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净味剂对SBS改性沥青存储稳定性影响及净味效果评价

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上海公路 2024年第2期 147-152,I0014页

作者：彭芳玉叶奋新疆大学建筑工程学院新疆乌鲁木齐830047 同济大学道路与交通工程教育部重点实验室上海201804

为研究两种类型净味剂在不同掺量下对不同类型SBS改性沥青长期存储稳定性的影响和净味效果,找出两者间的关联性,对净味SBS改性沥青进行三大指标试验和离析试验,并评价其净味效果。结果表明:净味改性沥青的三大指标均能满足规范要求。两... 详细信息

为研究两种类型净味剂在不同掺量下对不同类型SBS改性沥青长期存储稳定性的影响和净味效果,找出两者间的关联性,对净味SBS改性沥青进行三大指标试验和离析试验,并评价其净味效果。结果表明:净味改性沥青的三大指标均能满足规范要求。两种净味剂均能提高SBS改性沥青的存储稳定性,且粉末净味剂的效果更佳。两种净味剂都能使H_(2)S、NO、CO三种气体的浓度和沥青烟的质量有所降低,但液体净味剂的整体效果更出色。两种净味剂在II型改性沥青中,净味效果优于在I型改性沥青中。在不同的实验条件下,两种净味剂均在相同的掺量下达到最佳效果。故在实际应用中,推荐液体净味剂的掺量为0.005%,粉末净味剂的掺量为0.05%。

关键词：道路工程存储稳定性离析试验净味改性沥青净味剂

初始残余应力的检测方法及其在薄壁叶片加工变形分析中的应用研究

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Transactions of Nanjing University of Aeronautics and Astronautics 2024年第2期41卷 158-173页

作者：张华赵晟强孙豪彭芳瑜闫蓉唐小卫单玉楠华中科技大学机械科学与工程学院国家数控系统工程研究中心中国武汉430074 华中科技大学机械科学与工程学院数字化制造装备与技术国家重点实验室中国武汉430074

薄壁叶片是航空发动机的关键部件,在加工过程中极易发生剧烈的变形。已有的变形研究控制重点关注在减小切削力和加工残余应力(Machining‑induced residual stress,MIRS)这两方面。本文利用材料热处理和锻造过程中产生的初始残余应力(Ini... 详细信息

薄壁叶片是航空发动机的关键部件,在加工过程中极易发生剧烈的变形。已有的变形研究控制重点关注在减小切削力和加工残余应力(Machining‑induced residual stress,MIRS)这两方面。本文利用材料热处理和锻造过程中产生的初始残余应力(Initial residual stress,IRS)来减轻薄壁零件受切削力与加工残余应力影响所产生的变形。由于初始残余应力测量困难且具有破坏性,本文提出了一种初始残余应力逆辨识方法来测量Ti6Al4V的初始残余应力。与传统的初始残余应力测量方法相比,逆辨识方法更符合应力分布和叶片变形的分布趋势。为了研究和解耦初始残余应力、加工残余应力和切削力之间对加工变形影响的相互作用,针对钛合金直纹叶片为对象进行实验验证,并建立了有限元预测模型。在分析切削力与加工残余应力对变形的影响后,可以得到切削力占变形程度的46.17%,平均值为26.36μm,而加工残余应力占变形程度的53.83%,平均值为30.70μm。耦合初始残余应力后使得整体的变形减小,受加工残余应力影响的最大挠度变形从35.32μm降低到15.50μm,该分析为利用初始残余应力减小薄壁叶片加工变形提供了新的方法。

关键词：薄壁叶片加工变形残余应力分析切削力模型

Anisotropic Force Ellipsoid Based Multi-axis Motion Optimization of Machine Tools

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 960-967页

作者： peng fangyu YAN Rong CHEN Wei YANG Jianzhong LI Bin State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430074 China National NC System Engineering Research Center Huazhong University of Science and Technology Wuhan 430074 China

The existing research of the motion optimization of multi-axis machine tools is mainly based on geometric and kinematic constraints, which aim at obtaining minimum-time trajectories and finding obstacle-free paths. In motion optimization, the stiffness characteristics of the whole machining system, including machine tool and cutter, are not considered. The paper presents a new method to establish a general stiffness model of multi-axis machining system. An analytical stiffness model is established by Jacobi and point transformation matrix method. Based on the stiffness model, feed-direction stiffness index is calculated by the intersection of force ellipsoid and the cutting feed direction at the cutter tip. The stiffness index can help analyze the stiffness performance of the whole machining system in the available workspace. Based on the analysis of the stiffness performance, multi-axis motion optimization along tool paths is accomplished by mixed programming using Matlab and Visual C＋＋. The effectiveness of the motion optimization method is verified by the experimental research about the machining performance of a 7-axis 5-linkage machine tool. The proposed research showed that machining stability and production efficiency can be improved by multi-axis motion optimization based on the anisotropic force ellipsoid of the whole machining system.

关键词： stiffness force ellipsoid multi-axis motion optimization

Influence mechanism of machining angles on force induced error and their selection in five axis bullnose end milling

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Chinese Journal of Aeronautics 2020年第12期33卷 3447-3459页

作者： Zerun ZHU fangyu peng Rong YAN Zepeng LI Jiawei WU Xiaowei TANG Chen CHEN School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

In the machining of complicated surfaces,the cutters with large length/diameter ratios are used widely and the deformation of the machining system is one of the principal error *** the process planning stage,the cutting direction angle,the cutter lead and tilt angles are usually optimized to minimize the force induced *** may lead to a low machining efficiency for bullnose end mills,as the material removal rates are different largely for different machining *** this paper,the influence mechanism of the machining angles on the force induced error is studied based on the models of the instantaneous cutting force when the cutter flute traveling through the cutting contact point and the stiffness of the machining *** order to evaluate the machining angles,the force induced error/efficiency indicator(FEI)is defined as the division of the force induced error and the equal volume sphere of the removed *** is dimensionless,with the lower FEI,the lower force induced error and the higher machining *** optimal selection of the machining angles,the critical FEI is calculated with the constraint of force induced error and the desired material removal rate,and the critical FEI separate the set of the machining angles into two *** the feed rate scheduling process,the machining angles in the optimal subset would have higher machining accuracy and efficiency,while the machining angles in the other subset have lower machining accuracy and *** the machining experiment of five axis machining and freeform surface machining,the effectiveness and superiority of the proposed FEI method is verified with a bullnose end mill,which can improve the machining efficiency with the constraint of force induced error.

关键词： Force induced error Five axis machining Machining efficiency Machining angles Milling Optimization

On-line chatter detection using servo motor current signal in turning

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Science China(Technological Sciences) 2011年第12期54卷 3119-3129页

作者： LIU HongQil CHEN QmgHa LI Bin MAO XinYong MAO KuanMin peng fangyu National NC System Engineering Research Center Huazhong University of Science ＆Technology Wuhan 430074 China State Key Laboratory of Digital Manufacturing Equipment ＆ Technology Huazhong University of Science ＆Technology Wuhan 430074 China

Chatter often poses limiting factors on the achievable productivity and is very harmful to machining processes. In order to avoid effectively the harm of cutting chatter,a method of cutting state monitoring based on feed motor current signal is proposed for chatter identification before it has been fully developed. A new data analysis technique,the empirical mode decomposition(EMD),is used to decompose motor current signal into many intrinsic mode functions(IMF) . Some IMF's energy and kurtosis regularly change during the development of the chatter. These IMFs can reflect subtle mutations in current signal. Therefore,the energy index and kurtosis index are used for chatter detection based on those IMFs. Acceleration signal of tool as reference is used to compare with the results from current signal. A support vector machine(SVM) is designed for pattern classification based on the feature vector constituted by energy index and kurtosis index. The intelligent chatter detection system composed of the feature extraction and the SVM has an accuracy rate of above 95% for the identification of cutting state after being trained by experimental data. The results show that it is feasible to monitor and predict the emergence of chatter behavior in machining by using motor current signal.

关键词： chatter detection current signal empirical mode decomposition (EMD) support vector machine (SVM)

Intelligent learning model-based skill learning and strategy optimization in robot grinding and polishing

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Science China(Technological Sciences) 2022年第9期65卷 1957-1974页

作者： CHEN Chen WANG Yu GAO ZhiTao peng fangyu TANG XiaoWei YAN Rong ZHANG YuKui School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

With the rapid advancement of manufacturing in China,robot machining technology has become a popular research *** increasing number of robots are currently being used to perform complex tasks during manual operation,e.g.,the grinding of large components using multi-robot systems and robot teleoperation in dangerous environments,and machining conditions have evolved from a single open mode to a multisystem closed *** the environment is constantly changing with multiple systems interacting with each other,traditional methods,such as mechanism modeling and programming are no longer *** learning models,such as deep learning,transfer learning,reinforcement learning,and imitation learning,have been widely used;thus,skill learning and strategy optimization have become the focus of research on robot *** learning in robot machining can use robotic flexibility to learn skills under unknown working conditions,and machining strategy research can optimize processing quality under complex working ***,skill learning and strategy optimization combined with an intelligent learning model demonstrate excellent performance for data characteristics learning,multisystem transformation,and environment perception,thus compensating for the shortcomings of the traditional research *** paper summarizes the state-of-the-art in skill learning and strategy optimization research from the perspectives of feature processing,skill learning,strategy,and model optimization of robot grinding and polishing,in which deep learning,transfer learning,reinforcement learning,and imitation learning models are integrated into skill learning and strategy optimization during robot grinding and ***,this paper describes future development trends in skill learning and strategy optimization based on an intelligent learning model in the system knowledge transfer and nonstructural environment autonomous processing.

关键词： learning model robot grinding polishing feature processing skill learning strategy optimization

High precision and efficiency robotic milling of complex parts:Challenges,approaches and trends

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Chinese Journal of Aeronautics 2022年第2期35卷 22-46页

作者： Zerun ZHU Xiaowei TANG Chen CHEN fangyu peng Rong YAN Lin ZHOU Zepeng LI Jiawei WU School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Wuhan Digital Design and Manufacturing Innovation Centre Co. Ltd.Wuhan 430074China

Due to the advantages of large workspace,low cost and the integrated vision/force sensing,robotic milling has become an important way for machining of complex *** recent years,many scholars have studied the problems existing in the applications of robotic milling,and lots of results have been made in the dynamics,pose planning,deformation control etc.,which provides theoretical guidance for high precision and high efficiency of robotic *** the perspective of complex parts robotic milling,this paper focuses on machining process planning and control techniques including the analysis of the robot-workspace,robot trajectory planning,vibration monitoring and control,deformation monitoring and *** well as the principles of these technologies such as robot stiffness characteristics,dynamic characteristics,chatter mechanisms,and deformation *** methods and characteristics related to the theory and technology of robotic milling of complex parts are summarized *** latest research progress and achievements in the relevant fields are *** is hoped that the challenges,strategies and development related to robotic milling could be clarified through the carding work in this paper,so as to promote the application of related theories and technologies in high efficiency and precision intelligent milling with robot for complex parts.

关键词： Complex parts Deformation Dynamics Robotic milling Stiffness Vibration control

Variable eccentric distance-based tool path generation for orthogonal turn-milling

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Frontiers of Mechanical Engineering 2015年第4期10卷 352-366页

作者： fangyu peng Wei WANG Rong YAN Xianyin DUAN Bin LI State Key Laboratory of Digital Manufacturing Equipment andTechnology School of Mechanical Science and Engineering HuazhongUniversity of Science and Technology Wuhan 430074 China National Numerical Control System Engineering Research Center Huazhong University of Science and Technology Wuhan 430074 China

This study proposes an algorithm for max- imizing strip width in orthogonal tum-miUing based on variable eccentric distance. The machining error model is first established based on the local cutting profile at the contact line. The influencing factors of the strip width are then investigated to analyze their features and determine an optimizing strategy. The optimized model for maximum machining strip width is formulated by adopting a variable eccentric distance. Hausdorff distance and Fr6chet distance are introduced in this study to implement the constraint function of the machining error in the optimized model. The computing procedure is subsequently provided. Simulations and experiments have been conducted to verify the effectiveness of the proposed algorithm.

关键词： orthogonal turn-milling variable eccentricdistance local cutting profile machining strip-widthmaximization

Large-scale identification of potential phase-separation proteins from plants using a cell-free system

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Molecular Plant 2023年第2期16卷 310-313页

作者： Honghong Zhang fangyu peng Chun He Yan Liu Haiteng Deng Xiaofeng Fang Center for Plant Biology School of Life SciencesTsinghua UniversityBejing 100084China MOE Key Laboratory of Bioinformatics School of Life SciencesTsinghua UniversityBeijing100084China

Dear Editor,Biomolecular condensates have emerged as key players in cellular processes and responses to stress(Alberti and Hyman,2021).Recent studies have revealed that most biomolecular condensates arise from liquid-liquid phase separation(Banani et al.,2017;Shin and Brangwynne,2017),a process that has been described in the field of polymer chemistry.

关键词： chemistry. separation phase