毕业论文外文翻译-材料制备机械设计理论中的新趋势和新问题.doc

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1、New Trends and Problems in Material Processing Machine Design Theory WANG Ai-lun ,DUAN Ji-an ,HUANG Ming-hui ,ZHONG Jue(College of Mechanical & Electronic Engineering ,Central South University ,Changsha 410083 ,Hunan China)Abstract : Based on reviewing the historical background, prospecting for the

2、development trend ,analyzing the complicacy and mechanism and summing up some achievements and experiences in scientific research , several new problems and the possible direction of development in material processing technology and machine are proposed ,such as ,producing new concept materials poss

3、essing some specific and extraovdinary properties by means of integrating and coalescing conelative frontier science and technology ;and thereafter a brief discussion is given.Keywords: interface; extraordinary physical field; procession machine ; function material1The Time Background of Material Pr

4、ocessing MachineIn the long span of history of human progress ,many tools ,machines and methods were created and a variety of materials with different properties were processed. Materials and its processing have become one of pillar and driving force of mankind progress. In pace with multi - polar c

5、ompetition in current world and peoples striving perseveringly for happier life ,material function goes beyond unceasingly mens knowledge and imagination ,for example ,cryptic function material ,semiconductor material ,energy material ,vibration - absorptive material , super - strength aluminum allo

6、y accounting for 70 percent of application of aeronautics and space ,metal foil of 45m ,deep drawing plate with anisotropy below 1 percent ,electronic aluminum foil with micro - orientation up to 95 percent ,heat resisting aluminum alloy with super strong specific strength used in aeronautics ,space

7、 and deep sea ,etc. Thus several important development trends with distinct time features in material processing domain are shaped up as follows : (1) Creating material processing machine with extraordinary physical field for processing material with special texture structures and functions. For exa

8、mple ,applications of thermal energy and mechanical energy are breaking through unceasingly technology limit ,and some non - tradition energy ,such as microwave ,chemical energy , bioenergy , etc. , are introduced into material processing procedure one after another ,so that some material processing

9、 machines with extraordinary energy circumstance are produced. (2) Breaking through traditional physical limits and integrating melting ,solidifying ,plastic deformation and heat treatment to obtain special function of material and cut down expenses3 . For example ,near - net shaping material proces

10、sing technology , such as fast rolling , spraying deposition ,over - plastic molding , injection molding , high energy beam ,etc ,is applied. (3) Material processing process is forged ahead in the direction of high speed ,heavy - duty and high accuracy online control ,for instance , the rolling spee

11、d goes up to 130 ms - 1 ,the deformation pressure rises up to 300 MPa ,accuracy of dimension up to 0.1m ,accuracy of shape up to 0. 1 I ,strength accuracy comes up to 0.1 MPa. For these reasons ,it is necessary for material processing machine design theory to integrate and coalesce ingeniously corre

12、lative frontier science and technology to create and produce some new concept material processing machine with following functions.2Due Functions of New Concept Material Processing Machine (1) To have the ability to produce and bear extraordinary physical field and transmit extraordinary energy flow

13、 with the aim of providing extraordinary physical circumstances necessary for new concept material processing. For example ,high gradient temperature field with the speed of cool - down of work interface which exceeds 104106 Ks - 1 , line wave and pulse complex exerted in solidifying - deforming are

14、a , super - strength contact stress field of material forming interface ,turbulent flow field of molten metal with very big flakiness ratio ,low frequency magnetic field with random frequency ,microwave field for powder metal heating ,ultrasonic field for large volume solidifying ,etc. 4 ,are applie

15、d. (2) To have the ability to work in critical state so that high stability and ideal performance of processing machine is ensured under the circumstance of reinforced technological condition and multi - field coupling operation. For example ,chatter suppressing capability of fast ultra - thin rolli

16、ng under the condition of boundary lubricating state5 ,the capability of self - excited vibration suppressing under the condition of special friction state ,synergism stability and disturbance stability of flexible connecting parallel shaft with multi - driving system ,etc. 4 ,are ensured. (3) To ha

17、ve the ability to accurately control the material processing in order to obtain low loss ,high efficiency and high quality of material processing. For example , super - high accuracy on - line monitor of products form ,on line monitor and on - line adjustment of products texture and properties ,prec

18、ision coordination control of multi - procedure , on - line monitor of micro - orientation of metal plastic deformation ,etc. 4 ,are ensured. Some products accuracy index may be enumerated as follows : dimensional accuracy coming to 0.1m , microstructure uniformity to crystal lattice ,strength error

19、 to 0.1 MPa ,etc. 4 In short ,only by new concept material processing machine with extraordinary function being designed and made , can special function material be processed.3 Science Problems and Study Contents of Metal Material Processing MachineUnder the Circumstance of Extraordinary Physical Fi

20、eldIn view of these facts and background mentioned above ,several new research topics can be advanced as follows.3. 1 Coupling Heat Transfer Mechanism of Multi - Phase Interface Temperature - Stress FieldA brand - new microstructure can be obtained through continuously large deformation and fast sol

21、idifying when melting metal is in critical state of liquid solid. At this very moment ,high density heat flow and dynamic heat resistance are present in material processing circumstance . A basic theory problem of designing this kind of machine is to study mechanism of heat transmittance and energy

22、conversion ,and to establish mathematical model .3. 2 Friction Constraint Mechanism of Plastic Flow Interface of Material Processing MachineThe coupling between operation mechanism and workpiece is very complicated because plastic flow is present in processing interface. The interface state , determ

23、ined by velocity , load thermodynamic process , elasticity of operation mechanism ,plasticity of workpiece ,dynamic behaviour of interface sticking - sliding and partial hydrodynamic lubrication ,etc ,affect and form friction constraints mechanism peculiar to material processing machine ,because the

24、se constraints present strong non - linearity ;and under certain circumstances ,the constraints may be destroyed or mismatched instantaneously and thus dynamic instability is resulted in. Thus following problems can be put forward : Mechanism of“spectre chatter”arose from sticking - sliding friction

25、 and partial hydrodynamic lubrication in rolling interface , instability condition and mechanism of constraint between smooth surface and rotating body under the circumstance of high speed ,heavy - duty and boundary lubrication , Lubrication film absorption mechanism and physical chemistry behaviour

26、 of interface of unceasingly regenerative surface ,the relationship between rheological characteristic and machine operation parameters.3. 3 Multi - Body Non - Linear Contact Mechanism Under the Condition of Extra - High Pressure FieldTo build the super strength pressure field on large area is one o

27、f basic function of material processing machine , and it is also necessary to form by once large - size structure element (such as spacecraft , intercontinental vehicles ,car and large - scale aeroplane etc) . The ability to build super strong pressure field is one of important feature and the base

28、of independent national defense. Under the circumstance of super strength pressure field ,multi - body strong nonhertz contact and non - linear friction will be produced ,thus local permanent deformation and degrading of element accuracy may be led. New theory foundation of design of machine with su

29、per strength pressure field will be furnished through study of multi - body strong non - hertz contact mechanism , multi - body non - linear friction mechanism (such as providing force - displacement mixed solving process of three - dimension multi - body) .3. 4 Load Distribution Law in Multi - Slid

30、ing Pair With Structure Bias LoadWith regard to statically indeterminate structure ,load distribution of constraint point is determined by deformation compatibility condition. However ,concerning some plane large - size statically indeterminate structure with sliding degree of freedom in third dimen

31、sion ,load distribution can not be determined by deformation compatibility condition. Thus new theory basis will be provided by analyzing of contact behaviour and mechanism of sliding pair (such as creep ,force of friction ,integral deformation compatibility condition ,etc) .3. 5 Coupling Mechanism

32、and Stability of Multi - Physical Fields in Material Processing SystemsIn the wake of system function becoming more and more diversified , conventional technology limits in material processing machine is being broke through unceasingly ,system structure also becomes increasingly complicated ,and sys

33、tem performance becomes increasingly multi - causal . For example ,any instantaneous state of roller in fast rolling mills is affected by elastic deformation ,plastic flow ,heat transfer process , hydro - dynamic lubrication process ,interface physical chemistry molecular state and so on . In additi

34、on ,electromechanical coupling in processing system have already gone beyond conventional concept ,for instance ,some singular point phenomenon (such as micro - variable can be transformed into macro - variable) ,are present ,thus roller operation instability may be led by perturbation8 . Therefore

35、,this subject will study the interaction mechanism of multi - physical field and the influence on processing system stability and processing material quality started with analysis of micro - state of executive body.3. 6 Multi - Technology Integration and Coalescence of Accurate ControlThe material p

36、rocessing machine ,which operate under the circumstance of extraordinary physical field ,is a complicated large - scale system ,and some parameters of the system vary on feasible field boundary ;thereby ,to keep under accurate control and adjustment of multi field circumstance ,multi - dimension coo

37、rdination ,multi - energy conversion , multi - level information transfer ,interface multi - process coupling ,etc. is of much significance. Since a variety of multi - interaction exists in control model ,it is necessary to establish integration framework of coordination work according to decoupling

38、 of control model ,so as to accurate control based on the multi - technology integration and coalescence is realized.3. 7 Quasi - Reality Design and Concurrent Design Based on Knowledge Innovation SystemsDigitalization and visualization of material processing technology will promote immediately the

39、quality of design, operation and control . Therefore optimization of material processing technology and material processing machine by means of realization of virtual simulation of processing procedure through quasi - reality design and concurrent design is one of our pressing study subjects.3. 8 Me

40、chanical Behavior of Special Function Materials in the Extraordinary Physical FieldMany key elements and parts in material processing machine are often under the circumstance of super strong force field ,temperature field ,electronic magnetic field and flow field ,and must have the functions of cons

41、tructing special physical interface. However ,it is difficult for common single - substance material such as metal ,ceramic polymer ,etc. to have both high index of single property and excellent overall quality. Therefore we need to use certain material with new functions for key position9 ,for inst

42、ance ,multi - dimension function gradient material with ultrahigh physical property ,multi - dimension function gradient material with intelligence. For these reasons ,it is necessary to study basic law and mechanism of these kind of function material mentioned above ,for instance ,stress (strain) d

43、istribution function ,failure mechanism and design criteria of material under the circumstance of extraordinary physical field ,static (dynamic) stiffness and damping ,digitalization design and visualization design of processing system made of gradient function material ,etc ,so that the general mec

44、hanics law of element which is under the circumstance of extraordinary physical field and made of anisotropy multi - dimension gradient function material is obtained. Nowadays ,material processing science and technology is forging rapidly ahead. A forward - looking study aiming at key technology pro

45、blem of material processing machine will provide theory and technology reserve for manufacturing science and industry of 21st century.材料制备机械设计理论中的新趋势和新问题王艾伦,段吉安,黄明辉,钟 掘(中南大学机电工程学院,湖南长沙 410083)摘 要: 在全面综述材料制备机械技术及设备发展动态的基础上,提出了研究领域的几个新问题和发展方向,如通过集成和融合现代相关前沿科学和技术，生产具有超常和特殊性能的新概念材料等,并进行了简要分析和讨论.关键词:界面;超

46、常物理场;制备机械;功能材料1机械材料加工的时代背景在人类进步的一段长时间范围内，许多工具、机械和方法被提出来；不同的原料用不同的工具来加工。原料及其处理过程已经变成了推动人类进步不可缺的一部份。在当前世界中日益激烈的竞争和人们追求幸福生活的今天，物质的功能已经远远超出了人类现有的并不断增长的知识及想象。例如：神秘原料功能，半导体材料，原料能量有吸力的材料，在航空领域中占有70%份额的强力铝合金45um的薄金属片，用各向异性深冲压金属板在1%以下；电子铝箔与强耐热铝合金已经被应用到航空、宇宙及深海领域中，等等；在原料加工加工领域中不同的时间段里，材料重要发展趋势就这样形成了： （1）在特殊的物

47、理领域里制造原料加工机械，是为了能有特殊的质地结构和辅助性的加工功能。例如：运用热能和机械能能够突破科学技术的极限，将一些不常用的能量，例如：微波、化学能、生物能等等，一个接一个的被引入到材料加工中来，因此一些加工特殊能量原材料的加工设备就被制造出来了。 （2）突破传统的物质限制，将溶化、凝固、造型一体化，然后加热得到具有特殊功能的原料，这样就可以降低加工费用。例如：材料加工整形技术，比如像快速翻滚，喷雾处理、塑胶成型、喷射造型法、高能量射束等等被应用。 （3）原料加工处理正在向高速、重载和高精度在线控制方向上迈进。例如：轧制速度达到130m/s，压力变形已达到300MPa，尺寸精度达到了0.

48、1um，成型精度已达到0.1i；浓度精度已达到0.1MPa。由于这些原因，原料加工机械设备设计理论将科学与技术相关联的领域有机的结合起来设计生产一中新概念材料加工设备是可能的。2对于新概念材料加工设备的期望功能 （1）要有能力生产具有特殊物质的领域；能传送那些对于新概念材料加工在特定的物质环境下是非常必要的特殊能流。例如：在高温环境下能使那些高温波或者脉冲以超过104106K/s的速度冷却下来；将外表面的凝固、变形合成一体，然后在将超强接触面应力重新组合成新的分界面；融化的大金属薄片的湍流；随机的低频率磁场用于金属末加热的微波、用于大量凝固的超声波等等都已经被应用了。 （2）有能力在临界状态下工作，因此高稳定性和理想性能的处理设备是在加强技术条件和室外操作的保证。例如：禁止在润滑状态下边界上的摇晃；在特有的摩擦状态下的抗震能力；有韧性的连接管的合力稳定性和干扰稳定性与轴相比更易驱动系统。 （3）有能力精确的控制原料加工而获得低损耗、高功率、高性能的原料加工。例如：精确的在线监测产品成型；在线监测和在线调整产品品质和器具还有在线控制金属、塑胶成型的程序。产品的精确度指数可以列举如下：宏观上精确度可达到0.1um，微观上的晶状体结构非常