Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 1213

会议视频 57

会议信息 2

年份

2024 2

2023 87

2022 129

2021 114

2020 81

2019 68

2018 62

2017 71

2016 52

2015 58

2014 48

2013 45

2012 42

2011 49

2010 42

2009 57

2008 45

2007 67

2006 35

2005 20

展开︾

关键词

钢结构 8

仿真 7

建筑科学 7

农业科学 6

质量控制 6

三峡工程 5

控制 5

能源 5

智能控制 4

环境 4

不确定性 3

主动控制 3

优化设计 3

模糊控制 3

神经网络 3

稳定性 3

耐久性 3

自适应控制 3

解耦控制 3

展开︾

检索范围：

排序：展示方式：

Optimization of spatial structure designs of control rod using Monte Carlo code RMC

《能源前沿（英文）》 2021年第15卷第4期页码 974-983 doi: 10.1007/s11708-021-0769-5

摘要： Control rod is the most important approach to control reactivity in reactors, which is currently a cluster of pins filled with boron carbide (B₄C). In this case, neutrons are captured in the outer region, and thus the inner absorber is inefficient. Moreover, the lifetime of the control rod is challenged due to the high reactivity worth loss resulted from the excessive degradation of B₄C in the high flux area. In this work, some control rod designs are proposed with optimized spatial structures including the spatially mixed rod, radially moderated rod, and composite control rod with small-sized pins. The control rod worth and effective absorption cross section of these designs are computed using the Monte Carlo code RMC. A long-time depletion calculation is conducted to evaluate their burnup stability. For the spatially mixed rod, rare-earth absorbers are combined with B₄C in spatial structure. Compared with the homogenous B₄C rod, mixed designs ensure more sufficient reactivity worth in the lifetime of the reactor. The minimum reactivity loss at the end of the cycle is only 1.8% from the dysprosium titanate rod, while the loss for pure B₄C rod is nearly 12%. For the radially moderated design, a doubled neutronic efficiency is achieved when the volume ratio of moderator equals approximately 0.3, while excessive moderating may lead to the failure of control rods. The control rod with small-sized pins processes an enhanced safety performance and saves the investment in absorbers. The rod worth can be further enhanced by introducing small moderator pins, and the reactivity loss caused by the reduction of absorbers is sustainable.

关键词： control rod optimized spatial structure neutronic performance burnup stability

HTML PDF 收藏

PID neural network control of a membrane structure inflation system

Qiushuang LIU, Xiaoli XU

《机械工程前沿（英文）》 2010年第5卷第4期页码 418-422 doi: 10.1007/s11465-010-0117-7

摘要： Because it is difficult for the traditional PID algorithm for nonlinear time-variant control objects to obtain satisfactory control results, this paper studies a neuron PID controller. The neuron PID controller makes use of neuron self-learning ability, complies with certain optimum indicators, and automatically adjusts the parameters of the PID controller and makes them adapt to changes in the controlled object and the input reference signals. The PID controller is used to control a nonlinear time-variant membrane structure inflation system. Results show that the neural network PID controller can adapt to the changes in system structure parameters and fast track the changes in the input signal with high control precision.

关键词： PID neural network membrane structure

HTML PDF 收藏

Vibration control of a structure using Magneto-Rheological grease damper

Shinya SUGIYAMA, Tomoki SAKURAI, Shin MORISHITA

《机械工程前沿（英文）》 2013年第8卷第3期页码 261-267 doi: 10.1007/s11465-013-0268-4

摘要：

This paper describes an application study of Magneto-Rheological (MR) grease damper to a structure with three stories. MR fluid is known as one of successful smart materials whose rheological properties can be varied by magnetic field strength, and has been applied to various kinds of device such as dampers, clutches, engine mounts, etc. However, ferromagnetic particles dispersed in MR fluid settle out of the suspension after a certain interval due to the density difference between the particles and their career fluid. To overcome this defect, we have developed a new type of controllable working fluid using grease as the career of magnetic particles. Network of thickener in grease is expected to hold the magnetic particles and prevent them from settled down. No or little sedimentation was observed in MR grease whose characteristics could be controlled by the magnetic field strength. MR grease was introduced into a cylindrical damper and its performance was studied. As a result, it was confirmed that the damping force of MR grease damper could be controlled by the applied electric current to the coil in the cylinder of damper. Furthermore, vibration response of a three-story model structure equipped with MR grease damper was investigated experimentally, and it was shown that MR grease damper worked effectively as a semi-active damper.

关键词： vibration control damper smart material Magneto-Rheological (MR) grease MR fluid

HTML PDF 收藏

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

《结构与土木工程前沿（英文）》 2023年第17卷第5期页码 780-795 doi: 10.1007/s11709-023-0944-3

摘要： Metro shield tunnels under the lateral relaxation of soil (LRS) are susceptible to significant lateral deformations, which jeopardizes the structural safety and waterproofing. However, deformation control standards for such situations have not been clearly defined. Therefore, based on a specific case, a model test is conducted to realize the LRS of a shield tunnel in a sandy stratum to reveal its effect on segment liners. Subsequently, a deformation control criterion is established. The LRS is simulated by linearly reducing the loads applied to the lateral sides of the segment structure. During lateral unloading, the lateral earth pressure coefficient on the segment decreases almost exponentially, and the structural deformation is characterized by horizontal expansion at the arch haunches and vertical shrinkage at the arch vault and arch bottom. Based on the mechanical pattern of the segment structure and the acoustic emission, the deformation response of a segment can be classified into three stages: elastic and quasi-elastic, damage, and rapid deformation development. For a shield tunnel with a diameter of approximately 6 m and under the lateral relaxation of sandy soil, when the ellipticity of the segment is less than 2.71%, reinforcement measures are not required. However, the segment deformation must be controlled when the ellipticity is 2.71% to 3.12%; in this regard, an ellipticity of 3% can be used as a benchmark in similar engineering projects.

关键词： shield tunnel lateral relaxation of soil deformation control criterion of segment structure model test

HTML PDF 收藏

Improving existing “reaching law” for better discrete control of seismically-excited building structures

Zhijun LI, Zichen DENG

《结构与土木工程前沿（英文）》 2009年第3卷第2期页码 111-116 doi: 10.1007/s11709-009-0022-5

摘要： In this paper, a novel “composite reaching law” was explained in details: 1) the equation of discrete motion for a control system; 2) the design of discrete-time variable structure control. In addition, the model of a three-storey shear-type building structure was used to verify the effectiveness of the discrete variable structure control method. The results of numerical example analysis of the model show that the control law can effectively reduce the peak value of seismic response of the building structure and the chattering effect of the control system.

关键词： discrete-time variable structure control composite reaching law chattering effect saturated control law

HTML PDF 收藏

Semi-active vibration control using piezoelectric actuators in smart structures

Jinhao QIU, Hongli JI, Kongjun ZHU

《机械工程前沿（英文）》 2009年第4卷第3期页码 242-251 doi: 10.1007/s11465-009-0068-z

摘要： The piezoelectric materials, as the most widely used functional materials in smart structures, have many outstanding advantages for sensors and actuators, especially in vibration control, because of their excellent mechanical-electrical coupling characteristics and frequency response characteristics. Semi-active vibration control based on state switching and pulse switching has been receiving much attention over the past decade because of several advantages. Compared with standard passive piezoelectric damping, these new semi-passive techniques offer higher robustness. Compared with active damping systems, their implementation does not require any sophisticated signal processing systems or any bulky power amplifier. In this review article, the principles of the semi-active control methods based on switched shunt circuit, including state-switched method, synchronized switch damping techniques, and active control theory-based switching techniques, and their recent developments are introduced. Moreover, the future directions of research in semi-active control are also summarized.

关键词： smart structure semi-active method vibration control piezoelectric actuator

HTML PDF 收藏

Shape control of multi-cellular inflatable panels

N. KATAYAMA, K. ISHIMURA, K. MINESUGI, DANIEL J. INMAN

《机械工程前沿（英文）》 2013年第8卷第3期页码 276-282 doi: 10.1007/s11465-013-0267-5

摘要：

Multi-cellular inflatable structures are ultra-light and robust against membrane damage such as pinholes caused by space debris. Due to their robustness, inflatable structures supported by inner gases can be applied as space structures. In the present study, shape control for a simple multi-cellular inflatable panel was achieved via a novel diaphragm mechanism. When the bending actuator in a center membrane bends, the inner pressures of sub-cells become different, and the diaphragm mechanism bends as a whole. Because a sliding component is not included, this deformable system is a reliable mechanism. In addition, the proposed mechanism has higher rigidity than that of a bending actuator used alone. In the present paper, we investigate the feasibility of a novel diaphragm mechanism and its characteristics using experimental and numerical results.

关键词： Membrane structures inflatable structure shape control smart structures structural mechanics space engineering

HTML PDF 收藏

基于知识的多变量非线性系统变结构解耦控制

涂承媛,曾衍钧

《中国工程科学》 2001年第3卷第10期页码 48-52

摘要：

文章提出了一种基于知识的变结构解耦控制策略，并用于多变量非线性系统的控制，避免了传统解耦控制所必须的建模过程，特别是避免了相应的大量复杂的矩阵运算。阐述了其控制知识库中的一些模块，给出了其算法要点。提出的策略成功地用于一个3×3强耦合系统一三绕组加热标准温度源的恒温控制，得到了温度稳定性和温度均匀性都优于1℃的效果，这是传统方法用于该系统所无法实现的。

关键词：多变量非线性系统解耦控制基于知识的变结构解耦

HTML PDF 收藏

Wind-induced vibration control of Hefei TV tower with fluid viscous damper

Zhiqiang ZHANG , Aiqun LI , Jianping HE , Jianlei WANG ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 249-254 doi: 10.1007/s11709-009-0038-x

摘要： The Hefei TV tower is taken as an analytical case to examine the control method with a fluid viscous damper under wind load fluctuation. Firstly, according to the random vibration theory, the effect of fluctuating wind on the tower can be modeled as a 19-dimensional correlated random process, and the wind-induced vibration analysis of the tower subjected to dynamic wind load was further obtained. On the basis of the others’ works, a bi-model dynamic model is proposed. Finally, a dynamic model is proposed to study the wind-induced vibration control analysis using viscous fluid dampers, and the optimal damping coefficient is obtained regarding the wind-induced response of the upper turret as optimization objectives. Analysis results show that the maximum peak response of the tower under dynamic wind load is far beyond the allowable range of the code. The wind-induced responses and the wind vibration input energy of the tower are decreased greatly by using a fluid viscous damper, and the peak acceleration responses of the upper turret is reduced by 43.4%.

关键词： high-rise structure wind-induced response fluid viscous damper vibration control

HTML PDF 收藏

分阶段成形结构过程控制的无应力状态控制法

秦顺全

《中国工程科学》 2009年第11卷第10期页码 72-78

摘要：

建立了分段成形桥梁任意施工过程的力学平衡方程，由力学平衡方程推演出分阶段施工桥梁过程控制的核心是构件单元的无应力状态量。通过单元的无应力状态量的控制和调整解决了分阶段施工桥梁的安装计算问题；利用无应力状态量一定的前提下，内力和位移与施工过程无关的原理，实现了施工中多工序并行作业，解决了施工中临时荷载和温度影响的自动过滤问题。

关键词：分阶段施工桥梁无应力长度无应力曲率并行作业安装计算

HTML PDF 收藏

Technology improvements and management innovations in construction of Xiluodu hydropower station on Jinsha River

Qixiang FAN

《工程管理前沿（英文）》 2017年第4卷第2期页码 231-237 doi: 10.15302/J-FEM-2017103

摘要： Hongtao ZHOU, Hongwei WANG, Wei ZENG. [J]. Front. Eng, 2018, 5(1): 78-87.Peter REDFERN, Hua ZHONG. [J]. Front. Eng, 2017, 4(2): 193-200.Ming-zhou Liu,Cong-hu Liu,Mao-gen Ge,Yuan Zhang,Qing-hua Zhu. [J]. Front. Eng, 2016, 3(2): 144-146.Chong-guang Feng,Hao Hu,Feng Xu,Jian Yang. [J]. Front. Eng, 2015, 2(2): 178-181.Yu Zhao,Sheng-quan Wang,Ke-chao Zhu. [J]. Front. Eng, 2015, 2(1): 35-38.Ru-gui Chen,Jia-meng Chen. [J]. Front. Eng, 2014, 1(1): 52-61.An Wang. [J]. Front. Eng, 2014, 1(1): 13-17.

关键词： super-high arch dam intelligent construction mass concrete temperature control structure behavior control anti-erosion concrete low-heat portland cement large-discharge and high-velocity spillway tunnels large scale underground powerhouse green hydropower station sustainable development Xiluodu hydropower station

HTML PDF 收藏

航空航天技术与力学

陈士橹

《中国工程科学》 2003年第5卷第3期页码 25-26

摘要：

文章论述了航空航天技术发展与力学学科发展的依存关系，讨论了力学学科间的交叉及交叉学科的产生，重点介绍了飞行力学与空气动力学、结构力学、一般力学、自动控制等学科间的关系，进而讨论了飞行力学的分支——弹性飞行器动力学。

关键词：空气动力学结构力学一般力学自动控制飞行力学弹性飞行器动力学

HTML PDF 收藏

Study on the growth of platinum nanowires as cathode catalysts in proton exchange membrane fuel cells

Ruiqing Wang, Xiaolan Cao, Sheng Sui, Bing Li, Qingfeng Li

《化学科学与工程前沿（英文）》 2022年第16卷第3期页码 364-375 doi: 10.1007/s11705-021-2052-z

摘要： The platinum nanowires have been verified to be a promising catalyst to promote the performance of proton exchange membrane fuel cells. In this paper, accurately controlled growth of nanowires in a carbon matrix is achieved for reducing Pt loading. The effects of formic acid concentration and reaction temperature on the morphology and size of the Pt nanowires, as well as their electrochemical performances in a single cell, are investigated. The results showed that the increase in the formic acid concentration results in a volcano trend with the length of Pt nanowires. With increasing reduction temperature, the diameter of Pt nanowires increases while Pt particles evolve from one-dimensional to zero-dimensional up to 40 °C. A mechanism of the Pt nanowires growth is proposed. The optimized Pt nanowires electrode exhibits a power density (based on electrochemical active surface area) 79% higher than conventional Pt/C one. The control strategy obtained contributes to the design and control of novel nanostructures in nano-synthesis and catalyst applications.

关键词： Pt nanowires morphology structure control in situ growth mechanism proton exchange membrane fuel cells

HTML PDF 收藏

Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics

《环境科学与工程前沿（英文）》 2021年第15卷第6期 doi: 10.1007/s11783-021-1419-1

摘要：

• Pore structure affects biologically activated carbon performance.

关键词： Granular activated carbon Biologically activated carbon filter Bacterial community structure Pore structure

HTML PDF 收藏

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