karaj

Pooya ZAKIAN; Hossein ASADI HAYEH

期刊论文

Bridging finite element and deep learning: High-resolution stress distribution prediction in structural

Hamed BOLANDI; Xuyang LI; Talal SALEM; Vishnu Naresh BODDETI; Nizar LAJNEF

期刊论文

Analytical model and finite element computation of braking torque in electromagnetic retarder

Lezhi YE,Guangzhao YANG,Desheng LI

期刊论文

墙角火灾环境下钢构件温度分布及响应行为的实验研究

陈长坤,姚斌,杨昀,蔡昕,张和平,万玉田

期刊论文

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

期刊论文

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

期刊论文

Method of internal 3D flow field numerical simulation for hydrodynamic torque converter

SHANG Tao, ZHAO Dingxuan, ZHANG Yuankun, GUO Xiangen, SHI Xiangzhong

期刊论文

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

期刊论文

Acoustic analysis of lightweight auto-body based on finite element method and boundary element method

LIANG Xinhua, ZHU Ping, LIN Zhongqin, ZHANG Yan

期刊论文

Thermal buckling behavior of laminated composite plates: a finite-element study

Houdayfa OUNIS,Abdelouahab TATI,Adel BENCHABANE

期刊论文

Special Column on Multiscale Stochastic Finite Element Method

期刊论文

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

期刊论文

Comparison of indirect boundary element and finite element methods A case study: Shiraz-Esfahan railway

Amin MANOUCHEHRIAN, Mohammad Fatehi MARJI, Mohsen MOHEBBI

期刊论文

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

期刊论文

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

期刊论文