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 23

年份

2023 1

2021 3

2019 1

2018 1

2017 2

2011 1

2009 3

2008 5

2007 1

2006 2

2001 2

1999 1

展开︾

关键词

RLC网络；谐振性质；振荡特性；幅频特性 1

中压变频 1

交通导致振动 1

低压变频 1

信号平稳化 1

分层 1

半主动隔振；双级驱动；动态吸振；可调反共振频率控制器 1

可移动音罩 1

可调混响装置 1

合理电压等级 1

噪声控制 1

大中功率 1

大桥 1

寿命预测 1

峰值供热能力 1

快速可调节性 1

悬索 1

感应电机 1

房间温度分布 1

展开︾

检索范围：

排序：展示方式：

Impact drive rotary precision actuator with piezoelectric bimorphs

ZHANG Hongzhuang, ZENG Ping, HUA Shunming, CHENG Guangming, YANG Zhigang

《机械工程前沿（英文）》 2008年第3卷第1期页码 71-75 doi: 10.1007/s11465-008-0008-3

摘要： An impact drive rotary precision actuator with end-loaded piezoelectric cantilever bimorphs is proposed. According to finite element analysis and experiments of the dynamic characteristics of end-loaded piezoelectric cantilever bimorphs, a specific fixed-frequency and adjustable-amplitude is confirmed to control the actuator. The results show that an actuator excited by fixed-frequency and the adjustable-amplitude ramp voltage waveform works with a large travel range (180°), high resolution (1 ?rad), speed (0.2 rad/min) and heavy-load ability (0.02 Nm). With advantages of high-precision positioning ability, simple structure and only one percent the cost of traditional impact drive mechanisms, the actuator is expected to be widely used in precision industries.

关键词： specific fixed-frequency waveform piezoelectric cantilever mechanisms adjustable-amplitude

HTML PDF 收藏

Characteristics of force acting on adjustable axial flow pump blade

WEI Peiru, CHEN Hongxun, LU Wei

《能源前沿（英文）》 2008年第2卷第4期页码 508-513 doi: 10.1007/s11708-008-0054-x

摘要： The internal three-dimensional turbulent flow of adjustable axial-flow pump arrangement was simulated, and the force acting on the blade surface was calculated under different operating conditions. Based on the calculated results, finite element method (FEM) was adopted to analyze stress and strain distributions of the adjustment blade in different operations. Hydraulic moment, centrifugal moment and friction moment which must be conquered by adjusting the blades were also calculated.

关键词： three-dimensional adjustable axial-flow calculated FEM centrifugal

HTML PDF 收藏

Restoration of hyper-eutrophic water with a modularized and air adjustable constructed submerged plant

Jinzhong LI, Xueju LI, Shujuan SUN, Xuegong LIU, Suiliang HUANG

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 573-584 doi: 10.1007/s11783-011-0363-x

摘要： A modularized and air adjustable constructed submerged plant bed (CSPB) which can be used to restore the eutrophic water is introduced in this paper. This plant bed helps hydrophyte grow under poor conditions such as frequently changed water depth, impaired water transparency, algae bloom and substantial duckweed in summer, which are not naturally suitable for growing hydrophyte. This pilot study in Waihuan River of Tianjin, China, revealed that reduction of Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP) by the use of CSPB could be reached 30%–35%, 35%–40%, 30%–40% respectively in the growing season (from March to October) and 5%–10%, 5%–15%, 7%–20% respectively in the winter (from November to February) when the detention time was 6 d. The relationships between the concentration of COD, TN, TP and the detention time fit the first-order kinetic equation well and the coefficients of determination ( ) were all above 0.9. The attenuation coefficients k of the kinetic equation were a function of the water temperature. When the water temperature was quite low or quite high, was not significantly changed with increasing or decreasing water temperature. While when the temperature was in a moderate range, an increase or decrease of water temperature would lead to a rapid increase or decrease in .

关键词： modularized and air adjustable constructed submerged plant bed water purification eco-restoration techniques aquatic plants eutrophication

HTML PDF 收藏

Design and experimental study of a passive power-source-free stiffness-self-adjustable mechanism

Yuwang LIU, Dongqi WANG, Shangkui YANG, Jinguo LIU, Guangbo HAO

《机械工程前沿（英文）》 2021年第16卷第1期页码 32-45 doi: 10.1007/s11465-020-0604-4

摘要： Passive variable stiffness joints have unique advantages over active variable stiffness joints and are currently eliciting increased attention. Existing passive variable stiffness joints rely mainly on sensors and special control algorithms, resulting in a bandwidth-limited response speed of the joint. We propose a new passive power-source-free stiffness-self-adjustable mechanism that can be used as the elbow joint of a robot arm. The new mechanism does not require special stiffness regulating motors or sensors and can realize large-range self-adaptive adjustment of stiffness in a purely mechanical manner. The variable stiffness mechanism can automatically adjust joint stiffness in accordance with the magnitude of the payload, and this adjustment is a successful imitation of the stiffness adjustment characteristics of the human elbow. The response speed is high because sensors and control algorithms are not needed. The variable stiffness principle is explained, and the design of the variable stiffness mechanism is analyzed. A prototype is fabricated, and the associated hardware is set up to validate the analytical stiffness model and design experimentally.

关键词： variable stiffness mechanism stiffness self-regulation bionic robot modeling

HTML PDF 收藏

大中功率节能调速传动的合理电压等级

马小亮

《中国工程科学》 2001年第3卷第11期页码 80-84

摘要：

大中功率风机和泵采用变频调速可节约大量电能，大部分功率在0.2～2 MW范围中。我国现在200 kW以上的电机多是中压，现行中压电网多为10 kV，选用10 kV直接变频从技术和经济角度看都不太合理。由于变频器输入侧都有变压器，因此电机和变频器没有必要和电网一致。文章讨论不同功率段的合理电压等级以及在电机电压和电网电压不同情况下当变频器出现故障时如何实现旁路工作。

关键词：大中功率节能调速合理电压等级低压变频中压变频旁路

HTML PDF 收藏

Research on direct digital process of inductance sensor

WANG Xuan-ze, YANG Lian-gen, ZHONG Yu-ning

《机械工程前沿（英文）》 2006年第1卷第3期页码 317-322 doi: 10.1007/s11465-006-0023-1

摘要： The equivalent circuit of inductance sensor is analyzed. Amplitude-displacement and phase-displacement equations are deduced for non-ideal carrier wave and inductance parameters. Simulation computation shows the corresponding digital curves. Considering that the traditional process method is an approximate one, a new method is presented to simultaneously obtain the amplitude and phase of output signal of sensor by simultaneity A/D and ellipse fit arithmetic. According to the characteristic of the amplitude-displacement and phase-displacement curves, we obtain displacement by phase and amplitude respectively when the sensor is close to the zero point position and away from other positions on the basis of the experiment. The experiment showed that this method can improve precision of measurement, and it can also work for the whole linear range of sensors even if the magnification is very high.

关键词： traditional corresponding phase-displacement Amplitude-displacement characteristic

HTML PDF 收藏

Control of wind-induced vibration of long-span bridges and tall buildings

GU Ming

《结构与土木工程前沿（英文）》 2007年第1卷第1期页码 51-62 doi: 10.1007/s11709-007-0005-3

摘要： With the rapid increase in scales of structures, research on controlling wind-induced vibration of large-scale structures, such as long-span bridges and super-tall buildings, has been an issue of great concern. For wind-induced vibration of large-scale structures, vibration frequencies and damping modes vary with wind speed. Passive, semiactive, and active control strategies are developed to improve the wind-resistance performance of the structures in this paper. The multiple tuned mass damper (MTMD) system is applied to control vertical bending buffeting response. A new semiactive lever-type tuned mass damper (TMD) with an adjustable frequency is proposed to control vertical bending buffeting and torsional buffeting and flutter in the whole velocity range of bridge decks. A control strategy named sinusoidal reference strategy is developed for adaptive control of wind-induced vibration of super-tall buildings. Multiple degrees of freedom general building aeroelastic model with a square cross-section is tested in a wind tunnel. The results demonstrate that the proposed strategies can reduce vibration effectively, and can adapt to wind-induced vibration control of large-scale structures in the uncertain dynamic circumstance.

关键词： torsional buffeting large-scale semiactive adjustable frequency building aeroelastic

HTML PDF 收藏

Application of a Novel Fuzzy Clustering Method Based on Chaos Immune Evolutionary Algorithm for Edge Detection in Image Processing

《机械工程前沿（英文）》 2006年第1卷第1期页码 85-89 doi: 10.1007/s11465-005-0023-6

摘要：

A novel fuzzy clustering method based on chaos immune evolutionary algorithm (CIEFCM) is presented to solve fuzzy edge detection problems in image processing. In CIEFCM, a tiny disturbance is added to a filial generation group using a chaos variable and the disturbance amplitude is adjusted step by step, which greatly improves the colony diversity of the immune evolution algorithm (IEA). The experimental results show that the method not only can correctly detect the fuzzy edge and exiguous edge but can evidently improve the searching efficiency of fuzzy clustering algorithm based on IEA.

关键词： disturbance amplitude disturbance diversity generation processing

HTML PDF 收藏

New refrigeration system using CO vapor-solid as refrigerant

HUANG Dongping, DING Guoliang, QUACK Hans

《能源前沿（英文）》 2008年第2卷第4期页码 494-498 doi: 10.1007/s11708-008-0070-x

摘要： A refrigerant must be in the vapor-liquid phase in a vapor-compression refrigeration system, therefore, CO cannot be used as a refrigerant for temperatures lower than -56°C because solid CO will form under the triple point temperature of -56°C. A refrigeration system with CO vapor-solid particles as refrigerant is put forward, by which a temperature lower than the triple point is achieved. An adjustable nozzle, a sublimator, a high-pressure regulating valve and a low-pressure regulating valve are used to replace the conventional evaporator. Theoretical cycle analysis of the refrigeration system shows that its COP can be 50% higher than that of the conventional one.

关键词： refrigerant adjustable temperature vapor-compression refrigeration sublimator

HTML PDF 收藏

Controlling nested wrinkle morphology through the boundary effect on narrow-band thin films

Hanyang XU, Tielin SHI, Guanglan LIAO, Qi XIA

《机械工程前沿（英文）》 2019年第14卷第2期页码 235-240 doi: 10.1007/s11465-017-0458-6

摘要： We describe the formation of nested wrinkles created by the thermal mismatch between a narrow-band thin film and a compliant substrate. When a film is described as “narrow-band”, it literally means that the film band width is much shorter than its length; more precisely, it means that the width is comparable with the wavelength of the wrinkles. A silicon mask was used during film sputtering to create narrow-band films on poly (dimethylsiloxane) substrate, thus creating regular boundaries to steer local stresses and control wrinkle morphology. Disordered nano-scale wrinkles were found nested within highly ordered micro-scale sinusoidal wrinkles. The formation of nested wrinkles was explained through the amplitude and wavelength saturation of nano-scale wrinkles. The disordered morphology of nano-scale wrinkles and the highly ordered morphology of micro-scale wrinkles were explained by using the boundary effect.

关键词： nested and hierarchical wrinkles morphology amplitude saturation boundary effect

HTML PDF 收藏

Flow behavior of liquid-solid coupled system of piezoelectric micropump

LU Lijun, WU Jiankang

《机械工程前沿（英文）》 2008年第3卷第1期页码 50-54 doi: 10.1007/s11465-008-0003-8

摘要： This paper employs a shallow water model and the finite element method to approximate periodical flows of a micropump to a two-dimensional thickness-averaged flow. A liquid-solid coupled system equation of the micropump is presented. Through the mode analysis of the liquid-solid coupled system, the first-order natural frequency, diaphragm vibration shape and amplitude-frequency relationship are obtained. The vibration response of the diaphragm is calculated when an external electric field is applied. Based on the thickness-averaged flow equation, the periodical flow of the micropump is studied using the finite volume method to investigate the flow behavior and flow rate-frequency characteristics. Numerical results indicate that an optimal working frequency can be obtained, at which the flow rate of the micropump achieves the maximum when the external electric voltage is fixed.

关键词： amplitude-frequency relationship first-order micropump diaphragm vibration electric

HTML PDF 收藏

Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

《机械工程前沿（英文）》 2008年第3卷第4期页码 400-407 doi: 10.1007/s11465-008-0060-z

摘要： Air-bearings are installed between the stator and the mover of ultra-precision linear stages to suppress vibration and mechanical contact. Spring-damping elements are used to emulate the complex interaction of the finite element model (FEM) developed in this paper and the system dynamic behaviors are analyzed. Through the experimental modal test, the validity and reliability of the model are proven. However, the dynamic characteristics including mode frequency, mode shape, and response amplitude are obviously changed with the position of air-bearings. The combined optimization method is used to optimize the air-bearings position. The best and worst positions are obtained using the dynamic characteristic analysis. The method can be generalized to the connection position of different components in manufacture elements and to implement the system dynamic characteristics optimization when the connection position can be changed.

关键词： manufacture different interaction air-bearings response amplitude

HTML PDF 收藏

Separation and extraction of bridge dynamic strain data

Baijian WU, Zhaoxia LI, Ying WANG, T. H. T. CHAN,

《结构与土木工程前沿（英文）》 2009年第3卷第4期页码 395-400 doi: 10.1007/s11709-009-0049-7

摘要： Through comparing the measured data of dynamic strains due to loading and temperature by the stain gauge and temperature sensor at the same location, the information in the strain data was divided into three parts in the frequency domain by using the defined index named power spectral density (PSD)-ratio index. The three parts are dominated respectively by temperature varying, stresses, and noises and thus can be distinguished from the determined the separatrix frequencies. Also, a simple algorithm was developed to separate the three types of information and to extract the strain caused mainly by structural stresses. As an application of the proposed method, the effect of strain deformation and noises on the fatigue assessment was investigated based on the separated data. The results show that, the determined values of separatrix frequencies are valuable for the monitoring data from other bridges. The algorithm is a multiresolution and hierarchical method, which has been validated as a simple and effective method for data analyses, and is suitable for the compression and preprocessing of the great amount monitoring data and easy to be integrated into the structural health monitoring (SHM) soft system. The strain due to temperature varying attributes a little to the errors of fatigue assessment; however, the noises or random disturbance existed in the monitoring data have much responsibility for the errors, and the main reason is that the random disturbance shifts the real strain/stress amplitude picked up by real structural stress or strain.

关键词： dynamic valuable separatrix strain/stress amplitude frequency

HTML PDF 收藏

变幅载荷下纤维金属层板的疲劳与寿命预测

吴学仁,郭亚军

《中国工程科学》 1999年第1卷第3期页码 35-40

摘要：

文章建立了纤维金属层板等幅疲劳载荷下的疲劳裂纹扩展速率与寿命预测模型。在此基础上对玻璃纤维-铝合金层板（GLARE）的疲劳裂纹扩展与分层扩展行为进行了试验研究，探讨了层板过载疲劳行为的机理，提出了纤维金属层板变幅载荷下疲劳寿命预测的等效裂纹闭合模型，并在GLARE层板上得到了验证。

关键词：纤维金属层板疲劳桥接分层寿命预测

HTML PDF 收藏

Development of electrorheological chip and conducting polymer-based sensor

Xianzhou ZHANG, Weihua LI, Weijia WEN, Yanzhe WU, Gordon WALLACE,

《机械工程前沿（英文）》 2009年第4卷第4期页码 393-396 doi: 10.1007/s11465-009-0043-8

摘要： This paper presents the development of an integrated sensor using two types of smart materials: electrorheological (ER) fluids and conducting polymers (CPs). The developed ER chip worked as an actuator, and it was driven by different voltages and control frequencies. When the four electrodes are controlled synchronously, the diaphragm acts as a vibrator whose frequency can be adjusted in accordance with the frequency of the electrical signals. The response signals of the CP sensor were recorded, and its properties were analyzed. Experimental results show that the amplitude decreases monotonically when the frequency increases, owing to the time delay in the pressure buildup in the ER chip. However, the displacement fluctuation of the diaphragm below 20Hz can be detected clearly even if the value is very low. When the vibration frequency is larger than 20Hz, the CP sensor can hardly detect the displacement fluctuation. Thus, the upper limit frequency that the CP sensor can detect is about 20Hz. The practical applications of this microdevice are also discussed.

关键词： electrorheological (ER) fluids conducting polymer (CP) polydimethylsioxane (PDMS) driving frequency amplitude bubble counter