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期刊论文 12

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2019 1

2018 1

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2009 2

2008 3

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关键词

RLC网络;谐振性质;振荡特性;幅频特性 1

交通导致振动 1

信号平稳化 1

分层 1

大桥 1

寿命预测 1

悬索 1

振幅分析 1

探地雷达 1

斜拉 1

桥接 1

沙丘 1

疲劳 1

纤维金属层板 1

调幅 1

运行模态分析 1

逆时偏移 1

阻尼 1

非平稳 1

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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    

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    

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    

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    

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    

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    

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    

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    

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    

复杂环境下起伏地形探地雷达逆时偏移成像 Article

John H. Bradford,Janna Privette,David Wilkins,Richard Ford

《工程(英文)》 2018年 第4卷 第5期   页码 661-666 doi: 10.1016/j.eng.2018.09.004

摘要:

探地雷达偏移成像中,基于高程静校正的基准面偏移方法对起伏地表下的复杂地层成像效果较差。为了优化成像效果,本文提出了一种基于麦克斯韦方程组二阶解耦形式的逆时偏移成像(reversetime migration,RTM)算法,该算法特点在于只需计算电场,且可直接从采集面而非基准面进行波场延拓,进而实现地形逆时偏移。数值模拟比较了高程静校正偏移方法和RTM 方法在地表起伏及速度横向变化情况下的成像效果,结果证明RTM 方法成像效果更好。为了进一步验证算法效果,利用美国犹他州珊瑚粉沙丘崎岖地形下的实测数据对两种方法进行了对比分析。研究表明,逆时偏移成像方法能够极大地提高复杂环境下探地雷达深度成像精度。

关键词: 探地雷达     逆时偏移     沙丘     振幅分析    

含有任意边界的m×n阶RLC网络的等效复阻抗特性 Article

Zhi-zhong TAN, Hong ZHU, Jihad H. ASAD, Chen XU, Hua TANG

《信息与电子工程前沿(英文)》 2017年 第18卷 第12期   页码 2070-2081 doi: 10.1631/FITEE.1700037

摘要: 现阶段,精确地计算拓扑网络中任意两节点间等效电阻的技术已经取得较大进展,特别是利用递推-变换(recursion-transform, RT)方法确定含有任意边界的非规则m×n电阻网络的一般等效电阻公式。然而,等效阻抗具有不同于等效电阻的性质,复杂阻抗网络的研究比电阻网络研究困难得多。基于电阻公式,本文研究了含有任意阻抗边界的非规则m×n阶RLC网络的等效复阻抗问题,并发现等效复阻抗的振荡特性和谐振特性。在RLC网络中,当边界阻抗取得一系列特殊值时,复阻抗公式与外部交流电产生共振。结果表明,该公式可以应用到谐振电路中。

关键词: RLC网络;谐振性质;振荡特性;幅频特性    

非平稳环境振动下桥梁的阻尼识别

Sunjoong Kim, Ho-Kyung Kim

《工程(英文)》 2017年 第3卷 第6期   页码 839-844 doi: 10.1016/j.eng.2017.11.002

摘要:
本研究着重于使用非平稳的环境振动数据来识别桥梁的阻尼比。我们通常使用基于输入信号的静态白噪声假设的运行模态分析(OMA)来识别使用中的桥梁的阻尼比。然而,大多数桥梁在使用时通常会受到非平稳激励,而违反这种基本假设会导致阻尼识别的不确定性。为了处理非平稳性,根据测量的响应来计算幅度调制函数,以消除由非平稳输入引起的整体趋势。采用自然激励技术(NExT)-特征系统实现算法(ERA)估算平稳过程中的阻尼比。为了提高基于OMA 的阻尼估计的准确性,在提取的平稳过程和非平稳数据之间进行比较分析,以评估消除非平稳性的效果。在信号平稳化后,第一竖向模态的阻尼比的平均值和标准偏差会减小。

关键词: 阻尼     运行模态分析     交通导致振动     非平稳     信号平稳化     调幅     大桥     斜拉     悬索    

标题 作者 时间 类型 操作

Research on direct digital process of inductance sensor

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

期刊论文

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

期刊论文

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

Hanyang XU, Tielin SHI, Guanglan LIAO, Qi XIA

期刊论文

Flow behavior of liquid-solid coupled system of piezoelectric micropump

LU Lijun, WU Jiankang

期刊论文

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

CHEN Xuedong, LI Zhixin

期刊论文

Separation and extraction of bridge dynamic strain data

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

期刊论文

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

期刊论文

Development of electrorheological chip and conducting polymer-based sensor

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

期刊论文

Impact drive rotary precision actuator with piezoelectric bimorphs

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

期刊论文

复杂环境下起伏地形探地雷达逆时偏移成像

John H. Bradford,Janna Privette,David Wilkins,Richard Ford

期刊论文

含有任意边界的m×n阶RLC网络的等效复阻抗特性

Zhi-zhong TAN, Hong ZHU, Jihad H. ASAD, Chen XU, Hua TANG

期刊论文

非平稳环境振动下桥梁的阻尼识别

Sunjoong Kim, Ho-Kyung Kim

期刊论文