检索结果-南通市图书馆

Journal of Magnesium and Alloys 2022年第2期10卷 530-538页

作者： Koji Hagihara Kosuke Miyoshi Division of Materials and Manufacturing Science Graduate School of EngineeringOsaka University2-1YamadaokaSuitaOsaka 565-0871Japan Department of Adaptive machine Systems Graduate School of EngineeringOsaka University2-1 YamadaokaSuitaOsaka 565-0871Japan Department of Physical Science and engineering Nagoya Institute of TechnologyNagoya 466-8555Japan

For the development of high-strength Mg alloys,active use of Laves phases such as C14-type Mg_(2)Yb and Mg_(2)Ca is strongly ***,the brittleness of the Laves phases is the biggest obstacle to *** first found that kink-band formation can be induced in directionally solidified Mg/Mg_(2)Yb and Mg/Mg_(2)Ca eutectic lamellar alloys when a stress is applied parallel to the lamellar interface,leading to a high yield stress accompanied with *** is,microstructural control can induce a new deformation mode that is not activated in the constituent phases,thereby inducing *** was clarified that the geometric relationship between the operative slip plane in the constituent phases and the lamellar interface,and the microstructural features that provide kink-band nucleation sites are important factors for controlling kink-band *** obtained results show a possibility to open the new door for the development of novel high-strength structural material using the kink bands.

关键词： Deformation kink band Lamellar microstructure Laves phase Magnesium alloys Mechanical properties

CPS Modeling of CNC machine Tool Work Processes Using an Instruction-Domain Based Approach

在线全文

学校读者我要写书评

暂无评论

engineering 2015年第2期1卷 247-260页

作者： Jihong Chen Jianzhong Yang Huicheng Zhou Hua Xiang Zhihong Zhu Yesong Li Chen-Han Lee Guangda Xu National Numerical control System engineering Research Center Huazhong University of Science and Technology

Building cyber-physical system(CPS) models of machine tools is a key technology for intelligent manufacturing. The massive electronic data from a computer numerical control(CNC) system during the work processes of a CNC machine tool is the main source of the big data on which a CPS model is established. In this work-process model, a method based on instruction domain is applied to analyze the electronic big data, and a quantitative description of the numerical control(NC) processes is built according to the G code of the processes. Utilizing the instruction domain, a work-process CPS model is established on the basis of the accurate, real-time mapping of the manufacturing tasks, resources, and status of the CNC machine tool. Using such models, case studies are conducted on intelligent-machining applications, such as the optimization of NC processing parameters and the health assurance of CNC machine tools.

关键词： cyber-physical system (CPS) big data computer numerical control (CNC) machine tool electronic data of work processes instruction domain intelligent machining

Modeling of Transient Thermal Conditions in Cutting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mechanics engineering and Automation 2017年第3期7卷 113-119页

作者： T. Augspurger F. Klocke B. Dobbeler M. Brockmann S. Gierlings A. Lima Laboratory for machine tools and Production engineering R WTHAachen University Aachen 52056 Germany Fraunhofer institute for Production Technology IPT R WTH Aachen University Aachen 52074 Germany

The thermal conditions like the temperature distribution and the heat fluxes during metal cutting have a major influence on the machinability, the tool lifetime, the metallurgical structure and thus the functionality of the work piece. This in particular applies for manufacturing processes like milling, drilling and turning for high-value turbomachinery components like impellers, combustion engines and compressors of the aerospace and automotive industry as well as energy generation, which play a major role in modern societies. However, numerous analytical and experimental efforts have been conducted in order to understand the thermal conditions in metal cutting, yet many questions still prevail. Most models are based on a stationary point of view and do not include time dependent effects like in intensity and distribution varying heat sources, varying engagement conditions and progressive tool wear. In order to cover such transient physics an analytical approach based on Green＇s functions for the solution of the partial differential equations of unsteady heat conduction in solids is used to model entire transient temperature fields. The validation of the model is carried out in orthogonal cutting experiments not only punctually but also for entire temperature fields. For these experiments an integrated measurement of prevailing cutting force and temperature fields in the tool and the chip by means of high-speed thermography were applied. The thermal images were analyzed with regard to thermodynamic energy balancing in order to derive the heat partition between tool, chips and workpiece. The thus calculated heat flow into the tool was subsequently used in order to analytically model the transient volumetric temperature fields in the tool. The described methodology enables the modeling of the transient thermal state in the cutting zone and particular in the tool, which is directly linked to phenomena like tool wear and workpiece surface modifications.

关键词： Metal cutting infrared thermography heat sources transient temperature fields model based on Green's functions.

Theoretical and Experimental Research on Error Analysis and Optimization of Tool Path in Fabricating Aspheric Compound Eyes by Precision Micro Milling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical engineering 2014年第3期27卷 558-566页

作者： CHEN Mingjun XIAO Yong TIAN Wenlan WU Chunya CHU Xin Center for Precision engineering Harbin institute of technology

Structure design and fabricating methods of three-dimensional （3D） artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes （ACEs） are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye （ACE） with surface roughness （Ra） below 0.12 p.m is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.

关键词： aspheric compound eyes (ACEs) micro milling tool path optimization

Stability analysis of a thin-walled cylinder in turning operation using the semi-discretization method

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第2期30卷 214-222页

作者： Arnab Chanda Achim Fischer Peter Eberhard Santosha Kumar Dwivedy institute of engineering and Computational Mechanics University of Stuttgart

In this work, the stability of a flexible thin cylindrical workpiece in turning is analyzed. A process model is derived based on a finite element representation of the workpiece flexibility and a nonlinear cutting force law. Repeated cutting of the same surface due to overlapping cuts is modeled with the help of a time delay. The stability of the so obtained system of periodic delay differential equations is then determined using an approximation as a time-discrete system and Floquet theory. The time-discrete system is obtained using the semi-discretization method. The method is implemented to analyze the stability of two different workpiece models of different thicknesses for different tool positions with respect to the jaw end. It is shown that the stability chart depends on the tool position as well as on the thickness.

关键词： machine tools Stability Chatter

Containment consensus with measurement noises and time-varying communication delays

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第2期24卷 23-29页

作者：周峰王正杰范宁军 School of Electromechanical engineering Beijing Institute of Technology

In this paper,we consider the containment consensus control problem for multi-agent systems with measurement noises and time-varying communication delays under directed *** using stochastic analysis tools and algebraic graph theory,we prove that the followers can converge to the convex hull spanned by the leaders in the sense of mean square if the allowed upper bound of the time-varying delays satisfies a certain sufficient ***,the time-varying delays are asymmetric for each follower agent,and the time-delay-dependent consensus condition is ***,numerical simulations are provided to illustrate the effectiveness of the obtained theoretical results.

关键词： multi-agent systems containment consensus noise communication delays

Silver-integrated EDM processing of TiAl6V4 implant material has antibacterial capacity while optimizing osseointegration

在线全文

学校读者我要写书评

暂无评论

Bioactive Materials 2024年第1期31卷 497-508页

作者： Hilmar Büssemaker Ann-Kathrin Meinshausen Viet Duc Bui Joachim Döring Vadym Voropai Adrian Buchholz Andreas J.Mueller Karsten Harnisch André Martin Thomas Berger Andreas Schubert Jessica Bertrand Department of Orthopaedic Surgery Otto-von-Guericke University MagdeburgGermany Professorship Micromanufacturing Technology Chemnitz University of TechnologyChemnitzGermany institute of Molecular and Clinical Immunology Otto-von-Guericke University MagdeburgGermany Health Campus Immunology Infectiology and InflammationOtto-von-Guericke University MagdeburgMagdeburgGermany institute of Materials and Joining Technology Otto-von-Guericke UniversityMagdeburgGermany Fraunhofer institute for machine tools and Forming Technology ChemnitzGermany

Periprosthetic joint infections(PJI)are a common reason for orthopedic revision *** has been shown that the silver surface modification of a titanium alloy(Ti-6Al-4V)by PMEDM(powder mixed electrical discharge machining)exhibits an antibacterial effect on Staphylococcus *** the thickness of the silver-modified surface influences the adhesion and proliferation of bacteria as well as the ossification processes and in-vivo antibacterial capacity has not been investigated ***,the aim of this work is to investigate the antibacterial effect as well as the in vitro ossification process depending on the thickness of PMEDM silver modified *** attachment of *** on the PMEDM modified surfaces was significantly lower than on comparative control samples,independently of the tested surface *** proliferation,however,was not affected by the silver content in the surface *** observed a long-term effect of antibacterial capacity in vitro,as well as in *** induction of ROS,as indicator for oxidative stress,was observed in the bacteria,but not in osteoblast-like *** influence on the in vitro osteoblast function was observed,whereas osteoclast formation was drastically reduced on the silver *** changes in cell death,the metabolic activity and oxidative stress was measured in *** show that already small amounts of silver exhibit a significant antibacterial capacity while not influencing the osteoblast ***,PMEDM using silver nano-powder admixed to the dielectric represents a promising technology to shape and concurrently modify implant surfaces to reduce infections while at the same time optimizing bone ingrowth of endoprosthesis.

关键词： alloy silver powder

KD(D&K) and Double-Bases Cooperating Mechanism

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 1999年第2期10卷 48-54页

作者： Yang Bingru(School of information engineering,University of Science and Technology of BeiJing,100083, P. R. China)Xiong Fanlun(The institute of Intelligent machine, Academic Sinica,Hefei 230031, P. R. China) School of Information engineering University of Science and Technology of Beijing 100083 P. R. China The institute of Intelligent machine Academic Sinica Hefei 230031 P. R. China

KD(D&K) (Synthesized Knowledge Discovery System based on Database and KnowledgeBase Cooperating Mechanism) is first advanced in this paper on the basis of KDD (KnowledgeDiscovery System based on Database) and KDK (Knowledge Discovery System based on KnowledgeBase). KD (D&K) is not simple addition of KDD and KDK but a new system with absolutelynew character and essential development, which is distinct from KDD and KDK and includes *** only the generalized structural frame of control rules KD (D&K) acquiring method is proposed,but also the theoretical basis of its key technical problem--don ble-bases cooperating mechanism isdiscussed according to the original academic idea to restrict KDD by basic knowledge base.

关键词： Knowledge discovery General structure Cooperating mechanism.

High Speed Machining for Linear Paths Blended with G3 Continuous Pythagorean-Hodograph Curves

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2022年第4期35卷 1586-1607页

作者： ZHAO Kai LI Shurong College of control Science and engineering China University of Petroleum(East China)Qingdao266580China College of Computer Science and Information engineering Anyang Institute of TechnologyAnyang455000China School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China

Previously,many studies have illustrated corner blend problem with different parameter *** a few of them take a Pythagorean-hodograph(PH)curve as the transition arc,let alone corresponding real-time interpolation *** this paper,an integrated corner-transition mixing-interpolation-based scheme(ICMS)is proposed,considering transition error and machine tool ***,the ICMS smooths the sharp corners in a linear path through blending the linear path with G3 continuous PH transition *** obtain optimal PH transition curves globally,the problem of corner smoothing is formulated as an optimization problem with *** order to improve optimization efficiency,the transition error constraint is deduced analytically,so is the curvature extreme of each transition *** being blended with PH transition curves,a linear path has become a blend ***,the ICMS adopts a novel mixed interpolator to process this kind of blend curves by considering machine tool *** mixed interpolator can not only implement jerk-limited feedrate scheduling with critical points detection,but also realize self-switching of two interpolation ***,two patterns are machined with a carving platform based on *** l results show the effectiveness of ICMS.

关键词： Bézier control polygon corner transition jerk-limited scheduling mixed interpolation pythagorean-hodograph curve

Impact Damage Identification of Aluminum Alloy Reinforced Plate Based on GWO-ELM Algorithm

在线全文

学校读者我要写书评

暂无评论

Structural Durability & Health Monitoring 2023年第6期17卷 485-500页

作者： Wei Li Benjian Zou Yuxiang Luo Ning Yang Faye Zhang Mingshun Jiang Lei Jia School of control Science and engineering Shandong UniversityJinan250061China Communication Technology Division Shandong Institute of Space Electronic TechnologyYantai264000China

As a critical structure of aerospace equipment,aluminum alloy stiffened plate will influence the stability of spacecraft in orbit and the normal operation of the *** this study,a GWO-ELM algorithm-based impact damage identification method is proposed for aluminum alloy stiffened panels to monitor and evaluate the damage condition of such stiffened panels of ***,together with numerical simulation,the experimental simulation to obtain the damage acoustic emission signals of aluminum alloy reinforced panels is performed,to establish the damage ***,the amplitude-frequency characteristics of impact damage signals are extracted and put into an extreme learning machine(ELM)model to identify the impact location and damage degree,and the Gray Wolf Optimization(GWO)algorithm is employed to update the weight parameters of the ***,experiments are conducted on the irregular aluminum alloy stiffened plate with the size of 2200 mm×500 mm×10 mm,the identification accuracy of impact position and damage degree is 98.90% and 99.55% in 68 test areas,*** experiments with ELM and backpropagation neural networks(BPNN)demonstrate that the impact damage identification of aluminum alloy stiffened plate based on GWO-ELM algorithm can serve as an effective way to monitor spacecraft structural damage.

关键词： GWO-ELM aluminum alloy stiffened plate damage identification amplitude-frequency characteristic