检索结果-南通市图书馆

Interactions of p.r.icles with solidifying front in Al_2O_(3p) /Al Si composites

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1999年第3期9卷 524-529页

作者： Wu Shusen(吴树森), Huang Naiyu(黄乃瑜),An ping(安萍) College of Materials Science and engineering, Huazhong University of Science and Technology, Wuhan 430074, p.r. china Huazhong Univ Sci & Technol Coll Mat Sci & Engn Wuhan 430074 Peoples R China

The behavior of ceramic p.r.icles at the solid/liquid interface and the distribution of p.r.icles in metallic matrix composites was studied with a zone unidirectional solidification method. Two kinds of p.r.ice disp.r.ed composites, Al 2O 3p /Al 12.6%Si Sr and Al 2O 3p /Al 12.6%Si Sr Ca containing Al 2O 3 p.r.icles in volume fraction 2%～5% were used. In the Al 2O 3p /Al Si Sr composites, the p.r.icles were pushed by the solidifying front, and did not uniformly distribute in the solid. But in the Al 2O 3p /Al Si Sr Ca composites, the p.r.icles were engulfed by the solidifying front and uniformly distributed in the solid. The p.r.icles engulfing into the solid was realized only by Sr and Ca addition at the same time. As the interfacial energy between solid and p.r.icle was decreased in this case, the Al 2O 3 p.r.icles acted as the substrates of heterogeneous nucleation for the Si phases, which made the p.r.icles to be engulfed.

关键词： metallic matrix composites solidification p.r.icle size distributionDocument code: A

rESEArCH ON STrAIGHTENING TECHNOLOGY CAM SYSTEM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2003年第2期16卷 175-177页

作者： Zhai HuaDep.r.ment of mechanical engineering,Hefei University of Technology,Hefei 230009, china Dep.r.ment of mechanical engineering Hefei University of Technology Hefei 230009

Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straightening technology's database and the model ofstroke-controlled precise straightening calculation model. The op.r.tional test of the CAM systemhas been passed.

关键词： straightening technology calculation model CAM database

Orientation-Singularity representation and Orientation-Capability Computation of a Special Class of the Gough-Stewart p.r.llel Mechanisms Using Unit Quaternion

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2012年第6期25卷 1096-1104页

作者： LI Baokun1, 2, CAO Yi1, 3, *, ZHANG Qiuju1, and HUANG Zhen4 1 School of mechanical engineering, Jiangnan University, Wuxi 214122, china 2 School of mechanical engineering, Anhui University of Science and Technology, Huainan 232001, china 3 State Key Laboratory of Fluid power Transmission and Control, Hangzhou 310027, china 4 robotics research Center, Yanshan University, Qinhuangdao 066004, china 1. School of mechanical engineering Jiangnan University Wuxi 214122 China 2. School of mechanical engineering Anhui University of Science and Technology Huainan 232001 China 3. State Key Laboratory of Fluid power Transmission and Control Hangzhou 310027 China 4. robotics research Center Yanshan University Qinhuangdao 066004 China

Singular configuration seriously affects the p.r.ormance of the Gough-Stewart p.r.llel mechanism and has attracted many researchers’ attentions. However, most of existing topics often focus on the position-singularity of the mechanism for a constant-orientation, but few rep.r.s research the orientation-singularity for a given position. In order to investigate the orientation-singularity of the Gough-Stewart p.r.llel mechanisms with two dissimilar semi-regular hexagonal platforms for a given position, after constructing the discrimination matrix of the singular configuration of the mechanism and computing the determinant of this matrix by using unit quaternion as the orientation p.r.meters which can avoid the singularities in p.r.meterization, a general symbolic expression representing the three-dimensional orientation-singularity locus for a given position is obtained and the three-dimensional view of the orientation-singularity locus is further described. The orientation-singularity-free void exists inside the orientation-singularity locus, but the shape of the orientation-singularity-free void is irregular and inconvenient for the design of the mechanism. The minimal inscribed sphere of the three-dimensional orientation-singularity locus namely the orientation-singularity-free ball is described. The radius of the ball orientation-capability is used as the measurement for the orientation-singularity-free void size. A new efficient algorithm is proposed for the computation of the orientation-capability. Finally, the influences of the geometry p.r.meters and the different positions of the mechanism on the orientation-capability are discussed. A new method of the singularity analysis of the Gough-Stewart p.r.llel mechanism is advanced based on the unit quaternion, and the research finds have imp.r.ant referential value for the configuration p.r.meters optimization of this class of the p.r.llel mechanisms with the goal of having the maximal singularity-free zone.

关键词： p.r.llel mechanism unit quaternion orientation-singularity orientation-singularity-free void orientation-capability

External synchronization of two dynamical systems with uncertain p.r.meters

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第3期53卷 731-740页

作者： HAN QingKai 1,SUN XiaoYu 2,YANG XiaoGuang 3 &WEN BangChun 1 1 School of mechanical engineering&Automation,Northeastern University,Shenyang 110004,china 2 School of Electrical engineering,Shenyang University of Technology,Shenyang 110023,china 3School of mechanical engineering,The University of Birmingham,Birmingham,B15 2TT,UK 1. School of mechanical engineering & Automation Northeastern University Shenyang 110004 China2. School of Electrical Engineering Shenyang University of Technology Shenyang 110023 China3. School of Mechanical Engineering The University of Birmingham Birmingham B15 2TT UK

External synchronization is addressed as two or more dynamical systems with synchronous motions,which is also regarded as master-slave *** this pap.r.two dynamical systems,one employs a hysteretic term to model the friction phenomenon,the other involves a hardening stiffness component with the third order of displacement due to flexible deformation,are controlled to converge to the same *** control strategy is extended from feedback control for all p.r.meters known to adaptive control for linear p.r.meters unknown and all p.r.meters *** slave system can keep synchronous motions with the movements of master via the designed control strategy even all the p.r.meters are not *** stability of synchronization error,the transient process into synchronization and the effects of p.r.meters on the designed controller using different control strategies are *** simulation results unfold the feasibility and effectiveness of this synchronization method.

关键词： controlled synchronization uncertain p.r.meters hysteretic system Duffing system

Quantitative Evaluation for Drawability of Sheet Metal

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第5期21卷 763-766页

作者： Zhiqing XIONG and Xuemei YANGDep.r.ment of mechanical engineering, Nanjing Institute of Technology, Nanjing 210013, china Dep.r.ment of mechanical engineering Nanjing Institute of Technology Nanjing 210013 China

The theoretical evaluating method is given for the drawability of the sheet with normal anisotropy. The general solution on the cracking load of deep-drawing is deduced, which is based on three kinds of hardening curve of materials most in use. The distributions of stress and strain in the deformed region and the drawing force are obtained by the numerical method. The limiting drawing ratio is calculated through computer-aided simulating test. The exp.r.ments of deep-drawing to four kinds of sheet metals express that the relative errors between the predictive and the exp.r.mental results about the cracking load and the limiting drawing ratio are within 5%. The drawability of common sheet metals can be quantitatively evaluated in precise terms by means of the theory and the method advanced in this pap.r.

关键词： Sheet forming Deep-drawing Formability Drawability

An Exp.r. System in Frp Composite Material Design

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第5期17卷 556-560页

作者： Qingfen LI, Zhaoxia CUI and Weimin WANG College of mechanical & Electrical engineering, Harbin engineering University, Harbin 150001, china Jianhua GAO Dep.r.ment of mechanical engineering, Shanghai Jiao Tong University, Shanghai 200030, china Harbin Engn Univ Coll Mech & Elect Engn Harbin 150001 Peoples R China Shanghai Jiao Tong Univ Dept Mech Engn Shanghai 200030 Peoples R China

An exp.r. system prototype for fibre-reinforced plastic matrix (Frp) composite material design, ESFrp, has been developed. The system consists of seven main functional p.r.s: a general inference engine, a set of knowledge bases, a material prop.r.ies algorithm base, an explanation engine, various data bases, several function models and the user interface. The ESFrp can simulate human exp.r.s to make design scheme for fibre-reinforced plastics design, Frp layered plates design and Frp typical engineering components design. It can also predict the material prop.r.ies and make strength analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.

关键词： An Exp.r. System in Frp Composite Material Design Frp

TiC/Fe cermet coating by plasma cladding using asphalt as a carbonaceous precursor

在线全文

学校读者我要写书评

暂无评论

progress in Natural Science:Materials International 2008年第4期18卷 447-454页

作者： Junbo Liu School of mechanical and Electronic engineering, Weifang University, Weifang 261061, china School of mechanical and Electronic engineering Weifang University Weifang 261061 China

A new Ti-Fe-C compound powder for plasma cladding was prep.r.d by heating a mixture powder of ferrotitanium and asphalt p.r.-lyzed as a carbonaceous precursor. The carbon by the p.r.lysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. The TiC/Fe cermet coatings were prep.r.d by plasma cladding with the compound powder. results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem of the reactive constituent p.r.icles being sep- arated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different lam- inated layers:one is the composite layer in which the round fine TiC p.r.icles (re disp.r.ed within a Fe matrix, the other is the p.r.gentic layer of TiC and Ti2O3. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68 ± 5(Hr30N). In the same fretting conditions, the wear area of Ni60 coating is about 11 times as much as the TiC/Fe cermet coating.

关键词： plasma cladding TiC/Fe cermet coating precursor Microstructure Wear resistance

The Effect of Body pitching on Leg-Spring Behavior in Quadruped running

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic engineering 2010年第3期7卷 219-227页

作者： Qi Deng, Shigang Wang, Qinghua Liang, Jinqiu Mo School of mechanical engineering, Shanghai Jiao Tong University, Shanghai 200240 p. r. china [a] School of mechanical engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China

In this pap.r.we investigated how the running speed would affect the dynamics of body pitching, and whether body inertiais imp.r.ant for animals. passive trotting of spring-mass model and passive bounding of spring-beam model were studied atdifferent speeds for different sets of body p.r.meters respectively. Furthermore, different body inertias were used in *** found that running speed exerts effect on leg p.r.ormance by means of centrifugal force. The centrifugal force can be understoodas an enhancement to the natural frequency of the spring-mass system. The disadvantage of body pitching may beoffset by the great increase in centrifugal force at high speed. The results also reveal that body mass distribution might not be themain reason for the difference in maximal running speeds of different animals.

关键词： body pitching leg p.r.ormance running speed centrifugal force body inertia

Optimal guaranteed cost control for fuzzy descriptor systems with time-varying delay

在线全文

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 2008年第3期19卷 584-591页

作者： Tian Weihua1,2 & Zhang Huaguang3 1. School of Information Science and engineering, Northeastern Univ., Shenyang 110004, p. r. china 2. Dept. of Automatic Control, Shenyang Inst. of engineering, Shenyang 110136, p. r. china 3. School of Information Science and engineering, Northeastern Univ., Shenyang 110004, p. r. china. (received December 27, 2006) [a]School of Information Science and engineering Northeastern Univ. Shenyang 110004 p. r. china [b]Dept. of Automatic Control Shenyang Inst. of engineering Shenyang 110136 p. r. china [c]School of Information Science and engineering Northeastern Univ. Shenyang 110004 p. r. china

Based on the delay-independent rule, the problem of optimal guaranteed cost control for a class of Takagi-Sugeno （T-S） fuzzy descriptor systems with time-varying delay is studied. A linear quadratic cost function is considered as the p.r.ormance index of the closed-loop system. Sufficient conditions for the existence of guaranteed cost controllers via state feedback are given in terms of linear matrix inequalities （LMIs）, and the design of an optimal guaranteed cost controller can be reduced to a convex optimization problem. It is shown that the designed controller not only guarantees the asymptotic stability of the closed-loop fuzzy descriptor delay system, but also provides an optimized upp.r.bound of the guaranteed cost. At last, a numerical example is given to illustrate the effectiveness of the proposed method and the p.r.ect p.r.ormance of the optimal guaranteed cost controller.

关键词： fuzzy descriptor systems optimal guaranteed cost control time-varying delay linear matrix inequalities (LMIs).