- Email: [email protected]
Superconductor applications in the automotive industry
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14. Integrated Information Support System
Conference Reports
Support System, Common Data Model subsystem".
Common Data Model Subsystem A lso presented in this session: Jerry Althoff and Joe Shumski (Control Data Corp., OH, U.S.A.) provided an overview of the common data model subsystem of the integrated information support system. They stressed the benefits it provides to developers of integrated applications and managers of the corporate data resource. Also described in their lecture was the three phases of usage of the common data model subsystem. The major benefits are application program data independence, definition and cont r o l of the enterprise data resource. The three phases are: (1) the definition phase in which the data resource is described, (2) the precompile phase for integrated applications development, and (3) the execution phase in which integrated data results are obtained. Althoff and Shumski's presentation was entitled "Integrated Information
"IISS Project Orientation" and "lISS Technical Overview,' by Lestra K. Wagner (Boeing Military Airplane Company, Wichita, Ks, USA) "IISS Network Transaction Management and Communications" by Sandy Mustard (Boeing Computer Services) "User Interface/Virtual Terminal Interface'! by S.L. Barker, R.S. Morenc, C.J. Morenc and E.M. Butterworth (Structural Dynamics Research Corp.) The AUTOFACT'86 Conference: Proceedings are available for US $75.00 ($70.00 for SME Members) from SME Publication Sales, One SME Drive, P.O. Box 930, Dearborn, Michigan 48121, U.S.A. Outside the U.SIA. and Canada, the Proceedings are available from North-Holland. 1987, 770 pages.
Superconductor Applications in the Automotive Industry Zurich, Switzerland 7-9 October 1986
General Applications Keynote Lecture
The conference provided a unique account of current computational techniques in the automobile industry. Twenty four papers by international experts included crash simulation, analysis in manufacturing, automobile aerodynamics, engine combustion modelling, optimization and the use of expert systems. The conference has particular relevance to the automotive industry and research organisations because of the rapid advance in automotive engineering, the increasing: complexity of automotive design and the equally rapid developments in supercomputer technology. These advances have greatly improved our ability to optimise solutions of increasingly complex problems in a competitive industry. We present below a report on the lectures delivered at this conference.
D. Radaj (Daimler-Benz AG, Stuttgart, F.R.G.) explained that from the very beginning the development of automobiles has been based on calculations for dimensioning. Numerical simulation was seriously hampered until efficient computers became available. Then this field was extended to include finite element as well as flow simulation. The importance of numerical analysis in today's automobile development was shown with reference to the current development requirements. Prerequisites for successful numerical analysis in the automotive industry besides manpower and computer power are qualified modelling and integrated analysis. The use of supercomputers is deemed to be indispensable. Radaj's lecture was entitled "History, Status and Trends of Automotive Numerical Analysis".
Conference Reports
Structural Analysis Keynote Lecture
Computers in Industry
345
ment in the automotive industry. These developments largely centre upon their explicit finite element code PAM-CRASHand the use of supercomputers. They presented examples which demonstrated the diversity of problems that may be tackled with the explicit PAM-CRASHcode and, in each case, the severity of impact that may be achieved.
The development of mass produced automobiles is a continuously growing and changing process temporarily determined by: increasing customer demands; technological progress in various fields (electronics, control techniques, etc.); sociological changes (traffic policy, environment), and the increasing automation of manufacturing. In addition the marketplace demands a continuing product improvement and development, and a proliferation of car model lines - tasks which can only be coped with by judicious applications of computers. Concluding their presentation "Introduction and Use of a Supercomputer at OPEL A.G., for Crash Simulation" K. Hieronimus and E. Nalepa (Adam Opel g6, Technical Development Centre, Russelsheim, F.R.G.) stated that computers will not replace the creativity of engineers. They will, they said, however, support a systematic and extensive integration of up-to-date knowledge into a vehicle layout.
The availability of extremely versatile general purpose finite element programs on the new generation of supercomputers has made it possible for both large and small companies to perform structural analysis to solve some of the largest complex problems on supercomputers. K.S. Kothawala (Engineering Mechanics Research Corporation, Troy, U.S.A.) described NISA II, a finite element analysis program which has taken advantage of the availability of vectorization and/or parallel processing. The vector processing capabilities of the CRAY system has been used to speed up equation solving and eigenvalue extraction algorithms.
Supercomputers
ABAQU.S
In "Supercomputers: A Milestone for Non-Linear Finite Element Applications" E. Sehelke (PORSCHE Research and Development Centre, Weissach, F.R.6.) explained that finite element (FE) programs are the standard tools of calculation in the automotive industry. The universal applicability of this method has led to its increasing usage. He went on to describe how in recent years interest in non-linear FE calculations has markedly increased with regard to automotive design. Such non-linear FE calculations are therefore performed best with supercomputers with essentially higher computation capacities, which therefore, without exaggeration, can be considered milestones in the application of non-linear FE methods.
E.P. Sorensen (Hibbitt, Karlson and Sorensen, Inc., Providence, RI, U.S.A.) described the ABAQUS finite element program and its application to the analysis of automotive components. ABAQUS is designed for general use in nonlinear as well as linear structural and heat transfer problems. A brief overview of the program was provided together with a discussion of the particular element formulations, constitutive models and integration algorithms which make ABAQUSan effective analysis tool. A few general application areas were described to illustrate the code's application to automotive structures.
Numerical Techniques
A new innovative numerical technique, the discrete element method, for the solution of two and three dimensional discontinuum solid mechanics problems was presented by G. Hocking (Intera Technologies Inc., Denver, co, U.S.A). The basic equations for solution in the discrete element method were described. Illustrations of the applicability of the method were highlighted for two
In their contribution J.F Chedmail, P. Du Bois and A.K Pickett (ESl GmbH, Eschborn, F.R.G), E. Haug, B. Dagba and G. Winkelmfiller (ESl S.A., Rungis, France) outlined the most recent developments and experiences gained at Engineering System International (ESI) for crashworthiness assess-
NISA II
Crash Simulation
346
Computersin Industry
impact collision problems, one involving brittle fracture much like a windscreen impact, the other the ductile plastic flow of a thin wall box section component being restrained by contact with another member. In both of these problems, complex contact detection, large displacement nonlinear behavior and discrete fracture phenomena are required to accurately simulate the crash phenomena.
Conference Reports
puters are of particular interest due to their improved cost efficiency. He discussed the finite element software system PERMAS in some detail. The hypermatrix scheme of PERMAS provides a general data structure for sparcely populated matrices of very large dimensions that is particularly well-suited for vectorization. Schrem coneluded by stating that in the near future it will be possible to run even quite large finite element applications during an online session.
Boundary Element Program Computational Aspects Since its first release onto the market in 1981. the BEASY analysis package has become firmly established as the leading boundary element analysis system available. Because of its capability to simplify the modelling of problems in heat transfer, stress and thermal stress, BEASY has become increasingly popular with automotive companies worldwide. J. Trevelyan (Computational Mechanics BEASY Ltd, Southampton, U.K.) presented the latest developments in the BEASY package and described the use of the optimised supercomputer versions in varying automotive engineering applications. The presentation was called "New Developments in the BEASYBoundary Element Program for Thermal and Stress Analysis".
Crash Experiences In their presentation "FEM - CRASH Experiences at Volkswagen Research" T. Scharnhorst and R-W. Schettler-KiJhler (Volkswagen AG. Wolfsburg, F.R.G.) explained how linear finite element calculations are sufficiently accurate to predict the stiffness of a car body subjected to torsional and bending stresses as soon as the early stages of the pre-development phase, even if no prototype is available. The acceleration of the calculation process by supercomputers from many days to a few hours is an important and. as regards capital costs, decisive step.
Implementation and Application E. Schrem (INTES Ingenieurgesellschaft fiir technische Software mbH, Stuttgart, F.R.G) exp l a i n e d in "Experience with Implementation and Application of Finite Element Software on CRAY Supercomputers" that apart from their unquestionable high processing speed, modem supercom-
Particular attention was paid by N. Rebelo, S. Nakazawa, T.B. Wertheimer and J.C. Nagtegaal (MARC Analysis Research Corporation. Palo Alto. CA. U.S.A.) to the application of the finite element method to metal forming problems. In "Computational Aspects of Finite Element Analysis in Manufacturing" they discussed finite deformation metal forming analysis. A comparative study of several algorithms emphasizing computational efficiency was made. A typical metal forming problem was chosen as a model problem, and run under conditions as similar as possible except for the algorithms used to achieve a solution. A comparison of execution times on the same computer, using the general purpose finite element program MARC was reported. A meaningful example was presented to demonstrate the many factors associated with metal forming analysis.
Three-Dimenswnal Re-Zoning Metal-forming processes invariably impose very large deformations on the material being worked and thus pose special problems for any numerical technique which attempts to simulate such processes. Typically any initial mesh configuration quickly becomes so distorted by the imposed boundary conditions that it is not possible to continue further computations. Thus it becomes essential to re-zone the distorted mesh at intervals in order to continue the numerical simulations to a satisfactory conclusion. Further, the large amount of plastic deformation acts as a heat source and for realistic simulations a coupled thermomechanical numerical solution scheme is necessary. G.S. Kalsi (Principia Mechanica Ltd. London, U.K.) described a numerical procedure which embodies an automatic three-dimensional
Conference Reports
re-zoning facility and which can perform coupled thermo-mechanical analysis. Results were presented showing comparisons between experimental measurements and numerical predictions.
Aerodynamics and Combustion Keynote Lecture Over the past decade computer simulation of internal and external flows in the automotive industry has gained increasing popularity. W. Brandstiitter and R.J.R. Johns (AVL Prof. List GmbH, Graz, Austria) reviewed some of the areas in which such calculations are making an impact. It was demonstrated that numerical solutions of the 2- and 3-dimensional, time dependent Navier-Stokes equations, including the important effects of turbulence, can be obtained using today's superminicomputers. However, the need for faster turnaround, especially for 3-dimensional car aerodynamics modelling, requires the use of supercomputers together with software optimisation. Methods of achieving this were indicated and future research trends for the modelling of 3dimensional internal and external flows in the automotive environment were discussed.
Keynote Lecture For industry computational fluid dynamics (CFD) has to be integrated as a computer aided engineering (CAE) application. The main task is to generate a more or less complex input, process a flow solver, and produce an easy to understand output in engineering form. The task can only be fullfilled efficiently if soft- and hardware for preand postprocessing, mesh generation software and numerical algorithms are of high standards along with fast number crunching computer hardware. The weakest point in this loop is limiting the capabilities. Faster computers and algorithms automatically lead to an imbalance if the manpower cost and time of numerical simulations is not reduced consequently by using expert systems. W. Schmidt and B. Wagner (Dornier Gmbn, Friedrichshafen, F.R.G.) discussed some of the design principles they are following to establish large scale numerical simulation in aerodynamics.
Computers in Industry
347
Keynote Lecture In "Engine Combustion Modeling: Prospects and Challenges" K. Meintjes (General Motors Research Laboratories, Warren, MI, U.S.A.) started with a general discussion of recent developments. He went on to describe the supercomputer's needs, preparation - grid generation, interpretation understanding the results, and multidimensional combustion models. In conclusion Meintjes mentioned two major challenges: to resolve the imbalance of effort required when using the models and the urgent need for a predictive model for turbulent combustion.
Turbulent Combustion The interaction between turbulence and combustion, called "turbulent combustion" is a crucial phenomenon to be included within an appropriate model in a general code for combustion in the engine. Two models were considered by B. Arg,ueyrolles, P. Souhaite, S. Gauffie and R. Borg,hi (R.N.U. Renault-Peugot S.A., C.N.R.S., France): the first was especially chosen to make evident the crucial features that a turbulence model must have in order to be used for turbulent combustion; it assumes that the mean reaction rate is fully controlled by turbulence, and a second one, of which a greater validity is expected, assumes that the combustion can be represented by a single reaction but with finite rate, and the influence of fluctuations is taken into account through a "presumed p.d.f, model". They described the principles and basic formulae of the two models and then discussed these models with respect to their particular use for a reciprocating engine and finally presented the results of numerical computations with respect to observations in real engines.
Automobile Aerodynamics The prediction of the drag and lift characteristics for a wide class of bluff bodies of complex geometries, such as road vehicles, where extensive separations generating large pressure drag occur, remains an unanswered challenge. J.M. Summa and F.A. Dvorak (Analytical Methods Inc., Redmond, WA, U.S.A.) discussed an iterative potential/viscous flow calculation method, program VSAERO (Vortex Separation AEROdynamics),
348
Computersin Industry
along with its application to some automobile shapes. Since this program utilizes integral methods for both the potential and viscous flows. calculations are relatively fast compared with differential equation methods.
Fluid Flow Problems In "Automotive Fluid Flow Problems and Their Solution Using Computational Methods" N. Rhodes (Concentration Heat and Momentum Ltd, Wimbtedon, U.K.) discussed Computational Fluid Dynamics (CED). He stated that the use of CFD methods is becoming more widely used in automotive design and that although mathematical models may not give the answer to the last decimal place, they do give the designer freedom to innovate without the restrictions imposed by hardware development.
Simulation Software In the last few years there has been significant progress in the development of software for automobile aerodynamic simulation. K.P. Misegades (Cray Research Inc., Mendota Heights, M'N, U.S.A.) presented an overview of twelve computer programs that are capable of such simulations, and are available to users of CRAV supercomputers: VSA~RO, 3DFLOW, DORNIER (panel method and Euler equation solver), ~UFLEXPHOENICS, FLUENT. VAST, AVL. FIDAP, INS3D.
Computer-AidedEngineering Keynote Lecture G.N. Vanderplaats (University of California, Santa Barbara, CA, U.S.A.) briefly reviewed the history and technology of design optimization and demonstrated that this technology has matured to the point that it can be considered a practical design tool. He briefly outlined the basic concepts of design optimization and discussed some applications in aerodynamic and structural optimization to demonstrate the present state of the art. Finally he discussed expected advancements in the near future and identified the importance of increased computational power.
Con[erenceReports
Adams ADAMS(Automatic Dynamic Analysis of Mechanical Systems) is an easy to use program for the kinematic, static and dynamic analysis of threedimensional mechanical systems. The automotive industry is a major user of this program with a large number of applications which range from the analysis of simple mechanisms such as door locks. windscreen wipers and gearshift linkages to suspension kinematics and ultimately full vehicle ride and handling simulation. M. Bartels (TEDASGmbIa. Marburg, F.R.G.) and M. Stanton (Technological Research, Ford Motor Company Ltd, U.K.) provided an introduction to ADAMS. They also presented one of the most recent full vehicle simulation projects by Ford Technological Research, u.K. The model is for use in the study of both ride and handling and incorporates complex non-linear suspension characteristics. Also included in the model is the ability to simulate advanced adaptive suspension systems.
MSC/NASTRAN M. Chargin and H. Miura (NASA Ames Research Center, Moffett Field, CA, U.S.A.) and G. Clifford (Cray Research Inc., Mendota Heights. MN, U.S.A.) described an automated design technique for modifying structural models. The technique provides design engineers with a method of designing or modifying a structure to achieve given objectives. Specifically, modifications of a structure excited by harmonic loads of constant frequency, are considered with the intent of reducing steady state vibration amplitudes. Two example problems were solved to demonstrate the capability of the techniques. Engineermg Decision-Making S. C-Y. Lu (University of Illinois at UrbanaChampaign, Urbana, IL. U.S.A.) suggested a complete decision-making framework that utilizes both the At/knowledge-based expert systems approach and supercomputing technology to improve the decision-making productivity of engineers. Dilemmas in current computer-aided engineering activities were summarized. The impact of knowledgebased expert systems and supercomputers on these activities was discussed. The proposed framework
Conference Reports
defines supercomputers as "information engines" and expert systems as "reasoning engines", and suggests a way for them to cooperatively contribute their distinctive strengths to the decision-making process of engineers. He indicated that these two important techniques are in fact mutually complementary and that many development and research interactions are needed in the future. The Proceedings of the conference, entitled Super-
computer Applications in Automotive Research and Engineering Development, edited by C. Marino
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(Cray Research, Inc., Mendota Heights, MN 55120, U.S.A.), were published by Computational Mechanics P u b l i c a t i o n s , Southampton, ISBN 0-905451-54-6; Boston, Los Angeles, ISBN 0-931215-29-3. Price: US $105, 452 pages, case bound. Available from Computational Mechanics Publications, Ashurst Lodge, Ashurst, Southampton, SO4 2AA, U.K.. For U.S.A., Canada and Mexico: Computational Mechanics Inc., 25 Bridge Street, Billerica, MA 01821, U.S.A. and Computational Mechanics Inc., Suite 265, 17744 Skypark Circle, Irvine, CA 92714, U.S.A..
AV¢86" Alvey Computer Vision and Image Interpretation Meeting The conference, AVC86: Alvey Computer Vision and Image Interpretation Meeting, was held at the University of Bristol, U.K.. on September 22-25, 1986, and was organised by the Alvey Vision Club. The secretary of the club is K.M. Crenell (Rutherford Appleton Laboratory, Oxford, U.K.). Attendees represented academic institutions and industry. The conference programme consisted of 8 sessions followed by discussions, two invited papers and an after dinner presentation on the first full day of the conference entitled "The Future". The major session topics were: - 2½D Sketch Object Models, Matching and Geometry I Object Models, Matching and Geometry II Image Descriptions and Segmentation Applications - Hardware - Motion Associative Networks We present below a report on the lectures given at the conference.
bined together for specific tasks at a slower, higher level. Human "low-level" operations can extract edges, and recognise objects but they also use context, e.g. face recognition is very fast. Ullman went on to say that we can understand the character string "Ideal" as the word "ideal", where the first and last letters look the same but have different meanings. There seem to be fast ways of recognising shapes which are roughly ellipsoidal. He concluded by stating that this problem has applications to the fast detection of defects in printed circuit boards.
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-
2½D Sketch
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-
-
Opening Session Visual Routines S. Ullman (Weizman Institute of Science, Israel) said that computer vision might profitably copy the human vision system, which appeared to use "low-level" fast operations which could be com-
A lvey 2.5D Sketch Project In this presentation the current structure of an experimental, integrated 2.5D sketch system was outlined. A. Blake (University of Edinburgh, Scotland, U.K.) and J. Mayhew (University of Sheffield, Sheffield, U.K.) stated that its purpose was to facilitate experimentation in integration of low-level visual competences. They described the three main components: a set of base representations, a set of knowledge sources, and the regionedge-vertex (REV) graph. In conclusion they reported that currently most of the base representations are implemented; access functions for the REV graph are in place, together with trace facilities and an experimental "consistency mainte-
Computersin Industry
14. Integrated Information Support System
Conference Reports
Support System, Common Data Model subsystem".
Common Data Model Subsystem A lso presented in this session: Jerry Althoff and Joe Shumski (Control Data Corp., OH, U.S.A.) provided an overview of the common data model subsystem of the integrated information support system. They stressed the benefits it provides to developers of integrated applications and managers of the corporate data resource. Also described in their lecture was the three phases of usage of the common data model subsystem. The major benefits are application program data independence, definition and cont r o l of the enterprise data resource. The three phases are: (1) the definition phase in which the data resource is described, (2) the precompile phase for integrated applications development, and (3) the execution phase in which integrated data results are obtained. Althoff and Shumski's presentation was entitled "Integrated Information
"IISS Project Orientation" and "lISS Technical Overview,' by Lestra K. Wagner (Boeing Military Airplane Company, Wichita, Ks, USA) "IISS Network Transaction Management and Communications" by Sandy Mustard (Boeing Computer Services) "User Interface/Virtual Terminal Interface'! by S.L. Barker, R.S. Morenc, C.J. Morenc and E.M. Butterworth (Structural Dynamics Research Corp.) The AUTOFACT'86 Conference: Proceedings are available for US $75.00 ($70.00 for SME Members) from SME Publication Sales, One SME Drive, P.O. Box 930, Dearborn, Michigan 48121, U.S.A. Outside the U.SIA. and Canada, the Proceedings are available from North-Holland. 1987, 770 pages.
Superconductor Applications in the Automotive Industry Zurich, Switzerland 7-9 October 1986
General Applications Keynote Lecture
The conference provided a unique account of current computational techniques in the automobile industry. Twenty four papers by international experts included crash simulation, analysis in manufacturing, automobile aerodynamics, engine combustion modelling, optimization and the use of expert systems. The conference has particular relevance to the automotive industry and research organisations because of the rapid advance in automotive engineering, the increasing: complexity of automotive design and the equally rapid developments in supercomputer technology. These advances have greatly improved our ability to optimise solutions of increasingly complex problems in a competitive industry. We present below a report on the lectures delivered at this conference.
D. Radaj (Daimler-Benz AG, Stuttgart, F.R.G.) explained that from the very beginning the development of automobiles has been based on calculations for dimensioning. Numerical simulation was seriously hampered until efficient computers became available. Then this field was extended to include finite element as well as flow simulation. The importance of numerical analysis in today's automobile development was shown with reference to the current development requirements. Prerequisites for successful numerical analysis in the automotive industry besides manpower and computer power are qualified modelling and integrated analysis. The use of supercomputers is deemed to be indispensable. Radaj's lecture was entitled "History, Status and Trends of Automotive Numerical Analysis".
Conference Reports
Structural Analysis Keynote Lecture
Computers in Industry
345
ment in the automotive industry. These developments largely centre upon their explicit finite element code PAM-CRASHand the use of supercomputers. They presented examples which demonstrated the diversity of problems that may be tackled with the explicit PAM-CRASHcode and, in each case, the severity of impact that may be achieved.
The development of mass produced automobiles is a continuously growing and changing process temporarily determined by: increasing customer demands; technological progress in various fields (electronics, control techniques, etc.); sociological changes (traffic policy, environment), and the increasing automation of manufacturing. In addition the marketplace demands a continuing product improvement and development, and a proliferation of car model lines - tasks which can only be coped with by judicious applications of computers. Concluding their presentation "Introduction and Use of a Supercomputer at OPEL A.G., for Crash Simulation" K. Hieronimus and E. Nalepa (Adam Opel g6, Technical Development Centre, Russelsheim, F.R.G.) stated that computers will not replace the creativity of engineers. They will, they said, however, support a systematic and extensive integration of up-to-date knowledge into a vehicle layout.
The availability of extremely versatile general purpose finite element programs on the new generation of supercomputers has made it possible for both large and small companies to perform structural analysis to solve some of the largest complex problems on supercomputers. K.S. Kothawala (Engineering Mechanics Research Corporation, Troy, U.S.A.) described NISA II, a finite element analysis program which has taken advantage of the availability of vectorization and/or parallel processing. The vector processing capabilities of the CRAY system has been used to speed up equation solving and eigenvalue extraction algorithms.
Supercomputers
ABAQU.S
In "Supercomputers: A Milestone for Non-Linear Finite Element Applications" E. Sehelke (PORSCHE Research and Development Centre, Weissach, F.R.6.) explained that finite element (FE) programs are the standard tools of calculation in the automotive industry. The universal applicability of this method has led to its increasing usage. He went on to describe how in recent years interest in non-linear FE calculations has markedly increased with regard to automotive design. Such non-linear FE calculations are therefore performed best with supercomputers with essentially higher computation capacities, which therefore, without exaggeration, can be considered milestones in the application of non-linear FE methods.
E.P. Sorensen (Hibbitt, Karlson and Sorensen, Inc., Providence, RI, U.S.A.) described the ABAQUS finite element program and its application to the analysis of automotive components. ABAQUS is designed for general use in nonlinear as well as linear structural and heat transfer problems. A brief overview of the program was provided together with a discussion of the particular element formulations, constitutive models and integration algorithms which make ABAQUSan effective analysis tool. A few general application areas were described to illustrate the code's application to automotive structures.
Numerical Techniques
A new innovative numerical technique, the discrete element method, for the solution of two and three dimensional discontinuum solid mechanics problems was presented by G. Hocking (Intera Technologies Inc., Denver, co, U.S.A). The basic equations for solution in the discrete element method were described. Illustrations of the applicability of the method were highlighted for two
In their contribution J.F Chedmail, P. Du Bois and A.K Pickett (ESl GmbH, Eschborn, F.R.G), E. Haug, B. Dagba and G. Winkelmfiller (ESl S.A., Rungis, France) outlined the most recent developments and experiences gained at Engineering System International (ESI) for crashworthiness assess-
NISA II
Crash Simulation
346
Computersin Industry
impact collision problems, one involving brittle fracture much like a windscreen impact, the other the ductile plastic flow of a thin wall box section component being restrained by contact with another member. In both of these problems, complex contact detection, large displacement nonlinear behavior and discrete fracture phenomena are required to accurately simulate the crash phenomena.
Conference Reports
puters are of particular interest due to their improved cost efficiency. He discussed the finite element software system PERMAS in some detail. The hypermatrix scheme of PERMAS provides a general data structure for sparcely populated matrices of very large dimensions that is particularly well-suited for vectorization. Schrem coneluded by stating that in the near future it will be possible to run even quite large finite element applications during an online session.
Boundary Element Program Computational Aspects Since its first release onto the market in 1981. the BEASY analysis package has become firmly established as the leading boundary element analysis system available. Because of its capability to simplify the modelling of problems in heat transfer, stress and thermal stress, BEASY has become increasingly popular with automotive companies worldwide. J. Trevelyan (Computational Mechanics BEASY Ltd, Southampton, U.K.) presented the latest developments in the BEASY package and described the use of the optimised supercomputer versions in varying automotive engineering applications. The presentation was called "New Developments in the BEASYBoundary Element Program for Thermal and Stress Analysis".
Crash Experiences In their presentation "FEM - CRASH Experiences at Volkswagen Research" T. Scharnhorst and R-W. Schettler-KiJhler (Volkswagen AG. Wolfsburg, F.R.G.) explained how linear finite element calculations are sufficiently accurate to predict the stiffness of a car body subjected to torsional and bending stresses as soon as the early stages of the pre-development phase, even if no prototype is available. The acceleration of the calculation process by supercomputers from many days to a few hours is an important and. as regards capital costs, decisive step.
Implementation and Application E. Schrem (INTES Ingenieurgesellschaft fiir technische Software mbH, Stuttgart, F.R.G) exp l a i n e d in "Experience with Implementation and Application of Finite Element Software on CRAY Supercomputers" that apart from their unquestionable high processing speed, modem supercom-
Particular attention was paid by N. Rebelo, S. Nakazawa, T.B. Wertheimer and J.C. Nagtegaal (MARC Analysis Research Corporation. Palo Alto. CA. U.S.A.) to the application of the finite element method to metal forming problems. In "Computational Aspects of Finite Element Analysis in Manufacturing" they discussed finite deformation metal forming analysis. A comparative study of several algorithms emphasizing computational efficiency was made. A typical metal forming problem was chosen as a model problem, and run under conditions as similar as possible except for the algorithms used to achieve a solution. A comparison of execution times on the same computer, using the general purpose finite element program MARC was reported. A meaningful example was presented to demonstrate the many factors associated with metal forming analysis.
Three-Dimenswnal Re-Zoning Metal-forming processes invariably impose very large deformations on the material being worked and thus pose special problems for any numerical technique which attempts to simulate such processes. Typically any initial mesh configuration quickly becomes so distorted by the imposed boundary conditions that it is not possible to continue further computations. Thus it becomes essential to re-zone the distorted mesh at intervals in order to continue the numerical simulations to a satisfactory conclusion. Further, the large amount of plastic deformation acts as a heat source and for realistic simulations a coupled thermomechanical numerical solution scheme is necessary. G.S. Kalsi (Principia Mechanica Ltd. London, U.K.) described a numerical procedure which embodies an automatic three-dimensional
Conference Reports
re-zoning facility and which can perform coupled thermo-mechanical analysis. Results were presented showing comparisons between experimental measurements and numerical predictions.
Aerodynamics and Combustion Keynote Lecture Over the past decade computer simulation of internal and external flows in the automotive industry has gained increasing popularity. W. Brandstiitter and R.J.R. Johns (AVL Prof. List GmbH, Graz, Austria) reviewed some of the areas in which such calculations are making an impact. It was demonstrated that numerical solutions of the 2- and 3-dimensional, time dependent Navier-Stokes equations, including the important effects of turbulence, can be obtained using today's superminicomputers. However, the need for faster turnaround, especially for 3-dimensional car aerodynamics modelling, requires the use of supercomputers together with software optimisation. Methods of achieving this were indicated and future research trends for the modelling of 3dimensional internal and external flows in the automotive environment were discussed.
Keynote Lecture For industry computational fluid dynamics (CFD) has to be integrated as a computer aided engineering (CAE) application. The main task is to generate a more or less complex input, process a flow solver, and produce an easy to understand output in engineering form. The task can only be fullfilled efficiently if soft- and hardware for preand postprocessing, mesh generation software and numerical algorithms are of high standards along with fast number crunching computer hardware. The weakest point in this loop is limiting the capabilities. Faster computers and algorithms automatically lead to an imbalance if the manpower cost and time of numerical simulations is not reduced consequently by using expert systems. W. Schmidt and B. Wagner (Dornier Gmbn, Friedrichshafen, F.R.G.) discussed some of the design principles they are following to establish large scale numerical simulation in aerodynamics.
Computers in Industry
347
Keynote Lecture In "Engine Combustion Modeling: Prospects and Challenges" K. Meintjes (General Motors Research Laboratories, Warren, MI, U.S.A.) started with a general discussion of recent developments. He went on to describe the supercomputer's needs, preparation - grid generation, interpretation understanding the results, and multidimensional combustion models. In conclusion Meintjes mentioned two major challenges: to resolve the imbalance of effort required when using the models and the urgent need for a predictive model for turbulent combustion.
Turbulent Combustion The interaction between turbulence and combustion, called "turbulent combustion" is a crucial phenomenon to be included within an appropriate model in a general code for combustion in the engine. Two models were considered by B. Arg,ueyrolles, P. Souhaite, S. Gauffie and R. Borg,hi (R.N.U. Renault-Peugot S.A., C.N.R.S., France): the first was especially chosen to make evident the crucial features that a turbulence model must have in order to be used for turbulent combustion; it assumes that the mean reaction rate is fully controlled by turbulence, and a second one, of which a greater validity is expected, assumes that the combustion can be represented by a single reaction but with finite rate, and the influence of fluctuations is taken into account through a "presumed p.d.f, model". They described the principles and basic formulae of the two models and then discussed these models with respect to their particular use for a reciprocating engine and finally presented the results of numerical computations with respect to observations in real engines.
Automobile Aerodynamics The prediction of the drag and lift characteristics for a wide class of bluff bodies of complex geometries, such as road vehicles, where extensive separations generating large pressure drag occur, remains an unanswered challenge. J.M. Summa and F.A. Dvorak (Analytical Methods Inc., Redmond, WA, U.S.A.) discussed an iterative potential/viscous flow calculation method, program VSAERO (Vortex Separation AEROdynamics),
348
Computersin Industry
along with its application to some automobile shapes. Since this program utilizes integral methods for both the potential and viscous flows. calculations are relatively fast compared with differential equation methods.
Fluid Flow Problems In "Automotive Fluid Flow Problems and Their Solution Using Computational Methods" N. Rhodes (Concentration Heat and Momentum Ltd, Wimbtedon, U.K.) discussed Computational Fluid Dynamics (CED). He stated that the use of CFD methods is becoming more widely used in automotive design and that although mathematical models may not give the answer to the last decimal place, they do give the designer freedom to innovate without the restrictions imposed by hardware development.
Simulation Software In the last few years there has been significant progress in the development of software for automobile aerodynamic simulation. K.P. Misegades (Cray Research Inc., Mendota Heights, M'N, U.S.A.) presented an overview of twelve computer programs that are capable of such simulations, and are available to users of CRAV supercomputers: VSA~RO, 3DFLOW, DORNIER (panel method and Euler equation solver), ~UFLEXPHOENICS, FLUENT. VAST, AVL. FIDAP, INS3D.
Computer-AidedEngineering Keynote Lecture G.N. Vanderplaats (University of California, Santa Barbara, CA, U.S.A.) briefly reviewed the history and technology of design optimization and demonstrated that this technology has matured to the point that it can be considered a practical design tool. He briefly outlined the basic concepts of design optimization and discussed some applications in aerodynamic and structural optimization to demonstrate the present state of the art. Finally he discussed expected advancements in the near future and identified the importance of increased computational power.
Con[erenceReports
Adams ADAMS(Automatic Dynamic Analysis of Mechanical Systems) is an easy to use program for the kinematic, static and dynamic analysis of threedimensional mechanical systems. The automotive industry is a major user of this program with a large number of applications which range from the analysis of simple mechanisms such as door locks. windscreen wipers and gearshift linkages to suspension kinematics and ultimately full vehicle ride and handling simulation. M. Bartels (TEDASGmbIa. Marburg, F.R.G.) and M. Stanton (Technological Research, Ford Motor Company Ltd, U.K.) provided an introduction to ADAMS. They also presented one of the most recent full vehicle simulation projects by Ford Technological Research, u.K. The model is for use in the study of both ride and handling and incorporates complex non-linear suspension characteristics. Also included in the model is the ability to simulate advanced adaptive suspension systems.
MSC/NASTRAN M. Chargin and H. Miura (NASA Ames Research Center, Moffett Field, CA, U.S.A.) and G. Clifford (Cray Research Inc., Mendota Heights. MN, U.S.A.) described an automated design technique for modifying structural models. The technique provides design engineers with a method of designing or modifying a structure to achieve given objectives. Specifically, modifications of a structure excited by harmonic loads of constant frequency, are considered with the intent of reducing steady state vibration amplitudes. Two example problems were solved to demonstrate the capability of the techniques. Engineermg Decision-Making S. C-Y. Lu (University of Illinois at UrbanaChampaign, Urbana, IL. U.S.A.) suggested a complete decision-making framework that utilizes both the At/knowledge-based expert systems approach and supercomputing technology to improve the decision-making productivity of engineers. Dilemmas in current computer-aided engineering activities were summarized. The impact of knowledgebased expert systems and supercomputers on these activities was discussed. The proposed framework
Conference Reports
defines supercomputers as "information engines" and expert systems as "reasoning engines", and suggests a way for them to cooperatively contribute their distinctive strengths to the decision-making process of engineers. He indicated that these two important techniques are in fact mutually complementary and that many development and research interactions are needed in the future. The Proceedings of the conference, entitled Super-
computer Applications in Automotive Research and Engineering Development, edited by C. Marino
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(Cray Research, Inc., Mendota Heights, MN 55120, U.S.A.), were published by Computational Mechanics P u b l i c a t i o n s , Southampton, ISBN 0-905451-54-6; Boston, Los Angeles, ISBN 0-931215-29-3. Price: US $105, 452 pages, case bound. Available from Computational Mechanics Publications, Ashurst Lodge, Ashurst, Southampton, SO4 2AA, U.K.. For U.S.A., Canada and Mexico: Computational Mechanics Inc., 25 Bridge Street, Billerica, MA 01821, U.S.A. and Computational Mechanics Inc., Suite 265, 17744 Skypark Circle, Irvine, CA 92714, U.S.A..
AV¢86" Alvey Computer Vision and Image Interpretation Meeting The conference, AVC86: Alvey Computer Vision and Image Interpretation Meeting, was held at the University of Bristol, U.K.. on September 22-25, 1986, and was organised by the Alvey Vision Club. The secretary of the club is K.M. Crenell (Rutherford Appleton Laboratory, Oxford, U.K.). Attendees represented academic institutions and industry. The conference programme consisted of 8 sessions followed by discussions, two invited papers and an after dinner presentation on the first full day of the conference entitled "The Future". The major session topics were: - 2½D Sketch Object Models, Matching and Geometry I Object Models, Matching and Geometry II Image Descriptions and Segmentation Applications - Hardware - Motion Associative Networks We present below a report on the lectures given at the conference.
bined together for specific tasks at a slower, higher level. Human "low-level" operations can extract edges, and recognise objects but they also use context, e.g. face recognition is very fast. Ullman went on to say that we can understand the character string "Ideal" as the word "ideal", where the first and last letters look the same but have different meanings. There seem to be fast ways of recognising shapes which are roughly ellipsoidal. He concluded by stating that this problem has applications to the fast detection of defects in printed circuit boards.
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Opening Session Visual Routines S. Ullman (Weizman Institute of Science, Israel) said that computer vision might profitably copy the human vision system, which appeared to use "low-level" fast operations which could be com-
A lvey 2.5D Sketch Project In this presentation the current structure of an experimental, integrated 2.5D sketch system was outlined. A. Blake (University of Edinburgh, Scotland, U.K.) and J. Mayhew (University of Sheffield, Sheffield, U.K.) stated that its purpose was to facilitate experimentation in integration of low-level visual competences. They described the three main components: a set of base representations, a set of knowledge sources, and the regionedge-vertex (REV) graph. In conclusion they reported that currently most of the base representations are implemented; access functions for the REV graph are in place, together with trace facilities and an experimental "consistency mainte-