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Topology optimization based on reduction methods with applications to multiscale design and additive manufacturing

Emmanuel TROMME, Atsushi KAWAMOTO, James K. GUEST

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 151-165 doi: 10.1007/s11465-019-0564-8

摘要: Advanced manufacturing processes such as additive manufacturing offer now the capability to control material placement at unprecedented length scales and thereby dramatically open up the design space. This includes the considerations of new component topologies as well as the architecture of material within a topology offering new paths to creating lighter and more efficient structures. Topology optimization is an ideal tool for navigating this multiscale design problem and leveraging the capabilities of advanced manufacturing technologies. However, the resulting design problem is computationally challenging as very fine discretizations are needed to capture all micro-structural details. In this paper, a method based on reduction techniques is proposed to perform efficiently topology optimization at multiple scales. This method solves the design problem without length scale separation, i.e., without iterating between the two scales. Ergo, connectivity between space-varying micro-structures is naturally ensured. Several design problems for various types of micro-structural periodicity are performed to illustrate the method, including applications to infill patterns in additive manufacturing.

关键词: multiscale topology optimization     micro-structure     additive manufacturing     reduction techniques     substructuring     static condensation     super-element    

Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assisted

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1268-1280 doi: 10.1007/s11705-022-2143-5

摘要: The micro-nano composite structure can endow separation membranes with special surface properties, but it often has the problems of inefficient preparation process and poor structural stability. In this work, a novel atomization-assisted nonsolvent induced phase separation method, which is also highly efficient and very simple, has been developed. By using this method, a bicontinuous porous microfiltration membrane with robust micro-nano composite structure was obtained via commercially available polymers of polyacrylonitrile and polyvinylpyrrolidone. The formation mechanism of the micro-nano composite structure was proposed. The microphase separation of polyacrylonitrile and polyvinylpyrrolidone components during the atomization pretreatment process and the hydrogen bonding between polyacrylonitrile and polyvinylpyrrolidone molecules should have resulted in the nano-protrusions on the membrane skeleton. The membrane exhibits superhydrophilicity in air and superoleophobicity underwater. The membrane can separate both surfactant-free and surfactant-stabilized oil-in-water emulsions with high separation efficiency and permeation flux. With excellent antifouling property and robust microstructure, the membrane can easily be recycled for long-term separation. Furthermore, the scale-up verification from laboratory preparation to continuous production has been achieved. The simple, efficient, cost-effective preparation method and excellent membrane properties indicate the great potential of the developed membranes in practical applications.

关键词: atomization     nonsolvent induced phase separation     bicontinuous porous structure     micro-nano composite structure     oil-water separation    

Photocatalytic activity of ZnO films with micro-grid structure

Chunzhi LI , Wenwen WANG , Junying ZHANG , Hailing ZHU , Weiwei ZHANG , Tianmin WANG ,

《环境科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 289-293 doi: 10.1007/s11783-009-0034-3

摘要: A layer of zinc oxide (ZnO) micro-grid was deposited on the surface of ZnO film using the DC reactive magnetron sputtering method and the micro-sphere lithography technique on glass substrates. Samples of this layer were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and ultraviolet-visible light spectroscopy. X-ray diffraction showed the high crystallinity of ZnO film and the regular arrangement of the micro-grid. The micro-grid ZnO has a lower specular reflection and a higher diffuse reflection, allowing incident light to reflect two or three times to enhance the usage of light. Photocatalytic degradation experiments on methylene blue using both ZnO micro-grid and ordinary film showed that the ZnO micro-grid has better photocatalytic properties than ordinary film. The ZnO micro-grid enhanced the photocatalytic efficiency of ZnO film by 28% with a degradation time of 300min.

关键词: Photocatalysis     ZnO micro-grid     polystyrene latex spheres template     diffuse reflection    

一种新型转子式陀螺的分辨率为0.47″的转子微偏转角度检测方法 Article

Hai LI, Xiao-wei LIU, Rui WENG, Hai-feng ZHANG

《信息与电子工程前沿(英文)》 2017年 第18卷 第5期   页码 591-598 doi: 10.1631/FITEE.1500454

摘要: 差分电容检测被广泛应用于振动陀螺仪质量块的位移测量,然而由于结构、理论以及接口电路等因素的限制其在转子式陀螺所需的转子偏转角度检测方面还尚未取得较高分辨率。本文提出了一种差分电容检测结构,用以测量一种新型转子式陀螺转子的偏转角度。本文建立了结构电容与转子偏转角度之间关系的数学模型,分析了差分电容与结构参数之间的关系,并获得了初步优化的尺寸参数。设计了一款低噪声读出接口电路将差分电容的变化转换为电压信号。对陀螺仪的转台测试结果表明,该角度检测结构的最小可分辨的偏转角度小于0.47″(0.00013°),三次多项式补偿后检测结构的非线性可达0.33%,并可进一步提高。结果表明该检测结构和电路有助于实现该陀螺仪的高精度。

关键词: 微角度检测;差分电容结构;转子式陀螺    

利用微机电系统技术制作弯曲结构表面无线无源柔性加速度计 Research Article

李晨1,2,贾蔓谷1,洪应平2,薛亚楠2,熊继军2

《信息与电子工程前沿(英文)》 2022年 第23卷 第5期   页码 801-809 doi: 10.1631/FITEE.2100236

摘要: 提出一种LC无线无源柔性加速度计,解决测量弯曲结构表面加速度的困难。 该加速度计由柔性聚酰亚胺(PI)衬底和平面螺旋电感(厚度为300 nm)组成,采用微机电系统(MEMS)技术,可任意弯曲或折叠,可牢固地粘附在具有弯曲结构的物体表面。利用射频无线传输原理,通过改变加速度计与天线之间的距离来测量加速度信号。与带导线的加速度计相比,该加速度计可以防止导线在振动过程中脱落,从而延长其使用寿命。通过搭建实验平台,当天线与加速度计之间的距离为5 mm时,在弯曲结构表面展示了加速度计在20至100 m/s2加速度下的传感能力。结果表明,加速度和峰峰值输出电压接近线性,加速度计灵敏度高达0.27 mV/(m•s−2)。此外,该加速度计的最大误差小于0.037%。

关键词: 弯曲结构表面;柔性加速度计;微机电系统(MEMS)技术;无线非接触式测量    

Flexible micro flow sensor for micro aerial vehicles

Rong ZHU, Ruiyi QUE, Peng LIU

《机械工程前沿(英文)》 2017年 第12卷 第4期   页码 539-545 doi: 10.1007/s11465-017-0427-0

摘要:

This article summarizes our studies on micro flow sensors fabricated on a flexible polyimide circuit board by a low-cost hybrid process of thin-film deposition and circuit printing. The micro flow sensor has merits of flexibility, structural simplicity, easy integrability with circuits, and good sensing performance. The sensor, which adheres to an object surface, can detect the surface flow around the object. In our study, we install the fabricated micro flow sensors on micro aerial vehicles (MAVs) to detect the surface flow variation around the aircraft wing and deduce the aerodynamic parameters of the MAVs in flight. Wind tunnel experiments using the sensors integrated with the MAVs are also conducted.

关键词: micro flow sensor     flexible sensor     surface flow sensing     aerodynamic parameter     micro aerial vehicle (MAV)    

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 146-149 doi: 10.1007/s11465-013-0260-z

摘要:

To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm . It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.

关键词: Micro-Electro-Mechanical Systems (MEMS)     micro accelerometer     force-balanced micro accelerometer     frequency     error sensitivity    

Numerical simulation of micro scale flowing and boiling

Wen WANG, Rui ZHUAN,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 396-401 doi: 10.1007/s11708-009-0049-2

摘要: Numerical simulations of flowing and boiling in micro channels are presented, including the modeling of bubble dynamics of nucleate boiling, and a description of the interface of two phases with the volume-of-fluid (VOF). The two calculated cases are compared with related experimental data in literature. Some simulated results are found corresponding well to the experimental data. The simulated results also show the details of 3-dimensional heat transfer and the flow in micro channels, which are helpful to the investigation of the mechanism of two-phase heat transfer and flow in micro channels.

关键词: volume-of-fluid (VOF)     micro channel     nucleate boiling     bubble dynamics     simulation    

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

《机械工程前沿(英文)》 2007年 第2卷 第4期   页码 433-438 doi: 10.1007/s11465-007-0074-y

摘要: This paper develops a 30 mm × 30 mm × 50 mm spherical micro actuator driven by piezoelectric ceramic stacks (PZT), and analyzes its dynamic performances. First, the space coordinate relationship of the spherical micro actuator and a dynamic model are set up. Second, The Runge-Kutta arithmetic is used to calculate the dynamical parameters of the micro actuator; the SIMULINK module of MATLAB is used to build the dynamical simulating model and then simulate it. Third, an experimental sample of the spherical micro actuator is developed, a micromanipulator is integrated with a micro-gripper based on the sample spherical micro actuator, and the experimental research on the micro assembly is conducted between a micro shaft of 180 μm and a micro spindle sleeve of 200 μm. Finally, the characteristics of the spherical micro actuator influenced by the mass of the metal sphere of the micro actuator, driving signal frequency, friction coefficient of the contact surface between the metal sphere and the friction block of the micro driving unit are analyzed. The experimental results indicate that the rotation resolution of the micro actuator reaches 0.000 1°, the rotation positioning precision reaches 0.000 5°, and the maximum working frequency is about 1200 Hz. The experimental results validate the back rotation vibration model of the spherical micro actuator. The micromanipulator integrated by the spherical micro actuator can meet the requirements of precise micro operation and assembly for micro electro mechanical systems (MEMS) or other microelements in micro degree fields.

关键词: spherical     micro-gripper     friction coefficient     dynamic     frequency    

Laboratory assessment of Alaska aggregates using Micro-Deval test

Jenny LIU,Sheng ZHAO,Anthony MULLIN

《结构与土木工程前沿(英文)》 2017年 第11卷 第1期   页码 27-34 doi: 10.1007/s11709-016-0359-5

摘要: Aggregates suitable for use in asphalt concrete (AC) pavement construction must meet durability criteria. Thus, it is critical to select appropriate tests to properly characterize aggregate durability. In Alaska, durability tests currently being used for aggregates in AC pavement include Los Angeles (LA) abrasion test, sulfate soundness test and Washington degradation test. However, there have long been concerns arising over Washington degradation test used as an acceptance tool, motivating pavement practitioners to seek more suitable alternatives. This paper presents a study to investigate the feasibility of using Micro-Deval test, commonly used in other states, to evaluate the durability of Alaskan aggregates in AC pavement as well as its potential to replace Washington degradation test. Micro-Deval test, Washington degradation test and other tests currently specified in Alaska were conducted on aggregates from 16 batches representing statewide sources. Based on the testing results, it is found that using Micro-Deval test for durability assessment of Alaska aggregates was feasible and reproducible, and a high potential was revealed to use Micro-Deval test to replace Washington degradation test in Alaska. It is recommended that Micro-Deval test be considered as an additional test for a certain period, but in the long run should be used along with current LA abrasion and sulfate soundness tests to provide a more desirable durability assessment of Alaska aggregates used in AC pavement.

关键词: aggregate durability     Washington degradation test     Micro-Deval test    

Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 58-64 doi: 10.1007/s11705-009-0106-8

摘要: This paper presents an experimental investigation of a novel impinging stream reactor (ISR) with the aim of high mixing intensity. The integral mixing quality in the reactor was measured with the iodide-iodate reaction and showed excellent mixing performance. The impact of the operating parameters, such as fluxes, circulation and inter-nozzle distances, was investigated in terms of segregation index. The results showed that the increase of flux, the decrease of inter-nozzle distance and a suitable circulation can improve the micro-mixing efficiency. Based on turbulence theory, it was estimated that the characteristic micro-mixing time was 0.002—0.02 s, which was much shorter than that in the stirred tank reactor. The micro-mixing time was related to the segregation index, which was in good agreement with those in the literature.

关键词: micro-mixing     impinging streams reactor     turbulent mixing     mass transfer    

Recent advances in micro- and nano-machining technologies

Shang GAO, Han HUANG

《机械工程前沿(英文)》 2017年 第12卷 第1期   页码 18-32 doi: 10.1007/s11465-017-0410-9

摘要:

Device miniaturization is an emerging advanced technology in the 21st century. The miniaturization of devices in different fields requires production of micro- and nano-scale components. The features of these components range from the sub-micron to a few hundred microns with high tolerance to many engineering materials. These fields mainly include optics, electronics, medicine, bio-technology, communications, and avionics. This paper reviewed the recent advances in micro- and nano-machining technologies, including micro-cutting, micro-electrical-discharge machining, laser micro-machining, and focused ion beam machining. The four machining technologies were also compared in terms of machining efficiency, workpiece materials being machined, minimum feature size, maximum aspect ratio, and surface finish.

关键词: micro machining     cutting     electro discharge machining (EDM)     laser machining     focused ion beam (FIB)    

Special issue: Micro-electromechanical systems (MEMS)

Zhuangde JIANG

《机械工程前沿(英文)》 2017年 第12卷 第4期   页码 457-458 doi: 10.1007/s11465-017-0492-4

microbial fuel cell for enhancing the nitrogen removal of the anammox process coupled with iron-carbon micro-electrolysis

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1409-3

摘要:

• MFC promoted the nitrogen removal of anammox with Fe-C micro-electrolysis.

关键词: Waste tire     MFCs     Micro-electrolysis     Anammox     Feammox    

Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

ZHANG Xiaoyan, ZHANG Xingqun, CHEN Yunguang, YUAN Xiuling

《能源前沿(英文)》 2008年 第2卷 第4期   页码 489-493 doi: 10.1007/s11708-008-0110-6

摘要: Based on experimental results of ternary non-azeotropic refrigerant mixture R417A flowing and boiling in one smooth and two internally grooved horizontal tubes with different geometrical parameters, a boiling heat transfer correlations was developed for refrigerant mixtures flowing inside micro-fin tubes by applying the enhancement factor in the present modified-Kattan model which was modified by the experimental data of R417A in a smooth tube. The comparison between the calculation and the experimental results indicates that the prediction by the present correlations is in good agreement with the experiment of refrigerant mixtures inside different micro-fin tubes with a standard deviation of ± 30% for vapor qualities below 80%.

关键词: comparison     micro-fin     calculation     transfer     prediction    

标题 作者 时间 类型 操作

Topology optimization based on reduction methods with applications to multiscale design and additive manufacturing

Emmanuel TROMME, Atsushi KAWAMOTO, James K. GUEST

期刊论文

Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assisted

期刊论文

Photocatalytic activity of ZnO films with micro-grid structure

Chunzhi LI , Wenwen WANG , Junying ZHANG , Hailing ZHU , Weiwei ZHANG , Tianmin WANG ,

期刊论文

一种新型转子式陀螺的分辨率为0.47″的转子微偏转角度检测方法

Hai LI, Xiao-wei LIU, Rui WENG, Hai-feng ZHANG

期刊论文

利用微机电系统技术制作弯曲结构表面无线无源柔性加速度计

李晨1,2,贾蔓谷1,洪应平2,薛亚楠2,熊继军2

期刊论文

Flexible micro flow sensor for micro aerial vehicles

Rong ZHU, Ruiyi QUE, Peng LIU

期刊论文

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

期刊论文

Numerical simulation of micro scale flowing and boiling

Wen WANG, Rui ZHUAN,

期刊论文

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

期刊论文

Laboratory assessment of Alaska aggregates using Micro-Deval test

Jenny LIU,Sheng ZHAO,Anthony MULLIN

期刊论文

Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

期刊论文

Recent advances in micro- and nano-machining technologies

Shang GAO, Han HUANG

期刊论文

Special issue: Micro-electromechanical systems (MEMS)

Zhuangde JIANG

期刊论文

microbial fuel cell for enhancing the nitrogen removal of the anammox process coupled with iron-carbon micro-electrolysis

期刊论文

Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

ZHANG Xiaoyan, ZHANG Xingqun, CHEN Yunguang, YUAN Xiuling

期刊论文