機(jī)械外文翻譯--材料制備機(jī)械設(shè)計(jì)理論中的新趨勢(shì)和新問題-文庫吧
2025-05-14 18:11 本頁面
【正文】 h 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 ,precision 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 ing to m , microstructure uniformity to crystal lattice ,strength error to 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. 4 3 Science Problems and Study Contents of Metal Material Processing Machine Under the Circumstance of Extraordinary Physical Field In 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 Field A brand new microstructure can be obtained through continuously large deformation and fast solidifying 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 conversion ,and to establish mathematical model . 3. 2 Friction Constraint Mechanism of Plastic Flow Interface of Material Processing Machine The coupling between operation mechanism and workpiece is very plicated because plastic flow is present in processing interface. The interface state , determined 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 these 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 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 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 Field To build the super strength pressure field on large area is one of basic function of material processing machine , and it is also necessary to 5 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 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 super 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 Sliding Pair With Structure Bias Load With regard to statically indeterminate structure ,load distribution of constraint point is determined by deformation patibility condition. However ,concerning some plane large size statically indeterminate structure with sliding degree of freedom in third dimension ,load distribution can not be determined by deformation patibility 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 patibility condition ,etc) . 3. 5 Coupling Mechanism and Stability of Multi Physical Fields in Material Processing Systems In the wake of system function being more and more diversified , conventional technology limits in material processing machine is being broke through unceasingly ,system structure also bees increasingly plicated ,and system performance bees increasingly multi causal . For example ,any instantaneous state of roller in fast rolling mills is affected by elastic d
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