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Anisotropy of multi-layered structure with sliding and bonded interlayer conditions

Lingyun YOU, Kezhen YAN, Jianhong MAN, Nengyuan LIU

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 632-645 doi: 10.1007/s11709-020-0617-4

摘要: A better understanding of the mechanical behavior of the multi-layered structure under external loading is the most important item for the structural design and the risk assessment. The objective of this study are to propose and develop an analytical solution for the mechanical behaviors of multi-layered structure generated by axisymmetric loading, and to investigate the impact of anisotropic layers and interlayer conditions on the multi-layered structure. To reach these objectives, first, according to the governing equations, the analytical solution for a single layer was formulated by adopting the spatial Hankel transform. Then the global matrix technique is applied to achieve the analytical solution of multi-layered structure in Hankel domain. The sliding and bonded interlayer conditions were considered in this process. Finally, the numerical inversion of integral transform was used to solve the components of displacement and stress in real domain. Gauss-Legendre quadrature is a key scheme in the numerical inversion process. Moreover, following by the verification of the proposed analytical solution, one typical three-layered flexible pavement was applied as the computing carrier of numerical analysis for the multi-layered structure. The results have shown that the anisotropic layers and the interlayer conditions significantly affect the mechanical behaviors of the proposed structure.

关键词: multi-layered structure     Hankel transformation     anisotropic     transversely isotropic     interlayer condition     Gauss-Legendre quadrature    

Quantification of seepage in a multi-layered disconnected river-aquifer system

Jiang LI, Haizhu HU, Xiaomin MAO, Yi LIU

《农业科学与工程前沿(英文)》 2017年 第4卷 第2期   页码 237-245 doi: 10.15302/J-FASE-2017135

摘要: Quantification of seepage in disconnected river-aquifer systems is significant for local water management and groundwater pollution control, especially in areas with water shortage or contamination. The vadose zone under riverbeds usually exhibits a multi-layered structure, particularly when paved with low permeability liners. To evaluate the impact of engineering solutions to seepage under such conditions, we proposed an approach by combining GIS and the minimum flux in saturation layer (MFSL) method. MFSL can calculate the stable seepage rate by assessing the dominant low permeability layers (including but not limited to the liners) in multi-layered disconnected river-aquifer systems. We used MFSL to calculate local seepage rate, and used GIS to extend the results to a regional scale. The reliability of MFSL is discussed by comparing the results with the double ring infiltration test, the numerical simulation by HYDRUS, and the methods of stream package in MODFLOW, including its improved form. A case study was conducted in the Yongding River with river-aquifer seepage calculated under various conditions, including different river water levels (i.e., under the designated water level, drought stage level, flood stage level and flood inundation level) and with/without low permeability liners (i.e., ecological membranes or geomembrane). Results showed that low permeability liners could greatly reduce the seepage rate. However, if an unlined inundation area exists, the seepage rate may increase greatly. The results indicated that the proposed method was reliable and convenient for calculating long-term, large area seepage in disconnected river-aquifer systems especially those paved with liners.

关键词: infiltration     low permeability liner     multi-layered porous media     river-aquifer seepage    

Mechanical responses of multi-layered ground due to shallow tunneling with arbitrary ground surface load

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 745-762 doi: 10.1007/s11709-023-0935-4

摘要: An analytical model based on complex variable theory is proposed to investigate ground responses due to shallow tunneling in multi-layered ground with an arbitrary ground surface load. The ground layers are assumed to be linear-elastic with full-stick contact between them. To solve the proposed multi-boundary problem, a series of analytic functions is introduced to accurately express the stresses and displacements contributed by different boundaries. Based on the principle of linear-elastic superposition, the multi-boundary problem is converted into a superposition of multiple single-boundary problems. The conformal mappings of different boundaries are independent of each other, which allows the stress and displacement fields to be obtained by the sum of components from each boundary. The analytical results are validated based on numerical and in situ monitoring results. The present model is superior to the classical model for analyzing ground responses of shallow tunneling in multi-layered ground; thus, it can be used with assurance to estimate the ground movement and surface building safety of shallow tunnel constructions beneath surface buildings. Moreover, the solution for the ground stress distribution can be used to estimate the safety of a single-layer composite ground.

关键词: analytical model     mechanical response     multi-layered ground     shallow tunneling     ground surface load     complex variable solution    

Assessing artificial neural network performance for predicting interlayer conditions and layer modulus of multi-layered

Lingyun YOU, Kezhen YAN, Nengyuan LIU

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 487-500 doi: 10.1007/s11709-020-0609-4

摘要: The objective of this study is to evaluate the performance of the artificial neural network (ANN) approach for predicting interlayer conditions and layer modulus of a multi-layered flexible pavement structure. To achieve this goal, two ANN based back-calculation models were proposed to predict the interlayer conditions and layer modulus of the pavement structure. The corresponding database built with ANSYS based finite element method computations for four types of a structure subjected to falling weight deflectometer load. In addition, two proposed ANN models were verified by comparing the results of ANN models with the results of PADAL and double multiple regression models. The measured pavement deflection basin data was used for the verifications. The comparing results concluded that there are no significant differences between the results estimated by ANN and double multiple regression models. PADAL modeling results were not accurate due to the inability to reflect the real pavement structure because pavement structure was not completely continuous. The prediction and verification results concluded that the proposed back-calculation model developed with ANN could be used to accurately predict layer modulus and interlayer conditions. In addition, the back-calculation model avoided the back-calculation errors by considering the interlayer condition, which was barely considered by former models reported in the published studies.

关键词: asphalt pavement     interlayer conditions     finite element method     artificial neural network     back-calculation    

purification of trace thallium(I)-contaminated potable water using a high-selective filter paper with multi-layered

《化学科学与工程前沿(英文)》 doi: 10.1007/s11705-023-2379-8

摘要: Thallium is a highly toxic metal, and trace amount of thallium(I) (Tl+) in potable water could cause a severe water crisis, which arouses the exploitation of highly-effective technology for purification of Tl+ contaminated water. This report proposes the multi-layered Prussian blue (PB)-decorated composite membranes (PBx@PDA/PEI-FP) based on the aminated filter papers for Tl+ uptake. Extensively characterization by Fourier transform infrared spectrometer-attenuated total reflectance, scanning electron microscope, thermogravimetric analysis, X-ray photoelectron spectroscopy and X-ray diffraction were performed to confirm the in situ growth of cubic PB crystals on filter paper membrane surfaces via the aminated layers, and the successful fabrication of multi-layered PB overcoats via the increasing of aminated layers. The effect of PB layers on Tl+ removal by PBx@PDA/PEI-FP from simulated drinking water was evaluated as well as the influence of different experimental conditions. A trade-off between PB decoration layer number and PB distribution sizes is existed in Tl+ uptake by PBx@PDA/PEI-FP. The double-layered PB2@PDA/PEI-FP membrane showed the maximum sorption capacity, but its Tl+ uptake performance was weakened by the acid, coexisting ions (K+ and Na+) and powerful operation pressure, during filtrating a large volume of low-concentrated Tl+-containing water. However, the negative effect of coexisting ions on the Tl+ uptake could be effectively eliminated in weak alkaline water, and the Tl+ removal was increased up to 100% without any pressure driving for PB2@PDA/PEI-FP membrane. Most importantly, PB2@PDA/PEI-FP displayed the high-efficiency and high-selectivity in purifying the Tl+-spiked Pearl River water, in which the residual Tl+ in filtrate was less than 2 μg·L–1 to meet the drinking water standard of United States Environmental Protection Agency. This work provides a feasible avenue to safeguard the drinking water in remote and underdeveloped area via the energy-free operation.

关键词: membrane adsorption     Prussian blue     energy-free filtration     potable water     trace thallium(I)    

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 346-352 doi: 10.1007/s11709-007-0046-7

摘要: Shaking table tests on a dynamic interaction system of hard layered soil, pile foundation and frame structure were carried out. The earthquake damage of the superstructure and foundation was reproduced. Based on these tests, several key issues about the seismic response of the dynamic soil-structure interaction (SSI) system were studied. The natural frequency of the system was less than that of the structure on rigid foundation if the SSI is not taken into account, while its damping ratio was larger than that of the structure. The mode shape of the system was different from that of the structure on the fixed base in that there were rocking and swinging at the foundation. Magnification or reduction of vibration transferred by soil was related to soil characteristic, excitation magnitude, and so on. Generally, sand magnifies vibration, while viscous powder soil dampens vibration. The components of the acceleration response at the top of the superstructure were based on the relative magnitude of the rocking stiffness, the swing stiffness of the foundation and the stiffness of the super-structure. The multi-direction excitations have little effect on the key issues of the horizontal SSI.

关键词: super-structure     Generally     Magnification     frequency     different    

Fabrication of layered structure VS anchor in 3D graphene aerogels as a new cathode material for lithium

《能源前沿(英文)》 2019年 第13卷 第3期   页码 597-602 doi: doi:10.1007/s11708-018-0576-9

摘要: VS4 has gained more and more attention for its high theoretical capacity (449 mAh/g with 3e transfer) in lithium ion batteries (LIBs). Herein, a layered structure VS4 anchored in graphene aerogels is prepared and first reported as cathode material for LIBs. VS4@GAs composite exhibits an exceptional high initial reversible capacity (511 mAh/g), an excellent high-rate capability (191 mAh/g at the 5 C), and an excellent cyclic stability (239 mAh/g after 15 cycles).

关键词: VS4     graphene aerogels     cathode     lithium storage    

Fabrication of layered structure VS

Lijun WU, Yu ZHANG, Bingjiang LI, Pengxiang WANG, Lishuang FAN, Naiqing ZHANG, Kening SUN

《能源前沿(英文)》 2019年 第13卷 第3期   页码 597-602 doi: 10.1007/s11708-018-0576-9

摘要: VS has gained more and more attention for its high theoretical capacity (449 mAh/g with 3e transfer) in lithium ion batteries (LIBs). Herein, a layered structure VS anchored in graphene aerogels is prepared and first reported as cathode material for LIBs. VS @GAs composite exhibits an exceptional high initial reversible capacity (511 mAh/g), an excellent high-rate capability (191 mAh/g at the 5 C), and an excellent cyclic stability (239 mAh/g after 15 cycles).

关键词: VS4     graphene aerogels     cathode     lithium storage    

Uncertain and multi-objective programming models for crop planting structure optimization

Mo LI,Ping GUO,Liudong ZHANG,Chenglong ZHANG

《农业科学与工程前沿(英文)》 2016年 第3卷 第1期   页码 34-45 doi: 10.15302/J-FASE-2016084

摘要: Crop planting structure optimization is a significant way to increase agricultural economic benefits and improve agricultural water management. The complexities of fluctuating stream conditions, varying economic profits, and uncertainties and errors in estimated modeling parameters, as well as the complexities among economic, social, natural resources and environmental aspects, have led to the necessity of developing optimization models for crop planting structure which consider uncertainty and multi-objectives elements. In this study, three single-objective programming models under uncertainty for crop planting structure optimization were developed, including an interval linear programming model, an inexact fuzzy chance-constrained programming (IFCCP) model and an inexact fuzzy linear programming (IFLP) model. Each of the three models takes grayness into account. Moreover, the IFCCP model considers fuzzy uncertainty of parameters/variables and stochastic characteristics of constraints, while the IFLP model takes into account the fuzzy uncertainty of both constraints and objective functions. To satisfy the sustainable development of crop planting structure planning, a fuzzy-optimization-theory-based fuzzy linear multi-objective programming model was developed, which is capable of reflecting both uncertainties and multi-objective. In addition, a multi-objective fractional programming model for crop structure optimization was also developed to quantitatively express the multi-objective in one optimization model with the numerator representing maximum economic benefits and the denominator representing minimum crop planting area allocation. These models better reflect actual situations, considering the uncertainties and multi-objectives of crop planting structure optimization systems. The five models developed were then applied to a real case study in Minqin County, north-west China. The advantages, the applicable conditions and the solution methods of each model are expounded. Detailed analysis of results of each model and their comparisons demonstrate the feasibility and applicability of the models developed, therefore decision makers can choose the appropriate model when making decisions.

关键词: crop planting structure     optimization model     uncertainty     multi-objective    

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    

钢复合结构压力容器技术

朱国辉,朱立,郑津洋,郑传祥,陈志平,吴红梅

《中国工程科学》 2001年 第3卷 第7期   页码 79-84

摘要:

对压力容器设计提出了一种技术先进的多功能壳和长远发展根本要求的新理念,并介绍了钢复合结构压力容器技术的四项新的专利技术发展体系。钢复合结构压力容器技术是一种国际创新的,涵盖各种高、中、低压,应用范围广阔的压力容器新技术。其主要特点是具抑爆抗爆、简化制造、分散缺陷和可实现经济可靠的在线安全状态自动监控等多功能壳特性,可降低制造成本30%~50%。

关键词: 压力容器技术     钢复合结构     多功能壳     钢带错绕     全双层     抑爆抗爆    

Finite element model updating of a large structure using multi-setup stochastic subspace identification

Reza KHADEMI-ZAHEDI, Pouyan ALIMOURI

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 965-980 doi: 10.1007/s11709-019-0530-x

摘要: In the present contribution, operational modal analysis in conjunction with bees optimization algorithm are utilized to update the finite element model of a solar power plant structure. The physical parameters which required to be updated are uncertain parameters including geometry, material properties and boundary conditions of the aforementioned structure. To determine these uncertain parameters, local and global sensitivity analyses are performed to increase the solution accuracy. An objective function is determined using the sum of the squared errors between the natural frequencies calculated by finite element method and operational modal analysis, which is optimized using bees optimization algorithm. The natural frequencies of the solar power plant structure are estimated by multi-setup stochastic subspace identification method which is considered as a strong and efficient method in operational modal analysis. The proposed algorithm is efficiently implemented on the solar power plant structure located in Shahid Chamran university of Ahvaz, Iran, to update parameters of its finite element model. Moreover, computed natural frequencies by numerical method are compared with those of the operational modal analysis. The results indicate that, bees optimization algorithm leads accurate results with fast convergence.

关键词: operational modal analysis     solar power plant structure     multi-setup stochastic subspace     bees optimization algorithm     sensitivity analysis    

构建二维层状结构的稠环含能材料——高能量与高稳定性的平衡 Article

冯永安, 邓沐聪, 宋思维, 陈思同, 张庆华, Jean’ne M. Shreeve

《工程(英文)》 2020年 第6卷 第9期   页码 1006-1012 doi: 10.1016/j.eng.2020.01.013

摘要:

制造具有良好机械感度的高性能含能材料在过去几十年里一直是一项重大挑战,因为这类蕴含巨大能量的材料存在内在的不稳定性。本文研究了一种极具潜力的稠环含能材料:4-硝基-7-叠氮基-吡唑-[3,4-d]-1,2,3-三嗪-2-氧(NAPTO)。这种物质具有不同寻常的二维(2D)层状结构,其绝对结构已经单晶X射线衍射证实。研究显示,这一结构新颖的含能物质具有惊人的能量[如爆速(D)高达9.12 km·s–1,爆压(P)为35.1 GPa]、优异的机械感度[撞击感度(IS)为18 J、摩擦感度(FS)为325 N、静电感度(EDS)为0.32 J]和良好的热分解温度(203.2 ℃),展示出高能量与低感度的双重优势。据我们所知,NAPTO是首个具有二维层状结构的稠环含能材料。与此同时,运用分子模拟分析了其在外界机械刺激下的稳定机制,结果表明,该含能材料超平的二维层状结构比其他结构更能有效地缓冲外界机械刺激,从而将作用在材料上的机械能转化为晶体的层间滑动与压缩。本研究从实验和理论两个方面揭示了稠环二维层状结构在制造先进含能材料方面的巨大潜力。

关键词: 含能材料     稠环杂环化合物     二维层状结构     高能量     稳定性     感度    

Hierarchical fractal structure of perfect single-layer graphene

T. Zhang, K. Ding

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 371-382 doi: 10.1007/s11465-013-0279-1

摘要:

The atomic lattice structure of perfect single-layer graphene that can actually be regarded as a kind of hierarchical fractal structure from the perspective of fractal geometry was studied for the first time. Three novel and special discoveries on hierarchical fractal structure and sets were unveiled upon examination of the regular crystal lattices of the single-layer graphene. The interior fractal-type structure was discovered to be the fifth space-filling curve from physical realm. Two efficient methods for calculating the fractal dimension of this fresh member was also provided. The outer boundary curve had a fractal dimension equal to one, and a multi-fractal structure from a naturally existing material was found for the first time. A series of strict self-similar hexagons comprised a rotating fractal set. These hexagons slewed at a constant counterclockwise angle of 19.1° when observed from one level to the next higher level. From the perspective of fractal geometry, these pioneering discoveries added three new members to the existing regular fractal structures and sets. A fundamental example of a multi-fractal structure was also presented.

关键词: hierarchical fractal structure     fractal dimension     the fifth space-filling curve     multi-fractal structure    

Crack evolution of soft–hard composite layered rock-like specimens with two fissures under uniaxial compression

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1372-1389 doi: 10.1007/s11709-021-0772-2

摘要: Acoustic emission and digital image correlation were used to study the spatiotemporal evolution characteristics of crack extension of soft and hard composite laminated rock masses (SHCLRM) containing double fissures under uniaxial compression. The effects of different rock combination methods and prefabricated fissures with different orientations on mechanical properties and crack coalescence patterns were analyzed. The characteristics of the acoustic emission source location distribution, and frequency changes of the crack evolution process were also investigated. The test results show that the damage mode of SHCLRM is related to the combination mode of rock layers and the orientation of fractures. Hard layers predominantly produce tensile cracks; soft layers produce shear cracks. The first crack always sprouts at the tip or middle of prefabricated fractures in hard layers. The acoustic emission signal of SHCLRM with double fractures has clear stage characteristics, and the state of crack development can be inferred from this signal to provide early warning for rock fracture instability. This study can provide a reference for the assessment of the fracture development status between adjacent roadways in SHCLRM in underground mines, as well as in roadway layout and support.

关键词: soft−hard composite layered rock mass     double cracks     crack evolution     acoustic emission     digital image correlation    

标题 作者 时间 类型 操作

Anisotropy of multi-layered structure with sliding and bonded interlayer conditions

Lingyun YOU, Kezhen YAN, Jianhong MAN, Nengyuan LIU

期刊论文

Quantification of seepage in a multi-layered disconnected river-aquifer system

Jiang LI, Haizhu HU, Xiaomin MAO, Yi LIU

期刊论文

Mechanical responses of multi-layered ground due to shallow tunneling with arbitrary ground surface load

期刊论文

Assessing artificial neural network performance for predicting interlayer conditions and layer modulus of multi-layered

Lingyun YOU, Kezhen YAN, Nengyuan LIU

期刊论文

purification of trace thallium(I)-contaminated potable water using a high-selective filter paper with multi-layered

期刊论文

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

期刊论文

Fabrication of layered structure VS anchor in 3D graphene aerogels as a new cathode material for lithium

期刊论文

Fabrication of layered structure VS

Lijun WU, Yu ZHANG, Bingjiang LI, Pengxiang WANG, Lishuang FAN, Naiqing ZHANG, Kening SUN

期刊论文

Uncertain and multi-objective programming models for crop planting structure optimization

Mo LI,Ping GUO,Liudong ZHANG,Chenglong ZHANG

期刊论文

Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

期刊论文

钢复合结构压力容器技术

朱国辉,朱立,郑津洋,郑传祥,陈志平,吴红梅

期刊论文

Finite element model updating of a large structure using multi-setup stochastic subspace identification

Reza KHADEMI-ZAHEDI, Pouyan ALIMOURI

期刊论文

构建二维层状结构的稠环含能材料——高能量与高稳定性的平衡

冯永安, 邓沐聪, 宋思维, 陈思同, 张庆华, Jean’ne M. Shreeve

期刊论文

Hierarchical fractal structure of perfect single-layer graphene

T. Zhang, K. Ding

期刊论文

Crack evolution of soft–hard composite layered rock-like specimens with two fissures under uniaxial compression

期刊论文