有限元分析系统的发展现状与展望外文翻译演示教学

Finite element analysis system development present situation and forecast

Along with modern science and technology development, the people unceasingly are making the faster transportation vehicle, the large-scale building, the greater span bridge, the high efficiency power set and the preciser mechanical device. All these request engineer to be able precisely to forecast in the design stage the product and the project technical performance, needs to be static, technical parameter and so on dynamic strength to the structure as well as temperature field, flow field, electromagnetic field and transfusion carries on the analysis computation. For example analysis computation high-rise construction and great span bridge when earthquake receives the influence, has a look whether can have the destructive accident; The analysis calculates the nuclear reactor the temperature field, the determination heat transfer and the cooling system are whether reasonable; Analyzes in the new leaf blade the hydrodynamics parameter, enhances its operating efficiency. The sell may sum up as the solution physics question control partial differential equations often is not impossible.

In recent years the finite element analysis which develops in the computer technology and under the numerical analysis method support(FEA, Finite Element Analysis) the side principle for solves these complex project analysis estimation problems to provide the effective way. Our country in " 95 " Plan period vigorously promotes the CAD technology, mechanical profession large and middle scalene terries CAD popular rate from " 85 " End 20% enhances that present 70%.With enterprise application of CAD, engineering and technical personnel has gradually get rid drawing board, and will join the main energy how to optimize the design, engineering and improving the quality of products, computer-aided engineering analysis (CAE. Computer Aided Engineering) method and software will be the key technical elements .

ln engineering practice, finite element analysis software and CAD system integration design standards should be a qualitative leap, mainly in the following aspects :

The increase design function, reduces the design cost;

Reduces design and the analysis cycle period;

Increase product and project reliability;

Uses the optimized design, reduces the material the consumption or the cost;

Discovers the latent question in advance before the product facture or the project construction;

Simulates each kind of experimental plan, reduces the experimental time and the funds;

Carries on the machine accident to analyze, search accident cause factor.

In vigorously promotes the CAD technology today, from the bicycle to the aerospace craft, all designs manufacture all will not be able to leave the finite element analysis computation, FEA obtains the more and more widespread value in the engineering design and the analysis. The next chart is the American San Francisco bay bridge earthquake responds the computation the finite element analysis model. The development direction and on significant progress international early20th century in the end of the 50's, at the beginning of the 60's has the formidable function on the investment massive manpower and the physical resource development the finite element analysis procedure. What is most famous was (NASA) entrusts US by American country Space Agency in 1965 to calculate the NASTRAN finite element analysis system which the scientific company and the Bell aerospace system company developed.

This system development until now had several dozens editions, is in the present world the scale is biggest, the function strongest finite element analysis system. From at that time to the present, the world each place development facility and the university also developed one batch of scales smaller but to use nimble, the price is lower special-purpose or general finite element analysis software, mainly had German ASKA, England's PAFEC, France's company's the and so on SYSTUS, US'S ABQUS, ADINA, ANSYS, BERSAFE, BOSOR, COSMOS, ELAS, MARC and STARDYNE product. Now on the international FEA method and the software development presents below some tendency characteristics:

1.develops from the pure structure mechanics computation to solves many physical

fields question finite element analysis method most early is comes from the structure matrix analysis development, gradually promotes to the board, the shell and the entity and so on the continual body solid mechanics analysis, the practice proved this is one extremely effective numerical analysis method. Moreover the or etically also already proved, so long as uses in to be separated solution object the

unit enough to be small, the obtained solution may enough approach to the precise value.

Therefore the recent years finite element method has developed question the and so on hydromechanics, temperature field, electricity conduction, magnetic field, transfusion and sound field solution computation, recently developed solves several inter disciplinary studies. the questions. For example when the air current flows a very high iron tower to have the distortion, but the tower distortion in turn affects to the air current flows. This needs to use the solid mechanics and the hydrodynamics finite element analysis finally overlapping iteration solves, namely so-called " Flows solid coupling " Question.

2 Progresses from the solution linear project question to the analysis non-linear problem along with the science and technology development, the linear theory already by far could not satisfy the design there quest. For example in construction profession high-rise construction and great span hanging bridge appearance, request consideration geometry non-linear problem and so on structure big displacement and big strain; Astronautics and power engineering high temperature part existence thermal deformation and thermal load, also must consider the material the non-linear problem; Such as the plastic, the rubber and the compound material and so on each kind of new material appearance ,only depends on the question which the linear computation theory is insufficient to solve meets, only has uses the non-linear finite element algorithm to be able to solve. It is well known, the non-linear value computation is very complex, it involves to the very many special mathematics question and the operation skill, thanks the general engineering technical personnel to grasp very much. Has spent massive specialty and so on manpower and investment development such as MARC, ABQUS and ADINA for this recent years overseas some companies to solution non-linear problem finite element analysis software, and widely applies to the project practice. These software common characteristics are have the highly effective non-linear solution as well as rich and the practical non-linear material. Definitely.

3 The enhancement visible pretag e modelling and the post positioned data processing function early time finite element analysis software research key lies in infers new high efficiency solution method and the high accuracy unit. Along with the numerical analysis method gradually consummation, the computer operating speed rapid development, the entire computing system uses in to solve the operation in

particular the time more and more few, but the data preparation and the operation result performance question day by day is actually prominent. On the present project workstation, solves to contain 100,000 equations the finite lement models only to need to use several dozens minutes. But if establishes this model with the manual way, then the rehandling massive computed result must use several week-long time. May not exaggerate said, engineer calculates a project question when the analysis has 80% above the energy all to spend in the data preparation and the result analysis. Therefore the present nearly all shangye finite element software all has the function very strong pretage modeling and the post positioned data processing module. Is emphasizing " Visible " Today ,very many procedures have all established to user extremely friendly GUI (Graphics User Interface), enables the user direct-viewing fast to carry on the grid automatic division by the visible graphic mode, the production finite element analysis needs the data, and the massive computed result will reorganize the distortion chart, the equivalentd is tribution cloud chart according to the request, will be advantageous for the extreme value search and needs the data to tabulate the output.

4 With the CAD software seamless integration now the finite element analysis system another characteristic is and the general CAD software integrated use namely, after uses CAD software to complete the part and the components modeling design, automatically produces the finite element grid and carries on the computation, if analyzes the result does not conform to the design requirement then recarries on the modeling and the computation, until satisfaction, thus enormously raised the design level and the efficiency.

The complex project analysis question today, which engineer may quickly solves in integrated CAD and in the FEA software environment in before is unable to deal with. Therefore now all shangye finite element system business all has developed and famous CAD software (for example Pro/ENGINEER, Unigraphics, SolidEdge, SolidWorks, IDEAS, Bentley and AutoCAD and so on) connection.

5 Basically in Wintel platform development early time finite element analysis software all is in the large and middle scale computers(mainly is Mainframe) on the development and the movement, after wards also developed take the project workstation (EWS, Engineering WorkStation) as the platform, their common characteristic all uses the UNIX operating system.. The PC machine appearance caused the computer the application to have he fundamental change, engineer had

longed for completed the complex project analysis on the desk the dream to become the reality. But early PC machine uses 16 CPU and the DOS operating system, in the memory public block data is restricted, at that time there fore calculated the model the scale not to be able to surpass 10,000 steps equations. Microsoft the Windows operating system and 32 Intel Pentium processor promoting for used in the finite element analysis PC machine to provide essential software and the hardware supports the platform. Therefore on the current international famous finite element procedure research and the development organization all in abundance move theirs software the value to the Wintel platform in. Next cava logged version environment and the SGI workstation simultaneously calculates the solution time with ADINA the V7.3 in PC machine Windows on the NT which 4 projects examples needed. May see the newest upscale PC machine solution ability already and center low-grade EWS is equally matched.

In order to will develop on the large and middle scale computers and EWS the finite element procedure will move the value to PE machine on, frequently will need to use Hummingbird Corporation simulation software Exceed. Does this the result quite is troublesome, moreover cannot fully use the PC machine software and hardware resources. Therefore recently some companies, for example IDEAS, ADINA and R&D starts in the Windows platform to develop the finite element procedure, is called as " Native Windows" The edition, meanwhile has the finite element routine package which in on Linux operating system environment develops in PC machine.

The domestic development situation and the prospect in 1979 US'S SAP5linear structure was static, the mechanical analysis procedure transplants successfully to the domestic introduction, raised the application general finite element procedure to analyze the computation project question the high tide. This high tide continuously continued to 1981 the ADINA non-linear structure analysis procedure introduction, many continuously was unable the project difficult problem which solved all to be easily solved for a while. Everybody also starts to realize indeed is engineer carries on then is computation to the finite element analysis procedure using the computer the important tool。At that time but was restricted in the domestic large and middle scale computers very few, probably only had the Hangzhou steam turbine factory Siemens7738 and the Shenyang air blower factory IBM4310installment has the above procedure, therefore the user mathematics problem was not extremely convenient,

moreover the expense was expensive. The PC machine appearance and its the performance miracle enhancement, for transplanted and develops the PC edition finite element procedure to provide the essential movement platform.

May say domestic FEA software the development continuously revolves the PC platform to make the issue. Compares successful and has (above comparatively multiuser 100) the finite element analysis system in the domestic development to have the Dalian technical Universit beijing mechanics department FIFEX95, Beijing University mechanics and scientific engineering department's SAP84, Chinese farm machine arcade my of science's MAS5.0 and Hangzhou automation technical institute's MFEP4.0 and so on. But just like above-mentioned, the overseas very many famous finite element analysis company already formerly a year not spare a glanced to the PC platform transforms for craves the development, to the domestic FEA procedure development said developed the PC edition no longer to have the superiority, but should perform from following several aspects diligently:

1.Research developments solves the non-solid mechanics and the interdisciplinary

studies. FEA procedure passes through several dozens years research and the development, used in to solve the solid mechanics the finite element method and software already quite is mature, now studies the front question was the hydrodynamics, may compress and the compressible flow body not flow and so on non- solid mechanics and the interdisciplinary studies question. Because domestic not similar function commercialized software, therefore overseas software sells extremely expensively. In order to break this kind of monopoly aspect, we must develop have the independent copy right, use in to analyze the fluid and so on non- solid mechanics and interdisciplinary studies. software.

Because the hydromechanics question far is much more complex than the solid, moreover very little has ready-made software to be allowed to profit from, therefore needs to invest the massive manpower and the funds. This must have the country and the major industry group supports.

2.Developments has the Chinese characteristic the automatic modeling

technology and the GUI development modeling technology and the GUI investment states the topic compared to front to have little many, but actually may greatly enhance FEA software the performance and the user receptivity, thus gets up the twice the result with half the effort effect. The domestic many people did in this aspect have very worked, but because at that time PC machine on graph strut

environment limited, therefore the development effect not really was all ideal. In Windows has provided the OpenGL graph standard, for applied visible graph technology development GUI on PC machine to provide the powerful tool.

OpenGL is the high performance graph and the interactive ground view processing standard which now on international recognizes, applies three dimensional graph software which it develops deeply specialized technical personnel's cherish, at present in the world occupied the dominant position the computer company all to use this standard. Just like front states, in recent years overseas had the FEA procedure has abandoned simulation software, directly developed the finite element procedure in the Windows platform. The Hangzhou automation technical institute 1997-1999 year uses the OpenGL graph standard and corresponding Visual C++ and so on programs the tool, successfully has developed set of visible finite elements routine packages on PC machine. It can direct-viewing pass to " Menu" " Window " " Dialog box " With " Chartsign "

And so on visible graph picture and mark operation, automatically establishes the finite element analysis model, and by interactive side Buddhist ritual procedures realization computed result visible processing, thus may greatly enhance limitedly raises the analysis the efficiency and the accuracy, also is advantageous for the user to study and to grasp.

3.With had the our country independent copyright front the CAD software

integration already to say, now a finite element method important characteristic is and the CAD software seamless in the gration. FEA procedure voluntarily develops which as our country, first must consider and our country independent copyright CAD software integration. Because the finite element analysis mainly uses in the shape quite complex spare part, therefore must with have the three dimensional modeling function and the CAD software integration, causes the design and analysis in close integration with, merges in tone organic whole.

In this paper, the static stress of the coupling is analyzed by the finite-element software ANSYS8.0.Through computing and analyzing the stress and the displacement are got and it gives the base theory to improve the force condition and the structure of the coupling. What is more the paper illustrates the method of apply finite-element analysis to the calculation of internal force in design.

Has to the center tenon shaft coupling, depends in a half shaft coupling the raised shoulder to coordinate with another half shaft coupling on scoop channel but to the