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Comprehensive analysis of the influence of structural and dynamic parameters on the accuracy of nano-precision

Chengyuan LIANG, Fang YUAN, Xuedong CHEN, Wei JIANG, Lizhan ZENG, Xin LUO

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 255-272 doi: 10.1007/s11465-019-0538-x

摘要： Nano-precision positioning stages are characterized by rigid-flexible coupling systems. The complex dynamic characteristics of mechanical structure of a stage, which are determined by structural and dynamic parameters, exert a serious influence on the accuracy of its motion and measurement. Systematic evaluation of such influence is essential for the design and improvement of stages. A systematic approach to modeling the dynamic accuracy of a nano-precision positioning stage is developed in this work by integrating a multi-rigid-body dynamic model of the mechanical system and measurement system models. The influence of structural and dynamic parameters, including aerostatic bearing configurations, motion plane errors, foundation vibrations, and positions of the acting points of driving forces, on dynamic accuracy is investigated by adopting the H-type configured stage as an example. The approach is programmed and integrated into a software framework that supports the dynamic design of nano-precision positioning stages. The software framework is then applied to the design of a nano-precision positioning stage used in a packaging lithography machine.

关键词： nano-precision positioning stage     analysis and design     structural and dynamic parameters     dynamic accuracy     systematic modeling    

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XB高精度火箭橇试验滑轨

杨兴邦

《中国工程科学》 2000年 第2卷 第10期   页码 98-104

摘要：

火箭橇试验滑轨是一种大型地面动态模拟试验设备，用于研究试验件在空中高速度、高加速度运行时所遇到的诸多技术问题，其技术核心是一百万分之一的轨道直线性相对精度。它要求具有稳定的滑轨基础、高直线度准直基准线和光滑平顺的钢轨作为基本条件，需要采用钢轨精密机械加工、钢轨焊接、焊缝超声波探伤、轨道张拉锚固锁定、轨道直线度调整等新工艺技术。我国已成功地建成世界上唯一的、钢轨经精密机械加工后再全程焊接的XB高精度火箭橇试验滑轨。文章论述了它的诞生背景、设计思路、技术方案、技术与建造特点以及应用展望，该滑轨直线度达到世界先进水平。

关键词： 火箭滑橇     试验滑轨     地面动态模拟试验    

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Reliability analysis of kinematic accuracy for the elastic slider-crank mechanism

TUO Yaofei, CHEN Jianjun, ZHANG Chijiang, CHEN Yongqin

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 214-217 doi: 10.1007/s11465-007-0037-3

摘要： This paper deals with the static and dynamic output kinematic accuracy of a group of elastic slider-crank mechanisms with the same design parameters by taking the bar length, the joint-gaps, the mass density, and the sectional and the physical parameters as random variables. According to the principle of linear pile-up of small displacement, the static and dynamic output kinematic errors are synthesized, and the reliability model of the kinematic accuracy of the mechanism is built. Through an example, a study of the influencing factors on the reliability of the output kinematic accuracy of the mechanism is made. The results obtained reveal the following facts: with the increase of the crank s rotating speed, the dynamic elastic deformation of the mechanism becomes the principal factor that greatly affects the reliability of the output kinematic accuracy of the mechanism.

关键词： output kinematic     group     slider-crank     kinematic accuracy     displacement    

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A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0688-0

摘要： The use of artificial intelligence to process sensor data and predict the dimensional accuracy of machined parts is of great interest to the manufacturing community and can facilitate the intelligent production of many key engineering components. In this study, we develop a predictive model of the dimensional accuracy for precision milling of thin-walled structural components. The aim is to classify three typical features of a structural component—squares, slots, and holes—into various categories based on their dimensional errors (i.e., “high precision,” “pass,” and “unqualified”). Two different types of classification schemes have been considered in this study: those that perform feature extraction by using the convolutional neural networks and those based on an explicit feature extraction procedure. The classification accuracy of the popular machine learning methods has been evaluated in comparison with the proposed deep learning model. Based on the experimental data collected during the milling experiments, the proposed model proved to be capable of predicting dimensional accuracy using cutting parameters (i.e., “static features”) and cutting-force data (i.e., “dynamic features”). The average classification accuracy obtained using the proposed deep learning model was 9.55% higher than the best machine learning algorithm considered in this paper. Moreover, the robustness of the hybrid model has been studied by considering the white Gaussian and coherent noises. Hence, the proposed hybrid model provides an efficient way of fusing different sources of process data and can be adopted for prediction of the machining quality in noisy environments.

关键词： precision milling     dimensional accuracy     cutting force     convolutional neural networks     coherent noise    

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Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Guangbo HAO,Haiyang LI,Suzen KEMALCAN,Guimin CHEN,Jingjun YU

《机械工程前沿（英文）》 2016年 第11卷 第2期   页码 129-134 doi: 10.1007/s11465-016-0392-z

摘要：

In order to accurately model compliant mechanism utilizing plate flexures, qualitative planar stress (Young’s modulus) and planar strain (plate modulus) assumptions are not feasible. This paper investigates a quantitative equivalent modulus using nonlinear finite element analysis (FEA) to reflect coupled factors in affecting the modelling accuracy of two typical distributed-compliance mechanisms. It has been shown that all parameters have influences on the equivalent modulus with different degrees; that the presence of large load-stiffening effect makes the equivalent modulus significantly deviate from the planar assumptions in two ideal scenarios; and that a plate modulus assumption is more reasonable for a very large out-of-plane thickness if the beam length is large.

关键词： coupling factors     modelling accuracy     compliant mechanisms     equivalent modulus    

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Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

《工程管理前沿（英文）》 2018年 第5卷 第2期   页码 195-201 doi: 10.15302/J-FEM-2017052

摘要： In this work, we examine the impact of crude distillation unit (CDU) model errors on the results of refinery-wide optimization for production planning or feedstock selection. We compare the swing cut+ bias CDU model with a recently developed hybrid CDU model (Fu et al., 2016). The hybrid CDU model computes material and energy balances, as well as product true boiling point (TBP) curves and bulk properties (e.g., sulfur % and cetane index, and other properties). Product TBP curves are predicted with an average error of 0.5% against rigorous simulation curves. Case studies of optimal operation computed using a planning model that is based on the swing cut+ bias CDU model and using a planning model that incorporates the hybrid CDU model are presented. Our results show that significant economic benefits can be obtained using accurate CDU models in refinery production planning.

关键词： impact of model accuracy on production planning     swing cut+ bias CDU model     hybrid CDU model     refinery feedstock selection optimization     optimization of refinery operation    

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Surface accuracy optimization of mechanical parts with multiple circular holes for additive manufacturing

Jinghua XU, Hongsheng SHENG, Shuyou ZHANG, Jianrong TAN, Jinlian DENG

《机械工程前沿（英文）》 2021年 第16卷 第1期   页码 133-150 doi: 10.1007/s11465-020-0610-6

摘要： Surface accuracy directly affects the surface quality and performance of mechanical parts. Circular hole, especially spatial non-planar hole set is the typical feature and working surface of mechanical parts. Compared with traditional machining methods, additive manufacturing (AM) technology can decrease the surface accuracy errors of circular holes during fabrication. However, an accuracy error may still exist on the surface of circular holes fabricated by AM due to the influence of staircase effect. This study proposes a surface accuracy optimization approach for mechanical parts with multiple circular holes for AM based on triangular fuzzy number (TFN). First, the feature lines on the manifold mesh are extracted using the dihedral angle method and normal tensor voting to detect the circular holes. Second, the optimal AM part build orientation is determined using the genetic algorithm to optimize the surface accuracy of the circular holes by minimizing the weighted volumetric error of the part. Third, the corresponding weights of the circular holes are calculated with the TFN analytic hierarchy process in accordance with the surface accuracy requirements. Lastly, an improved adaptive slicing algorithm is utilized to reduce the entire build time while maintaining the forming surface accuracy of the circular holes using digital twins via virtual printing. The effectiveness of the proposed approach is experimentally validated using two mechanical models.

关键词： surface accuracy optimization     multiple circular holes     additive manufacturing (AM)     part build orientation     triangular fuzzy number (TFN)     digital twins    

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A feasibility study of the measuring accuracy and capability of wireless sensor networks in tunnel monitoring

Xiaojun LI, Zhong JI, Hehua ZHU, Chen GU

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 111-120 doi: 10.1007/s11709-012-0150-1

摘要： Fire disasters and the deterioration of tunnel structures are major concerns for tunnel operation and maintenance. Traditional wired monitoring systems have many drawbacks in terms of installation time, overall cost, and flexibility in tunnel environments. In recent years, there has been growing interest in the use of wireless sensor networks (WSNs) for the monitoring of various structural monitoring applications. This paper evaluated the feasibility of applying a WSN in the monitoring of tunnels. The monitoring requirements of tunnels under explosion and combustion fire scenarios are analyzed using numerical simulation, and the maximum possible distance for temperature sensors is derived. The displacement monitoring of tunnels using an inclinometer is investigated. It is recommended that the inclinometer should be installed in the 1/4 span of the tunnel structure. The maximum wireless transmission distances in both outdoor and tunnel environments were examined. The influences of surface materials and sensor node locations on the data transmission distance in tunnel environments were also investigated. The experimental results show that the data loss in tunnel environments is approximately three times that in outdoor environments. Surface material has a considerable influence on the transmission distance of radio signals. The distance is 25 ? 28 m for a raw concrete surface, 20 m for a brick surface, and 36 m for a terrazzo surface. The transmission distances along the middle of quarter points are approximately 0.9 ( is the transmission distance in the center of the tunnel), and the relative error is less than±3%. The transmission distances at different locations along the bottom exhibit significant differences, decreasing from the middle to the corner point, with distances of approximately 0.8 at the quarter points and minimum distances of approximately 0.55 at the corner points.

关键词： wireless sensor network (WSN)     tunnel     monitoring     feasibility study    

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Precision control system of two-DOF stage with linear ultrasonic motor

ZHANG Hanlei, SHI Yunlai, ZHAO Chunsheng

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 421-425 doi: 10.1007/s11465-008-0063-9

摘要： Using an appropriate control method, linear ultrasonic motors can be used in applications requiring high position accuracy. In this paper, a closed loop PI control system is designed to achieve high position accuracy during the control of a two-DOF stage driven by linear ultrasonic motors. Two ultrasonic motors are mounted on the stage to generate motion in two orthogonal directions. The PI control algorithm is used to increase the stability and accuracy of position control. The -axis mover covers 30 mm forward and backward in less than 0.3 s settling time and the -axis mover in less than 0.4 s. Experimental results denote that the control strategy proposed in this paper appears to have high efficiency, quick response, and high accuracy.

关键词： settling     position accuracy     PI control     control algorithm     orthogonal    

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XFEM schemes for level set based structural optimization

Li LI, Michael Yu WANG, Peng WEI

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 335-356 doi: 10.1007/s11465-012-0351-2

摘要：

In this paper, some elegant extended finite element method (XFEM) schemes for level set method structural optimization are proposed. Firstly, two- dimension (2D) and three-dimension (3D) XFEM schemes with partition integral method are developed and numerical examples are employed to evaluate their accuracy, which indicate that an accurate analysis result can be obtained on the structural boundary. Furthermore, the methods for improving the computational accuracy and efficiency of XFEM are studied, which include the XFEM integral scheme without quadrature sub-cells and higher order element XFEM scheme. Numerical examples show that the XFEM scheme without quadrature sub-cells can yield similar accuracy of structural analysis while prominently reducing the time cost and that higher order XFEM elements can improve the computational accuracy of structural analysis in the boundary elements, but the time cost is increasing. Therefore, the balance of time cost between FE system scale and the order of element needs to be discussed. Finally, the reliability and advantages of the proposed XFEM schemes are illustrated with several 2D and 3D mean compliance minimization examples that are widely used in the recent literature of structural topology optimization. All numerical results demonstrate that the proposed XFEM is a promising structural analysis approach for structural optimization with the level set method.

关键词： structural optimization     level set method     extended finite element method (XFEM)     computational accuracy and efficiency    

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Ion beam figuring of continuous phase plates based on the frequency filtering process

Mingjin XU,Yifan DAI,Xuhui XIE,Lin ZHOU,Shengyi LI,Wenqiang PENG

《机械工程前沿（英文）》 2017年 第12卷 第1期   页码 110-115 doi: 10.1007/s11465-017-0430-5

摘要：

Ion beam figuring (IBF) technology is an effective technique for fabricating continuous phase plates (CPPs) with small feature structures. This study proposes a multi-pass IBF approach with different beam diameters based on the frequency filtering method to improve the machining accuracy and efficiency of CPPs during IBF. We present the selection principle of the frequency filtering method, which incorporates different removal functions that maximize material removal over the topographical frequencies being imprinted. Large removal functions are used early in the fabrication to figure the surface profile with low frequency. Small removal functions are used to perform final topographical correction with higher frequency and larger surface gradient. A high-precision surface can be obtained as long as the filtering frequency is suitably selected. This method maximizes the high removal efficiency of the large removal function and the high corrective capability of the small removal function. Consequently, the fast convergence of the machining accuracy and efficiency can be achieved.

关键词： ion beam figuring (IBF)     continuous phase plates (CPPs)     machining accuracy     machining efficiency     frequency filtering process    

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Facebook Deepfake 检测挑战赛

Ramin Skibba

《工程（英文）》 2020年 第6卷 第12期   页码 1339-1340 doi: 10.1016/j.eng.2020.10.008

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Numerical analysis of nonlinear dynamic behavior of earth dams

Babak EBRAHIMIAN

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 24-40 doi: 10.1007/s11709-010-0082-6

摘要： A numerical study is conducted to investigate the dynamic behavior of earth dams. The numerical investigation employs a fully nonlinear dynamic finite difference analysis incorporating a simple elastic perfectly plastic constitutive model to describe the stress-strain response of the soil and the Rayleigh damping to increase the level of hysteretic damping. The extended Masing rules are implemented into the constitutive model to explain more accurately the soil response under general cyclic loading. The soil stiffness and hysteretic damping change with loading history. The procedures for calibrating the constructed numerical model with centrifuge test data and also a real case history are explained. For the latter, the Long Valley (LV) earth dam subjected to the 1980 Mammoth Lake earthquake as a real case-history is analyzed and the obtained numerical results are compared with the real measurements at the site in both the time and frequency domains. Relatively good agreement is observed between computed and measured quantities. It seems that the Masing rules combined with a simple elasto-plastic model gives reasonable numerical predictions. Afterwards, a comprehensive parametric study is carried out to identify the effects of dam height, input motion characteristics, soil behavior, strength of the shell materials and dam reservoir condition on the dynamic response of earth dams. Three real earthquake records with different levels and peak acceleration values (PGAs) are used as input motions. The results show that the crest acceleration decreases when the dam height increases and no amplification is observed. Further, more inelastic behavior and more earthquake energy absorption are observed in higher dams.

关键词： earth dam     numerical     nonlinear response     dynamic analysis     earthquake     dam height    

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Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1372-1388 doi: 10.1007/s11705-023-2302-3

摘要： Lignin is the largest natural aromatic biopolymer, but usually treated as industrial biomass waste. The development of lignin/polymer biocomposites can promote the high value utilization of lignin and the greening of polymers. However, the weak interfacial interaction between industrial lignin and polymer induces poor compatibility and serious agglomeration in polymer owing to the strong intermolecular force of lignin. As such, it is extremely difficult to prepare high performance lignin/polymer biocomposites. Recently, we proposed the strategy of in situ construction of interfacial dynamic bonds in lignin/polymer composites. By taking advantage of the abundant oxygen-containing polar groups of lignin, we inserted dynamic bonding connection such as hydrogen bonds and coordination bonds into the interphase between lignin and the polymer matrix to improve the interfacial interactions. Meanwhile, the natural amphiphilic structure characteristics of lignin were utilized to construct the hierarchical nanophase separation structure in lignin/polymer composites. The persistent problems of poor dispersity and interfacial compatibility of lignin in the polymer matrix were effectively solved. The lignin-modified polymer composites achieved simultaneously enhanced strength and toughness. This concise review systematically summarized the recent research progress of our group toward building high-performance lignin/polymer biocomposites through the design of interfacial dynamic bonds (hydrogen bonds, coordination bonds, and dynamic covalent bonds) between lignin and different polymer systems (polar plastics, rubber, polyurethane, hydrogels, and other polymers). Finally, the future development direction, main challenges, and potential solutions of lignin application in polymers were presented.

关键词： lignin     polymer     interfacial dynamic bonds    

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Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 250-256 doi: 10.1007/s11705-009-0281-7

摘要： Two kinds of heavy oils were fractionated into eight fractions by Liquid-Solid Adsorption Chromatography, respectively, and samples were collected to measure properties. According to the elemental analysis, molecular weight and H-NMR data, average molecular structures of polycyclic aromatic and heavy resin were constructed with improved Brown-Ladner (B-L) method and several corrections. And then, the most stable conformations of polycyclic aromatic and heavy resin in vacuum and toluene solution were obtained by molecular dynamic simulation, and the molecular size was gotten via the radius of gyration analysis. The results showed that the radius of gyration of polycyclic aromatic and heavy resin was 0.55–0.70 nm in vacuum and 0.60–0.90 nm in toluene solution. With molecular weight increasing, the molecular size in vacuum and toluene solution also increased. Due to the swelling behavior of solvent, the alkyl side chains of heavy oil molecule in solution were more stretched. Thus, the molecular size in toluene solution was larger than that in vacuum.

关键词： dynamic simulation     molecular dynamic     behavior     molecule     Adsorption Chromatography    

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标题 作者 时间 类型 操作

Comprehensive analysis of the influence of structural and dynamic parameters on the accuracy of nano-precision

Chengyuan LIANG, Fang YUAN, Xuedong CHEN, Wei JIANG, Lizhan ZENG, Xin LUO

期刊论文

XB高精度火箭橇试验滑轨

杨兴邦

期刊论文

Reliability analysis of kinematic accuracy for the elastic slider-crank mechanism

TUO Yaofei, CHEN Jianjun, ZHANG Chijiang, CHEN Yongqin

期刊论文

A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

期刊论文

Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Guangbo HAO,Haiyang LI,Suzen KEMALCAN,Guimin CHEN,Jingjun YU

期刊论文

Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

期刊论文

Surface accuracy optimization of mechanical parts with multiple circular holes for additive manufacturing

Jinghua XU, Hongsheng SHENG, Shuyou ZHANG, Jianrong TAN, Jinlian DENG

期刊论文

A feasibility study of the measuring accuracy and capability of wireless sensor networks in tunnel monitoring

Xiaojun LI, Zhong JI, Hehua ZHU, Chen GU

期刊论文

Precision control system of two-DOF stage with linear ultrasonic motor

ZHANG Hanlei, SHI Yunlai, ZHAO Chunsheng

期刊论文

XFEM schemes for level set based structural optimization

Li LI, Michael Yu WANG, Peng WEI

期刊论文

Ion beam figuring of continuous phase plates based on the frequency filtering process

Mingjin XU,Yifan DAI,Xuhui XIE,Lin ZHOU,Shengyi LI,Wenqiang PENG

期刊论文

Facebook Deepfake 检测挑战赛

Ramin Skibba

期刊论文

Numerical analysis of nonlinear dynamic behavior of earth dams

Babak EBRAHIMIAN

期刊论文

Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

期刊论文

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

期刊论文