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Review of pantograph and catenary interaction

Weihua ZHANG, Dong ZOU, Mengying TAN, Ning ZHOU, Ruiping LI, Guiming MEI

《机械工程前沿(英文)》 2018年 第13卷 第2期   页码 311-322 doi: 10.1007/s11465-018-0494-x

摘要:

The application of electrified railway directly promotes relevant studies on pantograph-catenary interaction. With the increase of train running speed, the operating conditions for pantograph and catenary have become increasingly complex. This paper reviews the related achievements contributed by groups and institutions around the world. This article specifically focuses on three aspects: The dynamic characteristics of the pantograph and catenary components, the systems’ dynamic properties, and the environmental influences on the pantograph-catenary interaction. In accordance with the existing studies, future research may prioritize the task of identifying the mechanism of contact force variation. This kind of study can be carried out by simplifying the pantograph-catenary interaction into a moving load problem and utilizing the theory of matching mechanical impedance. In addition, developing a computational platform that accommodates environmental interferences and multi-field coupling effects is necessary in order to further explore applications based on fundamental studies.

关键词: electrified railway     pantograph and catenary interaction     contact force variation     moving load problem     mechanical impedance     multi-field    

Spectral element modeling based structure piezoelectric impedance computation and damage identification

Zhigang GUO, Zhi SUN

《结构与土木工程前沿(英文)》 2011年 第5卷 第4期   页码 458-464 doi: 10.1007/s11709-011-0133-7

摘要: This paper presents a numerical simulation study on electromechanical impedance technique for structural damage identification. The basic principle of impedance based damage detection is structural impedance will vary with the occurrence and development of structural damage, which can be measured from electromechanical admittance curves acquired from PZT patches. Therefore, structure damage can be identified from the electromechanical admittance measurements. In this study, a model based method that can identify both location and severity of structural damage through the minimization of the deviations between structural impedance curves and numerically computed response is developed. The numerical model is set up using the spectral element method, which is promised to be of high numerical efficiency and computational accuracy in the high frequency range. An optimization procedure is then formulated to estimate the property change of structural elements from the electric admittance measurement of PZT patches. A case study on a pin-pin bar is conducted to investigate the feasibility of the proposed method. The results show that the presented method can accurately identify bar damage location and severity even when the measurements are polluted by 5% noise.

关键词: PZT     piezoelectric impedance     optimization     spectral element     damage identification    

stack configuration on interface resistances in reverse electrodialysis by in situ electrochemical impedance

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1480-9

摘要:

• RED performance and stack resistance were studied by EIS and LSV.

关键词: Reverse electrodialysis     Electrochemical impedance spectroscopy     Concentration polarization     Spacer shadow effect    

声学综合无损检测技术

陈积懋

《中国工程科学》 2000年 第2卷 第4期   页码 64-69

摘要:

论述了检测复合材料和胶接结构不连续(缺陷)的新型多模综合无损检测技术。该技术以声与超声检测技术为基础,包含五种不同检测模式,用以检测复合材料与胶接结构的失粘、脱粘、分层、疏松、夹芯压皱及其他缺陷。它适用于复合材料与构件的制造、维修和使用现场。它的适用对象范围广泛,几乎覆盖了现有常用的复合材料和胶接结构。它的检测可靠性高,重复精度好。文章还讨论了组成多膜声学综合胶接检测仪的五种不同检测模式的原理,并从我们和国内外同行的大量实践经验出发,说明了综合无损检测技术的巨大发展前景。

关键词: 声学综合检测     综合无损检测     复合材料无损检测     机械阻抗分析     振动分析     共振检测    

Fuzzy force control of constrained robot manipulators based on impedance model in an unknown environment

LIU Hongyi, WANG Fei, WANG Lei

《机械工程前沿(英文)》 2007年 第2卷 第2期   页码 168-174 doi: 10.1007/s11465-007-0028-4

摘要: To precisely implement the force control of robot manipulators in an unknown environment, a control strategy based on fuzzy prediction of the reference trajectory in the impedance model is developed. The force tracking experiments are executed in an open-architecture control system with different tracking velocities, different desired forces, different contact stiffnesses and different surface figurations. The corresponding force control results are compared and analyzed. The influences of unknown parameters of the environment on the contact force are analyzed based on experimental data, and the tunings of predictive scale factors are illustrated. The experimental results show that the desired trajectory in the impedance model is predicted exactly and rapidly in the cases that the contact surface is unknown, the contact stiffness changes, and the fuzzy force control algorithm has high adaptability to the unknown environment.

关键词: predictive     tracking     corresponding     stiffness     algorithm    

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要: The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词: piezoelectricity     impedance curve     mode shapes     inverse problem     flaw detection     curve shifting    

基于阻抗控制的人机协作范式研究及其机器人装配应用 Article

赵兴炜, 陈沂洺, 钱璐, 陶波, 丁汉

《工程(英文)》 2023年 第30卷 第11期   页码 83-92 doi: 10.1016/j.eng.2022.08.022

摘要:

人-机器人协作由于人和机器人的优势互补而成为一个新兴的研究领域。本文提出了一种基于阻抗控制人机协作理论框架。在人机理论协框架下,人是决策者,机器人是执行者,装配任务提供环境约束。机器人是执行装配动作的主要执行者,具有位置控制、拖动控制、正阻抗控制和负阻抗控制等方式。为了揭示人机协作框架的特点,本文讨论了不同控制模式的切换条件图和人机协同耦合系统的稳定性分析。最后进行了人机协作装配实验,在装配公差为0.08 mm或配合过盈配合时,均可完成装配任务。实验表明,人机协同装配具有人与机器人的互补优势,能够有效地完成复杂的装配任务。

关键词: 人机协作     阻抗控制     机器人装配    

Valveless pumping using a two-stage impedance pump

V. C.-C. LEE, Y. A. ABAKR, K.-C. WOO

《机械工程前沿(英文)》 2013年 第8卷 第3期   页码 311-318 doi: 10.1007/s11465-013-0270-x

摘要:

Impedance pump is defined as a type of valveless pumping mechanism, where an elastic tube is joined with a tube of different impedance, a periodic asymmetrical compression on part of the elastic tube will produce a unidirectional flow. Numerical and experimental studies had been conducted in the past, but little experimental work was found to exploit the principle of multi-stage impedance pumping for fluid transportation. This paper concentrates on the fluid behavior for an open-loop two-stage system experimentally. The aim of this work is to have an insight on the deliverable head and pumping rate of an open-loop two-stage impedance pumping system. This paper generally investigates the effect of different parameters towards the generation of unidirectional flows and composite flow of two opposite directions. Results obtained are of significant values.

关键词: valveless pumping     open-loop     two-stage     unidirectional     composite    

电力系统中对称和/或不对称故障的限流器阻抗优化新方法 None

Mahmoud MODARESI, Hamid LESANI

《信息与电子工程前沿(英文)》 2018年 第19卷 第2期   页码 297-307 doi: 10.1631/FITEE.1601689

摘要: 为给电力网络设计者选择故障限流器(fault current limiters,FCLs)的阻抗类型和阻值,提出一种基于其在网络中的位置计算最佳FCL阻值的新方法。由于阻抗的复杂性,需同时考虑FCL阻抗实部和虚部的代价。FCL阻抗优化的目标函数,是以最小化代价最大限度减少故障电流。虽然最佳FCL阻抗值的计算受其在网络中位置的影响,但选取FCL位置的方法并非本文重点。该FCL阻抗优化方法可用于任何具有对称和/或不对称故障的网络。以一个14总线IEEE网络为例解释该过程。该网络采用的最优FCL阻抗是同时考虑FCL阻抗实部和虚部的大范围代价计算得到的。

关键词: 故障限流器(FCL);FCL阻抗;短路电流;故障电流;电力系统    

A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-023-0747-1

摘要: Capacitive sensors are efficient tools for biophysical force measurement, which is essential for the exploration of cellular behavior. However, attention has been rarely given on the influences of external mechanical and internal electrical interferences on capacitive sensors. In this work, a bionic swallow structure design norm was developed for mechanical decoupling, and the influences of structural parameters on mechanical behavior were fully analyzed and optimized. A bionic feather comb distribution strategy and a portable readout circuit were proposed for eliminating electrostatic interferences. Electrostatic instability was evaluated, and electrostatic decoupling performance was verified on the basis of a novel measurement method utilizing four complementary comb arrays and application-specific integrated circuit readouts. An electrostatic pulling experiment showed that the bionic swallow structure hardly moved by 0.770 nm, and the measurement error was less than 0.009% for the area-variant sensor and 1.118% for the gap-variant sensor, which can be easily compensated in readouts. The proposed sensor also exhibited high resistance against electrostatic rotation, and the resulting measurement error dropped below 0.751%. The rotation interferences were less than 0.330 nm and (1.829 × 10−7)°, which were 35 times smaller than those of the traditional differential one. Based on the proposed bionic decoupling method, the fabricated sensor exhibited overwhelming capacitive sensitivity values of 7.078 and 1.473 pF/µm for gap-variant and area-variant devices, respectively, which were the highest among the current devices. High immunity to mechanical disturbances was maintained simultaneously, i.e., less than 0.369% and 0.058% of the sensor outputs for the gap-variant and area-variant devices, respectively, indicating its great performance improvements over existing devices and feasibility in ultralow biomedical force measurement.

关键词: micro-electro-mechanical system capacitive sensor     bionics     operation instability     mechanical and electrical decoupling     biomedical force measurement    

An investigation on stress distribution effect on multi- piezoelectric energy harvesters

Hailu YANG, Dongwei CAO

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 301-307 doi: 10.1007/s11709-017-0404-z

摘要: With the fast development of piezoelectric materials and due to its green and renewable characteristics, the piezoelectric energy harvesting technology has been paid more and more attention by pavement engineers. The stress distribution will significantly affect the piezoelectric material performance. In this paper, the effects of multiple piezoelectric elements on the generation of electrical energy and output power are studied. In the case of constant external load, the number of the piezoelectric units does not necessarily produce more energy. When the same multi piezoelectric units work together, if the stress state of the piezoelectric units is different, the total output energy affected by the connection mode. For uneven stress distribution, the optimal output mode is that each of the piezoelectric units rectified before connected in parallel.

关键词: piezoelectric transducer     uneven stress     impedance matching     optimal energy output    

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

《结构与土木工程前沿(英文)》 2013年 第7卷 第4期   页码 391-401 doi: 10.1007/s11709-013-0225-7

摘要: The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model, in which the mechanical parameters derived from macro-scale material tests were applied directly to the mortar elements. By comparing the calculated results with those predicted by the Carpinteri and Weibull size effects laws, a series of formulas to convert the macro-scale mechanical parameters of mortar and interface to those at the meso-scale were proposed through a fitting analysis. Based on the proposed formulas, numerical simulation of axial compressive and tensile failure processes of concrete and cement mortar materials, respectively were conducted. The calculated results were a good match with the test results.

关键词: concrete     meso-mechanical model     discrete element method     size effect     mechanical parameter    

Facile synthesis of polyaniline nanorods to simultaneously enhance the mechanical properties and wear

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1254-1266 doi: 10.1007/s11705-023-2297-3

摘要: To enhance the mechanical properties and wear resistance of epoxy resin, polyaniline nanorods were first synthesized using a facile route, and then introduced into the epoxy matrix to yield composites via solution mixing. Several measurements were conducted to investigate the phase structures and compositions of polyaniline nanorods, and their positive influences on the mechanical and tribological properties of epoxy resin were also characterized. The results confirmed that the as-synthesized polyaniline exhibited representative rod-like morphologies and dispersed well in the epoxy matrix, leading to significant enhancements in the tensile strength and elastic modulus of epoxy composites. The highest values of 110.33 MPa and 2.04 GPa were obtained by adding 5%–7% polyaniline nanorods, which were 43% and 62% higher than the pure sample, respectively. The wear rate was increased first and then decreased along with polyaniline nanorods, presenting the lowest value of 2.12 × 10−5 mm3·Nm–1 by adding 5% filler, which was markedly reduced by ca. 70% compared to the control sample. Finally, the possible wear mechanism was proposed and discussed in detail. This study tried to broaden the applications of polyaniline nanorods in the field of tribology.

关键词: epoxy resin     polyaniline nanorods     mechanical property     tribological performance     wear mechanism    

Advances in tissue state recognition in spinal surgery: a review

Hao Qu, Yu Zhao

《医学前沿(英文)》 2021年 第15卷 第4期   页码 575-584 doi: 10.1007/s11684-020-0816-3

摘要: Spinal disease is an important cause of cervical discomfort, low back pain, radiating pain in the limbs, and neurogenic intermittent claudication, and its incidence is increasing annually. From the etiological viewpoint, these symptoms are directly caused by the compression of the spinal cord, nerve roots, and blood vessels and are most effectively treated with surgery. Spinal surgeries are primarily performed using two different techniques: spinal canal decompression and internal fixation. In the past, tactile sensation was the primary method used by surgeons to understand the state of the tissue within the operating area. However, this method has several disadvantages because of its subjectivity. Therefore, it has become the focus of spinal surgery research so as to strengthen the objectivity of tissue state recognition, improve the accuracy of safe area location, and avoid surgical injury to tissues. Aside from traditional imaging methods, surgical sensing techniques based on force, bioelectrical impedance, and other methods have been gradually developed and tested in the clinical setting. This article reviews the progress of different tissue state recognition methods in spinal surgery and summarizes their advantages and disadvantages.

关键词: spinal surgery     tissue state recognition     image     force sensing     bioelectrical impedance    

Thermo-mechanical simulation of frost heave in saturated soils

《结构与土木工程前沿(英文)》   页码 1400-1412 doi: 10.1007/s11709-023-0990-x

摘要: Roads are exposed to various degradation mechanisms during their lifetime. The pavement deterioration caused by the surrounding environment is particularly severe in winter when the humidity and subfreezing temperatures prevail. Frost heave-induced damage is one of the winter-related pavement deterioration. It occurs when the porewater in the soil is exposed to freezing temperatures. The study of frost heave requires conducting a multiphysics analysis, considering the thermal, mechanical, and hydraulic fields. This paper presents the use of a coupled thermo-mechanical approach to simulate frost heave in saturated soils. A function predicting porosity evolution is implemented to couple the thermal and mechanical field analyses. This function indirectly considers the effect of the water seepage inside the soil. Different frost heave scenarios with uniform and non-uniform boundary conditions are considered to demonstrate the capabilities of the method. The results of the simulations indicate that the thermo-mechanical model captures various processes involved in the frost heave phenomenon, such as water fusion, porosity variation, cryogenic suction force generation, and soil expansion. The characteristics and consequences of each process are determined and discussed separately. Furthermore, the results show that non-uniform thermal boundaries and presence of a culvert inside the soil result in uneven ground surface deformations.

关键词: frost heave     multiphysics analysis     thermo-mechanical approach     saturated soils    

标题 作者 时间 类型 操作

Review of pantograph and catenary interaction

Weihua ZHANG, Dong ZOU, Mengying TAN, Ning ZHOU, Ruiping LI, Guiming MEI

期刊论文

Spectral element modeling based structure piezoelectric impedance computation and damage identification

Zhigang GUO, Zhi SUN

期刊论文

stack configuration on interface resistances in reverse electrodialysis by in situ electrochemical impedance

期刊论文

声学综合无损检测技术

陈积懋

期刊论文

Fuzzy force control of constrained robot manipulators based on impedance model in an unknown environment

LIU Hongyi, WANG Fei, WANG Lei

期刊论文

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

期刊论文

基于阻抗控制的人机协作范式研究及其机器人装配应用

赵兴炜, 陈沂洺, 钱璐, 陶波, 丁汉

期刊论文

Valveless pumping using a two-stage impedance pump

V. C.-C. LEE, Y. A. ABAKR, K.-C. WOO

期刊论文

电力系统中对称和/或不对称故障的限流器阻抗优化新方法

Mahmoud MODARESI, Hamid LESANI

期刊论文

A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow

期刊论文

An investigation on stress distribution effect on multi- piezoelectric energy harvesters

Hailu YANG, Dongwei CAO

期刊论文

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

期刊论文

Facile synthesis of polyaniline nanorods to simultaneously enhance the mechanical properties and wear

期刊论文

Advances in tissue state recognition in spinal surgery: a review

Hao Qu, Yu Zhao

期刊论文

Thermo-mechanical simulation of frost heave in saturated soils

期刊论文