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Fracture behavior of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric material

Junhong GUO, Zixing LU

《机械工程前沿(英文)》 2011年 第6卷 第3期   页码 296-300 doi: 10.1007/s11465-011-0236-9

摘要:

Based on the Stroh-type formalism and the technique of conformal mapping, the problem of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric solid is investigated under remotely uniform in-plane electric loading and anti-plane mechanical loading, which allowed us to take the electric field inside the hole and cracks into account. The analytical solutions of the field intensity factors and the energy release rate are presented in closed-form, which includes the extreme cases for an impermeable crack and a permeable crack. Numerical results are then presented to reveal the effects of geometrical parameters, crack permeability and combined mechanical and electric loadings on the energy release rate.

关键词: piezoelectric materials     elliptical hole     semi-permeable crack     energy release rate     analytic solution    

Practical evaluation for water utilities in China by using analytic hierarchy process

Hong CHEN,Feng XIAO,Zhe BI,Ping XIAO,Dongsheng WANG,Ming YANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 131-137 doi: 10.1007/s11783-014-0718-1

摘要: The risk of water utilities would include the water quality failure and the water quantity failure, from the source to the tap, including the catchment, treatment, distribution and the customer plumbing system. In this paper, we proposed a practical evaluation method based on the analytic hierarchy process (AHP). The hierarchical structure of the water utilities was established in terms of the fault event analysis from the past failure accidents. The severity of criteria was preset by the experts and the probability of criteria was determined by a modified CUWA-TSM sheet with the consideration of the actual situations of the supply system. The evaluation model was successfully performed by a case study. Although, the method in this paper may not be as good as the framework of WSPs, it has a great advantage compared to WSPs and TSM. The risk management can be applied through specific software packages with a user-friendly interface, which means it is easier to implement. In addition, it can point out the critical control points (CCPs) for the decision-makers. So we believe this method will improve and play a more and more active role in the development of the risk management in China water works.

关键词: analytic hierarchy process (AHP)     risk management     water quality failure     water quantity failure    

Influencing factors and control measures of excavation on adjacent bridge foundation based on analytic

Shuangxi FENG, Huayang LEI, Yongfeng WAN, Haiyan JIN, Jun HAN

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 461-477 doi: 10.1007/s11709-021-0705-0

摘要: Many uncertain factors in the excavation process may lead to excessive lateral displacement or over-limited internal force of the piles, as well as inordinate settlement of soil surrounding the existing bridge foundation. Safety control is pivotal to ensuring the safety of adjacent structures. In this paper, an innovative method is proposed that combines an analytic hierarchy process (AHP) with a finite element method (FEM) to reveal the potential impact risk of uncertain factors on the surrounding environment. The AHP was adopted to determine key influencing factors based on the weight of each influencing factor. The FEM was used to quantify the impact of the key influencing factors on the surrounding environment. In terms of the AHP, the index system of uncertain factors was established based on an engineering investigation. A matrix comparing the lower index layer to the upper index layer, and the weight of each influencing factor, were calculated. It was found that the excavation depth and the distance between the foundation pit and the bridge foundation were fundamental factors. For the FEM, the FE baseline model was calibrated based on the case of no bridge surrounding the foundation pit. The consistency between the monitoring data and the numerical simulation data for a ground settlement was analyzed. FE simulations were then conducted to quantitatively analyze the degree of influence of the key influencing factors on the bridge foundation. Furthermore, the lateral displacement of the bridge pile foundation, the internal force of the piles, and the settlement of the soil surrounding the pile foundation were emphatically analyzed. The most hazardous construction condition was also determined. Finally, two safety control measures for increasing the numbers of support levels and the rooted depths of the enclosure structure were suggested. A novel method for combining AHP with FEM can be used to determine the key influencing aspects among many uncertain factors during a construction, which can provide some beneficial references for engineering design and construction.

关键词: deep foundation pit excavation     adjacent bridge foundation     influencing factors     analytic hierarchy process     finite element    

Application of fuzzy analytic hierarchy process model on determination of optimized pile-type

Lei MA, Shuilong SHEN, Jinhui ZHANG, Yang HUANG, Feng SHI

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 252-257 doi: 10.1007/s11709-010-0017-2

摘要: Pile-type selection is a very important stage of foundation design, and there are many field factors influencing the decision of pile-type selection. Since there is a limitation of traditional “major factors method” to satisfy the requirement of modern foundation construction, this study presents an efficient approach, in which analytic hierarchy process (AHP) is employed. AHP is a multiple criteria decision-making tool that has been applied in many fields related to the decision-making, e.g., in the field of economics, marketing, sociology, etc. However, it is rarely reported that AHP is applied in the field of civil engineering for decision making. In this study, AHP combined with fuzzy synthetic evaluation method is employed to select the type of pile used as the foundation of a residential building in Fuzhou, Fujian Province, China. The results show that fuzzy AHP approach is an easy and efficient way for pile-type selection.

关键词: pile type     fuzzy synthetic evaluation     analytic hierarchy process (AHP)     optimal selection    

A review of optimization modeling and solution methods in renewable energy systems

《工程管理前沿(英文)》   页码 640-671 doi: 10.1007/s42524-023-0271-3

摘要: The advancement of renewable energy (RE) represents a pivotal strategy in mitigating climate change and advancing energy transition efforts. A current of research pertains to strategies for fostering RE growth. Among the frequently proposed approaches, employing optimization models to facilitate decision-making stands out prominently. Drawing from an extensive dataset comprising 32806 literature entries encompassing the optimization of renewable energy systems (RES) from 1990 to 2023 within the Web of Science database, this study reviews the decision-making optimization problems, models, and solution methods thereof throughout the renewable energy development and utilization chain (REDUC) process. This review also endeavors to structure and assess the contextual landscape of RES optimization modeling research. As evidenced by the literature review, optimization modeling effectively resolves decision-making predicaments spanning RE investment, construction, operation and maintenance, and scheduling. Predominantly, a hybrid model that combines prediction, optimization, simulation, and assessment methodologies emerges as the favored approach for optimizing RES-related decisions. The primary framework prevalent in extant research solutions entails the dissection and linearization of established models, in combination with hybrid analytical strategies and artificial intelligence algorithms. Noteworthy advancements within modeling encompass domains such as uncertainty, multienergy carrier considerations, and the refinement of spatiotemporal resolution. In the realm of algorithmic solutions for RES optimization models, a pronounced focus is anticipated on the convergence of analytical techniques with artificial intelligence-driven optimization. Furthermore, this study serves to facilitate a comprehensive understanding of research trajectories and existing gaps, expediting the identification of pertinent optimization models conducive to enhancing the efficiency of REDUC development endeavors.

关键词: renewable energy system     bibliometrics     mathematical programming     optimization models     solution methods    

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要: This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词: numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 350-359 doi: 10.1007/s11465-013-0271-9

摘要:

Cable-suspended manipulators are used in large scale applications with, heavy in weight and long in span cables. It seems impractical to maintain cable assumptions of smaller robots for large scale manipulators. The interactions among the cables, platforms and actuators can fully evaluate the coupled dynamic analysis. The structural flexibility of the cables becomes more pronounced in large manipulators. In this paper, an analytic solution is provided to solve cable vibration. Also, a closed form solution can be adopted to improve the dynamic response to flexibility. The output is provided by the optimal torque generation subject to the actuator limitations in a mechatronic sense. Finally, the performance of the proposed algorithm is examined through simulations.

关键词: parallel robot     flexible cable     suspended robot     dynamic    

Solution properties and self-association of multi-blocks like copolymer P(AM/AA) prepared by template

ZHANG Yuxi, WU Feipeng, LI Miaozhen, WANG Erjian

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 68-71 doi: 10.1007/s11705-007-0014-8

摘要: The association and properties of multi-block like copolymers (TP) of acrylamide (AM) and acrylic acid (AA) prepared by template copolymerization in aqueous solution were studied. The results showed that the copolymers of this type exhibited a significant structure effect compared with that of similar random copolymers (CP) obtained by copolymerization in the absence of template. Decreasing the value of pH or adding Ca ion to the copolymer solution will make phase separation occur. The TEM images demonstrated that the phase separation caused by Ca ion was due to the formation of extensively intermolecular cross-linking. With the increase of the pH value of copolymer solution, the changes of the solution viscosity was similar with that of homopolyacrylic acid, which originally increased and then decreased. But the increase range of template copolymer was higher than that of homopolyacrylic acid. TEM images indicated that at the maximal viscosity the copolymer obtained in the presence of template formed coiled aggregates.

关键词: aqueous solution     homopolyacrylic     copolymer solution     significant structure     presence    

Yue’s solution of classical elasticity in

Zhong-qi Quentin YUE

《结构与土木工程前沿(英文)》 2015年 第9卷 第3期   页码 215-249 doi: 10.1007/s11709-015-0298-6

摘要: This paper presents the exact and complete fundamental singular solutions for the boundary value problem of a -layered elastic solid of either transverse isotropy or isotropy subject to body force vector at the interior of the solid. The layer number is an arbitrary nonnegative integer. The mathematical theory of linear elasticity is one of the most classical field theories in mechanics and physics. It was developed and established by many well-known scientists and mathematicians over 200 years from 1638 to 1838. For more than 150 years from 1838 to present, one of the remaining key tasks in classical elasticity has been the mathematical derivation and formulation of exact solutions for various boundary value problems of interesting in science and engineering. However, exact solutions and/or fundamental singular solutions in closed form are still very limited in literature. The boundary-value problems of classical elasticity in -layered and graded solids are also one of the classical problems challenging many researchers. Since 1984, the author has analytically and rigorously examined the solutions of such classical problems using the classical mathematical tools such as Fourier integral transforms. In particular, he has derived the exact and complete fundamental singular solutions for elasticity of either isotropic or transversely isotropic layered solids subject to concentrated loadings. The solutions in -layered or graded solids can be calculated with any controlled accuracy in association with classical numerical integration techniques. Findings of this solution formulation are further used in the companion paper for mathematical verification of the solutions and further applications for exact and complete solutions of other problems in elasticity, elastodynamics, poroelasticty and thermoelasticity. The mathematical formulations and solutions have been named by other researchers as Yue’s approach, Yue’s treatment, Yue’s method and Yue’s solution.

关键词: elasticity     solution     layered solid     graded material    

Simplified analytical solution for free vibration characteristics of Hardfill dam

XIAO Wei, HE Yunlong, ZHANG Yanfeng

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 219-225 doi: 10.1007/s11709-008-0037-3

摘要: Formulas for computing natural frequencies and modes of Hardfill dams are derived based on one-dimensional shear wedge theory, in which the influences of the upstream concrete face and hydrodynamic pressure of water on the dams’ natural frequencies and modes are discussed. Furthermore, the seismic responses of Hardfill dams are calculated using response spectrum method. An example is analyzed to compare the differences of natural frequencies and modes between shear wedge method and FEM. Then the applicability and accuracy of shear wedge method to analyze free vibration characteristics of Hardfill dams are proven.

关键词: upstream concrete     hydrodynamic pressure     vibration     one-dimensional     applicability    

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 329-333 doi: 10.1007/s11709-007-0043-x

摘要: Based on the unified strength theory [1], a unified strength criterion for strain softening materials, such as concrete or rock, was derived, and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given. In addition, the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to internal radius,/, the coefficient , which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree, the ratio of tensile strength to compressed strength of the material, , and the damage variable

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1480-1493 doi: 10.1007/s11709-021-0776-y

摘要: In waterfront geotechnical engineering, seismic and drainage conditions must be considered in the design of retaining structures. This paper proposes a general analytical method to evaluate the seismic active earth pressure on a retaining wall with backfill subjected to partial steady seepage flow under seismic conditions. The method comprises the following steps: i) determination of the total head, ii) upper bound solution of seismic active earth thrust, and iii) deduction for the earth pressure distribution. The determination of total head h(x,z) relies on the Fourier series expansions, and the expressions of the seismic active earth thrust and pressure are derived by using the upper bound theorem. Parametric studies reveal that insufficient drainage and earthquakes are crucial factors that cause unfavorable earth pressure. The numerical results confirm the validity of the total head distribution. Comparisons indicate that the proposed method is consistent with other relevant existing methods in terms of predicting seismic active earth pressure. The method can be applied to the seismic design of waterfront retaining walls.

关键词: seismic active earth pressure     partial seepage flow     pore pressure     anisotropy     upper bound theorem    

Enhanced solution representations for vehicle routing problems with split deliveries

《工程管理前沿(英文)》   页码 483-498 doi: 10.1007/s42524-023-0259-z

摘要: In this study, we investigate a forest-based solution representation for split delivery vehicle routing problems (SDVRPs), which have several practical applications and are among the most difficult vehicle routing problems. The new solution representation fully reflects the nature of split delivery, and can help reduce the search space when used in heuristic algorithms. Based on the forest structure, we devise three neighborhood search operators. To highlight the effectiveness of this solution representation, we integrate these operators into a standard tabu search framework. We conduct extensive experiments on three main SDVRPs addressed in the literature: The basic SDVRP, the multidepot SDVRP, and the SDVRP with time windows. The experimental results show that the new forest-based solution representation is particularly effective in designing and implementing neighborhood operators, and that our new approach outperforms state-of-the-art algorithms on standard datasets.

关键词: vehicle routing     multidepot     time windows     tabu search     split delivery    

Additives effects on crystallization and morphology in a novel caustic aluminate solution decomposition

Ying ZHANG, Shili ZHENG, Yifei ZHANG, Hongbin XU, Yi ZHANG

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 88-92 doi: 10.1007/s11705-009-0133-5

摘要: A novel process of caustic aluminate solution decomposition by alcohol medium was developed by the Institute of Process Engineering, Chinese Academy of Sciences in order to solve the problem of low decomposition ratio in the traditional Bayer seeded hydrolysis process. In this research, effects of additives on the crystallization ratio, secondary particle size and morphology of aluminum hydroxide in the new process were studied to obtain high-quality products. On the basis of primary selection of additives, an orthogonal design L9(3 ) was used as a chemometric method to investigate the effects of additives. The studied parameters include the reaction style, quantity of additives, caustic soda concentration, as well as the combination manner. The crystallization ratios of sodium aluminate solution and crystal size of aluminum hydroxide, determined by ICP-OES, SEM and MLPSA (Malvern Laser Particle Size Analyzer), were used to evaluate the effects of the additives. The results showed that different combination manners could promote agglomeration or dispersion. An additive composed by Tween 80 and PEG 200 could promote agglomeration, while a spot of PEG species had a relatively strong dispersion effect. However, the additives had little effects on the crystallization ratios. According to the Raman spectra result, the added alcohol medium might serve as a kind of solvent.

关键词: additive     crystallization     morphology     caustic aluminate solution     aluminium hydroxide    

连轧张力公式的实验验证和分析

张进之,赵厚信,王喆,王保罗

《中国工程科学》 2008年 第10卷 第4期   页码 73-77

摘要:

连轧张力公式是连轧理论和实践的核心问题,该问题国内外都有大量的研究,20世纪60年代笔者推导了连轧张力微分方程、多机架动态张力公式、稳态张力公式,理论上已作过深入、广泛的分析讨论。日本在20世纪70年代对连轧张力公式进行了理论上的推导和实验验证,特别是浅川基男等人的连轧实验结果更为重要。为此引用了浅川基男的实验数据和宝钢2 050 mm热连轧机上的实测数据,验证了连轧张力公式。

关键词: 连轧张力公式     实验验证     解析解     定常性    

标题 作者 时间 类型 操作

Fracture behavior of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric material

Junhong GUO, Zixing LU

期刊论文

Practical evaluation for water utilities in China by using analytic hierarchy process

Hong CHEN,Feng XIAO,Zhe BI,Ping XIAO,Dongsheng WANG,Ming YANG

期刊论文

Influencing factors and control measures of excavation on adjacent bridge foundation based on analytic

Shuangxi FENG, Huayang LEI, Yongfeng WAN, Haiyan JIN, Jun HAN

期刊论文

Application of fuzzy analytic hierarchy process model on determination of optimized pile-type

Lei MA, Shuilong SHEN, Jinhui ZHANG, Yang HUANG, Feng SHI

期刊论文

A review of optimization modeling and solution methods in renewable energy systems

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

期刊论文

Solution properties and self-association of multi-blocks like copolymer P(AM/AA) prepared by template

ZHANG Yuxi, WU Feipeng, LI Miaozhen, WANG Erjian

期刊论文

Yue’s solution of classical elasticity in

Zhong-qi Quentin YUE

期刊论文

Simplified analytical solution for free vibration characteristics of Hardfill dam

XIAO Wei, HE Yunlong, ZHANG Yanfeng

期刊论文

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

期刊论文

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

期刊论文

Enhanced solution representations for vehicle routing problems with split deliveries

期刊论文

Additives effects on crystallization and morphology in a novel caustic aluminate solution decomposition

Ying ZHANG, Shili ZHENG, Yifei ZHANG, Hongbin XU, Yi ZHANG

期刊论文

连轧张力公式的实验验证和分析

张进之,赵厚信,王喆,王保罗

期刊论文