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Preload characteristics identification of the piezoelectric-actuated 1-DOF compliant nanopositioning

Ruizhou WANG, Xianmin ZHANG

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 20-36 doi: 10.1007/s11465-015-0328-z

摘要：

Packaged piezoelectric ceramic actuators (PPCAs) and compliant mechanisms are attractive for nanopositioning and nanomanipulation due to their ultra-high precision. The way to create and keep a proper and steady connection between both ends of the PPCA and the compliant mechanism is an essential step to achieve such a high accuracy. The connection status affects the initial position of the terminal moving plate, the positioning accuracy and the dynamic performance of the nanopositioning platform, especially during a long-time or high-frequency positioning procedure. This paper presents a novel external preload mechanism and tests it in a 1-degree of freedom (1-DOF) compliant nanopositioning platform. The 1-DOF platform utilizes a parallelogram guiding mechanism and a parallelogram load mechanism to provide a more accurate actual input displacement and output displacement. The simulation results verify the proposed stiffness model and dynamic model of the platform. The values of the preload displacement, actual input displacement and output displacement can be measured by three capacitive sensors during the whole positioning procedure. The test results show the preload characteristics vary with different types or control modes of the PPCA. Some fitting formulas are derived to describe the preload displacement, actual input displacement and output displacement using the nominal elongation signal of the PPCA. With the identification of the preload characteristics, the actual and comprehensive output characteristics of the PPCA can be obtained by the strain gauge sensor (SGS) embedded in the PPCA.

关键词： nanopositioning     preload characteristic     packaged piezoelectric ceramic actuator     compliant mechanism    

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Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 32-36 doi: 10.1007/s11465-007-0005-y

摘要： The research about hysteresis characteristic of finger seal (FS), which was carried out based on the model with static loads, could not reflect the dynamics behavior of FS system when the rotor runs at high speed. To solve this problem, the relations between the dynamics parameters, structure parameters as well as working parameters in the system were given out through the analysis of finite element analysis result. A mass spring damper dynamics model of FS system was proposed and the hysteresis characteristic of the FS system was analyzed. This work shows that the dynamics characteristic analysis of the FS is necessary and the dynamics model proposed in this paper is valid. This dynamics model is the basis for the optimization design of FS system.

关键词： FS     necessary     hysteresis characteristic     optimization     spring    

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Inverse identification of the mechanical parameters of a pipeline hoop and analysis of the effect of preload

Ye GAO, Wei SUN

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 358-368 doi: 10.1007/s11465-019-0539-9

摘要： To create a dynamic model of a pipeline system effectively and analyze its vibration characteristics, the mechanical characteristic parameters of the pipeline hoop, such as support stiffness and damping under dynamic load, must be obtained. In this study, an inverse method was developed by utilizing measured vibration data to identify the support stiffness and damping of a hoop. The procedure of identifying such parameters was described based on the measured natural frequencies and amplitudes of the frequency response functions (FRFs) of a pipeline system supported by two hoops. A dynamic model of the pipe-hoop system was built with the finite element method, and the formulas for solving the FRF of the pipeline system were provided. On the premise of selecting initial values reasonably, an inverse identification algorithm based on sensitivity analysis was proposed. A case study was performed, and the mechanical parameters of the hoop were identified using the proposed method. After introducing the identified values into the analysis model, the reliability of the identification results was validated by comparing the predicted and measured FRFs of the pipeline. Then, the developed method was used to identify the support stiffness and damping of the pipeline hoop under different preloads of the bolts. The influence of preload was also discussed. Results indicated that the support stiffness and damping of the hoop exhibited frequency-dependent characteristics. When the preloads of the bolts increased, the support stiffness increased, whereas the support damping decreased.

关键词： inverse identification     pipeline hoop     frequency response function     mechanical parameters     preload    

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Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 470-476 doi: 10.1007/s11783-009-0143-z

摘要： A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH―N<5mg/L, and TN<15mg/L) in China now.

关键词： airlift oxidation ditch     flow characteristic     wastewater treatment    

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Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 357-366 doi: 10.1007/s11465-017-0423-4

摘要：

Given the weak early degradation characteristic information during early fault evolution in gearbox of wind turbine generator, traditional singular value decomposition (SVD)-based denoising may result in loss of useful information. A weak characteristic information extraction based on µ-SVD and local mean decomposition (LMD) is developed to address this problem. The basic principle of the method is as follows: Determine the denoising order based on cumulative contribution rate, perform signal reconstruction, extract and subject the noisy part of signal to LMD and µ-SVD denoising, and obtain denoised signal through superposition. Experimental results show that this method can significantly weaken signal noise, effectively extract the weak characteristic information of early fault, and facilitate the early fault warning and dynamic predictive maintenance.

关键词： wind turbine generator gearbox     µ-singular value decomposition     local mean decomposition     weak characteristic information extraction     early fault warning    

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Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 840-854 doi: 10.1007/s11465-021-0643-5

摘要： In this paper, an improved fractal interpolation model is proposed to reconstruct the surface topography of composite hole wall. This model adopts the maximum positive deviations and maximum negative deviations between the measured values and trend values to determine the contraction factors. Hole profiles in 24 directions are measured. Fractal parameters are calculated to evaluate the measured surface profiles. The maximum and minimum fractal dimension of the hole wall are 1.36 and 1.07, whereas the maximum and minimum fractal roughness are 4.05 × 10 −5 and 4.36 × 10 −10 m, respectively. Based on the two-dimensional evaluation results, three-dimensional surface topographies in five typical angles (0°, 45°, 90°, 135°, and 165°) are reconstructed using the improved model. Fractal parameter D s and statistical parameters Sa, Sq, and Sz are used to evaluate the reconstructed surfaces. Average error of D s, Sa, Sq, and Sz between the measured surfaces and the reconstructed surfaces are 1.53%, 3.60%, 5.60%, and 9.47%, respectively. Compared with the model in published literature, the proposed model has equal reconstruction effect in relatively smooth surface and is more advanced in relatively rough surface. Comparative results prove that the proposed model for calculating contraction factors is more reasonable.

关键词： surface topography     fractal evaluation     fractal interpolation     reconstruction     composite    

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Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 127-132 doi: 10.1007/s11709-013-0200-3

摘要： Prefabricated ultra-thin radiant heating panel, as a new heating terminal type, is becoming a highlight in Yangtze River Valley area, China recently. However, there is a lack of operating characteristic research in this region, especially the energy consumption and operating mode are even less. To obtain these data, a heating system was set up in a duplex house in Chongqing. The test results show that the floor heating system could almost satisfy thermal comfort requirement at supply water temperature 45°C. But the preheating time was up to 4.5 h which was 1 h longer than that at supply water temperature 50°C. Meanwhile, the energy consumption at supply water temperature 50°C increased 0.10 Nm /h, and the operating efficiency decrease about 2.6% compared to those at water temperature 45°C. Considering both the thermal lag and operating efficiency, a reasonable suggestion was proposed in this paper. That was, the standard families which just stay home at night should adopt the interim mode of partial room with part time. And the supply water temperature should be properly raised during the preheating period and lowered down in the steady heating stage.

关键词： ultra-thin floor heating panel     the preheating time     thermal comfort     energy saving    

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Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0735-x

摘要： Servo-hydraulic actuators (SHAs) are widely used in mechanical equipment to drive heavy-duty mechanisms. However, their energy efficiency is low, and their motion characteristics are inevitably affected by uncertain nonlinearities. Electromechanical actuators (EMAs) possess superior energy efficiency and motion characteristics. However, they cannot easily drive heavy-duty mechanisms because of weak bearing capacity. This study proposes and designs a novel electromechanical-hydraulic hybrid actuator (EMHA) that integrates the advantages of EMA and SHA. EMHA mainly features two transmission mechanisms. The piston of the hydraulic transmission mechanism and the ball screw pair of the electromechanical transmission mechanism are mechanically fixed together through screw bolts, realizing the integration of two types of transmission mechanisms. The control scheme of the electromechanical transmission mechanism is used for motion control, and the hydraulic transmission mechanism is used for power assistance. Then, the mathematical model, structure, and parameter design of the new EMHA are studied. Finally, the EMHA prototype and test platform are manufactured. The test results prove that the EMHA has good working characteristics and high energy efficiency. Compared with the valve-controlled hydraulic cylinder system, EMHA exhibits a velocity tracking error and energy consumption reduced by 49.7% and 54%, respectively, under the same working conditions.

关键词： electromechanical-hydraulic hybrid actuator (EMHA)     integration     transmission mechanisms     power assistance     energy efficiency     working characteristics    

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Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要： Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词： gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

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Macro-architectured cellular materials: Properties, characteristic modes, and prediction methods

Zheng-Dong MA

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 442-459 doi: 10.1007/s11465-018-0488-8

摘要：

Macro-architectured cellular (MAC) material is defined as a class of engineered materials having configurable cells of relatively large (i.e., visible) size that can be architecturally designed to achieve various desired material properties. Two types of novel MAC materials, negative Poisson’s ratio material and biomimetic tendon reinforced material, were introduced in this study. To estimate the effective material properties for structural analyses and to optimally design such materials, a set of suitable homogenization methods was developed that provided an effective means for the multiscale modeling of MAC materials. First, a strain-based homogenization method was developed using an approach that separated the strain field into a homogenized strain field and a strain variation field in the local cellular domain superposed on the homogenized strain field. The principle of virtual displacements for the relationship between the strain variation field and the homogenized strain field was then used to condense the strain variation field onto the homogenized strain field. The new method was then extended to a stress-based homogenization process based on the principle of virtual forces and further applied to address the discrete systems represented by the beam or frame structures of the aforementioned MAC materials. The characteristic modes and the stress recovery process used to predict the stress distribution inside the cellular domain and thus determine the material strengths and failures at the local level are also discussed.

关键词： architectured material     cellular materials     multi-scale modeling     homogenization method     effective material properties     computational method    

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Gas dynamic characteristic of displacer in Stirling cryocoolers

LIU Xinguang, LIU Dongyu, WANG Yong, WU Yinong

《能源前沿（英文）》 2008年 第2卷 第4期   页码 499-503 doi: 10.1007/s11708-008-0090-6

摘要： Based on the vector analysis of the dynamic characteristic of the displacer in split-type Stirling cryocoolers, experimental study was performed on a 2 W@80 K cooler to uncover the relationship among pressure fluctuation, damped impedance, inherent frequency, cold-tip temperature and the cooling performance. The result shows that the pressure amplitude and phase shift between pressure and displacer motion decrease when the cooling temperature decreases; the dynamic damp of the displacer increases at lower cooling temperature, which results in the increase of pressure drop of the regenerator, the decrease of average pressure of the cold cubage, the decrease of gas dynamic pressure, the decrease of phase shift between pressure and displacer motion, and the displacement of the regenerator and the PV power; at lower cooling temperature, the inherent frequency of the displacer increases because of the augmentation of gas spring constant. And as the inherent frequency is getting closer to the operating frequency, the drive current of the motor decreases; the piston of the compressor affects the displacer by the pressure fluctuation engendered by its motion, and the displacer reacts by changing the mass and momentum distribution to adjust the gas spring constant and the damp coefficient.
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自然对流气体的摆特性及其在传感器中应用

张福学

《中国工程科学》 2002年 第4卷 第8期   页码 50-53

摘要：

根据自然对流气体具有摆的特性，从而提出气体摆新概念。分析了密闭腔中自然对流气体的浮升力，给出浮升力与温度变化的关系式。试验结果表明，与固体摆、液体摆一样，利用气体摆原理亦能检测加速度和倾角。

关键词： 气体的摆特性     倾角传感器     加速度计    

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液体静压支承静态性能新表达式探索

孟心斋,杨建玺,孟昭焱

《中国工程科学》 2002年 第4卷 第5期   页码 63-66

摘要：

文章分析了液体静压支承传统的静态性能表达式存在的严重缺陷及其产生原因，提出了新的静态性能表达式。这种新的静态性能表达式精确地表达了外加载荷与轴承间隙之间的非线性关系，真实地反映了支承的静态性能。新的静态性能通用表达式可表达各种传统节流器与新型可变节流器节流时支承的主要静态性能，很有应用价值。新的静态性能表达式只有一个变量即外加载荷与油垫推力比，故可在支承节流与尺寸参数未确定之前知道支承的主要静态性能，它有利于事先选择与确定支承在应用时的主要性能，为正确应用液体静压支承提供了可靠的技术基础。

关键词： 液体静压支承     传统节流器     新型可变节流器     静态性能    

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Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

《结构与土木工程前沿（英文）》 2014年 第8卷 第1期   页码 69-82 doi: 10.1007/s11709-014-0231-4

摘要： In this the present study, an attempt has been made to evaluate the seismic hazard considering local site effects by carrying out detailed geotechnical site characterization in Babol, Iran. Use of geotechnical data and synthesis of drilling data extracted from the Babol’s subsurface database have enabled authors to determine the geotechnical properties of each site. These data are consisted of twenty five boreholes up to depth of 40 m. Based on the obtained data from geotechnical investigation the study area is divided to five zones. Dynamic analysis was performed in time domain, using fully nonlinear model by PLAXIS. A series of analysis in the study area showed the site period, ranging from 0.4 to 0.8 s. Finally the obtained response spectra from fully nonlinear method were compared with site response spectra of Iran’s 2800 (earthquake) code.

关键词： fully nonlinear method     site effect     dynamic analysis     response spectra    

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A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 359-377 doi: 10.1007/s11709-022-0816-2

摘要： In order to study the bearing performance of a new type of prefabricated subway station structure (PSSS), firstly, a three-dimensional finite element model of the PSSS was established to study the nonlinear mechanics and deformation performance. Secondly, the bearing mechanism of a PSSS was investigated in detail. Finally, the development law of damages to a thin-walled prefabricated component and the failure evolution mechanism of a PSSS were discussed. The results showed that this new type of the PSSS had good bearing capacity. The top arch structure was a three-hinged arch bearing system, and the enclosure structure and the substructure were respectively used as the horizontal and vertical support systems of the three-hinged arch structure to ensure the integrity and stability of the overall structure. Moreover, the tongue-and-groove joints could effectively transmit the internal force between the components and keep the components deformed in harmony. The rigidity degradation of the PSSS caused by the accumulation of damages to the spandrel, hance, arch foot, and enclosure structure was the main reason of its loss of bearing capacity. The existing thin-walled components design had significant advantages in weight reduction, concrete temperature control, components hoisting, transportation and assembly construction, which achieved a good balance between safety, usability and economy.

关键词： prefabricated subway station     thin-walled components     finite element analysis     bearing characteristic     failure mechanism    

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标题 作者 时间 类型 操作

Preload characteristics identification of the piezoelectric-actuated 1-DOF compliant nanopositioning

Ruizhou WANG, Xianmin ZHANG

期刊论文

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

期刊论文

Inverse identification of the mechanical parameters of a pipeline hoop and analysis of the effect of preload

Ye GAO, Wei SUN

期刊论文

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

期刊论文

Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

期刊论文

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

期刊论文

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

期刊论文

Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

Macro-architectured cellular materials: Properties, characteristic modes, and prediction methods

Zheng-Dong MA

期刊论文

Gas dynamic characteristic of displacer in Stirling cryocoolers

LIU Xinguang, LIU Dongyu, WANG Yong, WU Yinong

期刊论文

自然对流气体的摆特性及其在传感器中应用

张福学

期刊论文

液体静压支承静态性能新表达式探索

孟心斋,杨建玺,孟昭焱

期刊论文

Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

期刊论文

A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

期刊论文