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ASME 1994 International computers in engineering Conference and Exhibition, CIE 1994 and the ASME 1994 8th Annual Database Symposium collocated with the ASME 1994 design Technical Conferences

作者： Wang, J.H. Wu, J.K. Department of Mechanical Engineering Center for Computer Aided Design University of Iowa Iowa CityIA United States

ISBN: (纸本)9780791812815

This paper (1) introduces Natural Assembly Relationships (NARs) to model assembly constraints between parts and (2) analyzes the constraint relationships that are defined using NARs for parameterized mechanical assemblies. The NARs are expressed as first order predicates using primitive features as arguments, such as planar and cylindrical surfaces. The concept of Basic Parameters Set is introduced as the design parameters in CAD systems, which, together with a set of form feature constraint relationships, maintains maximal consistency with original design meanings. Based on NARs, part parameters, and primitive features, design parameter chains can be constructed for closed loop assemblies. From these chains, constraint equations can be derived, which are the basis for change propagation and information management for mechanical system design. © 1994 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Chains

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Experimental validation of stochastic performance models of general layered task systems

Experimental validation of stochastic performance models of ...

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23rd International Conference on Parallel Processing, ICPP 1994

作者： Tayyab, A.B. Kuhl, J.G. Center for Computer Aided Design Department of Electrical and Computer Engineering University of Iowa Iowa City IA 52242-1000 United States

Performance analysis of synchronization mechanisms for simple layered task systems has recently been reported. In this paper, we develop and validate performance models for general layered task systems which are applicable to a wider range of synchronization mechanisms and parallel task systems. Synchronization mechanisms considered include both strong (barrier) synchronization and weak (partial) synchronization. The models explicitly consider overheads due to synchronization waiting time and contention for shared software and hardware resources. The models are solvable for a number of commonly used task computation time distributions and are experimentally validated on two different shared-memory multiprocessors. It is shown that the task computation behavior, the amount of intertask dependencies, synchronization overheads, and throughput of the processor-memory interconnection network interact in a multi-dimensional, but predictable, way to impact overall performance. Approximate and asymptotic models are used to demonstrate these relationships, in both qualitative and quantitative terms. © 1994 IEEE.

关键词： Synchronization

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Second-order shape design sensitivity analysis of 3-D elastic solids

Second-order shape design sensitivity analysis of 3-D elasti...

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5th Symposium on Multidisciplinary Analysis and Optimization, 1994

作者： Choi, Kyung K. Chen, Chin-Jung Department of Mechanical Engineering Center for Computer Aided Design The University of Iowa Iowa CityIA52242 United States

A second-order shape design sensitivity analysis (DSA) method for three-dimensional linear elastic solids is derived, using a continuum approach and the material derivative idea. To compute second-order shape design sensitivity, a shape design acceleration field is defined, which is similar to the shape design velocity field used in first-order shape DSA. Both the direct differentiation and hybrid methods are presented in this paper. Shape changes are treated for both loaded and traction-free boundaries. A numerical method, which can be implemented using established finite element analysis codes, is developed to demonstrate feasibility and accuracy of the proposed second-order shape DSA method. In order to avoid inaccuracy of finite element analysis results on the boundary for computation of design sensitivity, a domain method is developed in which design sensitivities are expressed as domain integrals. © 1994 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Finite element method

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Comparison between finite‐element and traditional procedures for the prediction of busbar behaviour

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European Transactions on Electrical Power 1995年第4期5卷 233-238页

作者： Bottauscio, O. Chiampi, M. Chiarabaglio, D. Tartaglia, M. Dr. Oriano Bottauscio (1961). IEEE. AEI received the degree in Electrotechnical Engineering from the Polytechnic of Turin/ltalyin 1985.Since 1987 he has been working as a Scientist Researcher in the Short-circuit Laboratory of the Electromechanics Department of the Istituto Elettrotecnico Nazionale (EN) Galileo Femris of Turin. His fields of interest include the analysis of the electromagnetic fields with particular reference to the simulation of the behaviour of electric contacts and the calibration of ELF field meters. (EN “Galileo Ferraris” Dep. Electromechanics Corso M. d'Azeglio42 I- 10 125 Torinofltaly T +39 11/3 9 19777. Fax +39 11/65076 11) Prof. Mario Chiampi (1947) received the degree in Electrotechnical Engineering from the Polytechnic of Turin/Italy in 1973. He was employed as Research Scientist in the Istituto Elettrotecnico Nazionale (IEN) “Galileo Ferraris” of Turin until 1987. He is currently Professor at the Polytechnic ofTurin. His research activities are numerical methods for rlectromagnetic field analysis and computer aided design of electrical devices. (Dipartimento Ingegneria Elettrica Industriale - Politecnico di Torino corso Duca degli Abruui 24 1-10129 Torinofltaly T +39/I 1 5647 142 Fax +39/11 5647 199) Dr. Daniela Chiarabaglio (1964) received the degree in mathematics from the University of TurinAtaly in 1987. She is currently employed as Research Scientist in the Electromechanics Department of the Istituto Elettrotecnico Nazionale (IEN) “Galileo Ferraris” of Turin. Her research activities include both theoretical studies on electromagnetic field formulations and their application to electrical devices by means of numerical techniques. (Istituto Elettrotecnico Nazionale “Galileo Ferraris” corso M. d'Areglio 42 1-10125 TorinoAtaly T+39/11 3919776 Fax+3911-6507611) Prof. Michele Tartaglia (1948) received the degree in Electrotechnical Engineering from the Polytechnic of TunnAtaly in 197 1. In 1973 he joined the Istituto Elettrotecnico Nazionale (EN) “Galileo Ferraris” of T

This paper investigates the multiconductor busbar behaviour under AC conditions with the aim of comparing the predictions of traditional circuit models with a more accurate analysis based on the electromagnetic field computation. This analysis employs a two‐dimensional finite‐element technique including eddy‐current effects. In linear systems this approach leads to a circuit model described by an impedance matrix, while, in presence of saturable media, field and circuit equations are simultaneously solved by a voltage‐driven field formulation. The paper analyses the behaviour of two different busbar systems when a short‐circuit current flows through them;the results obtained by the proposed approach are compared with those deduced according to the methods suggested by the IEC Standards and by the symmetrical components. Copyright © 1995 John Wiley & Sons, Ltd.

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Buckling design sensitivity analysis for frame structures

Buckling design sensitivity analysis for frame structures

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5th Symposium on Multidisciplinary Analysis and Optimization, 1994

作者： Chang, Kuang-Hua Duan, Wei Choi, Kyung K. Center for Computer Aided Design Department of Mechanical Engineering College of Engineering The University of Iowa Iowa CityIA52242 United States CAE Research and Development United States

In this paper, a continuum buckling design sensitivity analysis (DSA) method for a general linear frame structure that is formulated as a simple eigenvalue problem is proposed. Both sizing and configuration design variables are considered for DSA. The proposed continuum method can support general frame structure constructed of trusses or beams. Current buckling DSA methods that have been published in the literature, such as methods implemented in MSC/NASTRAN V67, assume that the axial forces in the members of the structure are independent of design changes. This assumption is valid only for sizing design applications of statically determinate structures, where changes of member cross sections do not change distribution of axial forces in the structure. The proposed continuum DSA method excludes such an assumption. Using the continuum approach, there is no need to take derivatives of the finite element matrix equation for sensitivity analysis. As a result, buckling DSA can be evaluated outside the finite element analysis (FEA) codes using the continuum method. Examples are given to demonstrate the proposed continuum DSA method, using FEA results from both ANSYS and MSC/NASTRAN. Also, the buckling DSA method in MSC/NASTRAN V67 is investigated, the results of which are compared to those of the proposed continuum DSA method. © 1994 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Buckling

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design sensitivity analysis of NVH of vehicle body structure

Design sensitivity analysis of NVH of vehicle body structure

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5th Symposium on Multidisciplinary Analysis and Optimization, 1994

作者： Wang, Semyung Hung, Hsien H. Hwang, Hsiu Y. Park, Youngho Choi, Kyung K. Kulkarni, Hari Center for Computer-Aided Design and Department of Mechanical Engineering The University of Iowa Iowa CityIA52242 United States Alpha Simultaneous Engineering Ford Motor Company DetroitMI48241 United States

A continuum design sensitivity analysis (DSA) of noise, vibration, and harshness (NVH) of vehicle body structure is developed for weight optimization of body structure. Vehicle body structures are modeled using MSC/NASTRAN and include warped plate elements and general cross-sectional beam elements with an offset effect. A variational approach is used to obtain the continuum design sensitivity formulation. The thickness of the plate and nonprincipal section parameters of the beam are selected as design variables. A numerical implementation method of continuum DSA is developed by postprocessing analysis results from the established finite element analysis (FEA) codes to obtain design sensitivity of NVH. The numerical method has been tested using a large-scale concept and detailed passenger vehicle models. design sensitivity results are validated using reanalysis results. The numerical method has been proven to be very efficient. Also, optimized vehicles are manufactured to validate the simulation-based design methodology. © 1994 by the authors. Published by the American lnstitute of Aeronautics and Astronautics, Inc.

关键词： Numerical methods

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Audible noise in speed‐controlled inverter‐fed medium‐sized induction motors

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European Transactions on Electrical Power 1995年第1期5卷 5-13页

作者： Muster, J. Budig, P.K. Belmans, R. Geysen, W. Sattler, Ph.K. Jorg Muster (1955) studied Electrical Engineering at the Technische Hochschule Karl-Mm-StadtlGerrnany from 1974 to 1978. Till 1985 he was Assistant at the chair of Electrical Machines and Drives absolved with promotion about losses and torques of inverter supplied AC machines. From 1985 until 1988 he worked for a tool-machine factory developing high-speed AC drives. Since 1988 he is Scientific Assistant at the chair of Electrical Machines and Drives at the Technische Universität ChemnitdGermany. (TU ChemniWZwickau Dezernat 5.0 Technologietransfer Carolastr. 8 D-09 I l l Chemnitd Germany T +*** Fax +49371/686240) PeW-KlaUs Budig (1928) studied Electrical Engineering at the Technische Hochschule Dresden/Germany from 1948 till 1952. For two years he was Assistant at the chair of Electrical Machines and Drives. From 1954 he was with Sachsenwerk Dresden. He was involved in research and development of amplidyne three-phase commutator-machines DC and AC traction motors thyristor-supplied traction motors. For some years he was Chief Technologist and finally Chief Engineer. At this time he is planning the production of new types of electrical machines like hermetic-motors rolling-mill motors. hydrogenerators and fractional horsepower induction motors. 1966 he got a call as a Professor to theTechnical University at Chemnitz/Germany. His research activities are three-phase linear motors thyristor-supplied DC motors. electric cars. computation of magnetic fields multi-motor AC drives high precision drives for the submicrorneter-range. magnetic bearing and high speed AC drives. (TU ChemnitdZwickau Fachbereich Elektrotechnik Carolastr.8 D-0911 l ChemnitdGermany T+49371/5613323 Fax +49371/5613361) Ronnie J. M. Belmans (1956) received the M.Sc. degree in Electrical Engineering from the Katholieke Universiteit LeuvenBelgium in 1979 the Ph.D. degree from the same university in 1984 and the Special Doctorate in 1989. From 1979 to 1985 he was a member of the staff of the Katholieke Universiteit Leuven. Currently

The audible noise produced by three‐phase, squirrel‐cage induction motors, is caused by the space harmonics of the flux‐density distribution in the air gap of the machine. When the motor is supplied by a frequency inverter in order to control the speed, time harmonics in both current and voltage are present, yielding new components in the audible noise spectrum. In the paper, a number of motor‐inverter combinations are compared for medium‐sized induction motors (90 kW). As a reference case, the motors are supplied with a generator, delivering a variable frequency without harmonics. Theoretical explanations for the increase of the audible noise level and the additional frequency components are given. Copyright © 1995 John Wiley & Sons, Ltd.

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Behavioral test generation using mixed integer nonlinear programming

Behavioral test generation using mixed integer nonlinear pro...

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IEEE International Test Conference

作者： R.S. Ramchandani D.E. Thomas SRC-CMU Center for Computer-Aided Design Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

This paper describes a novel technique to generate test vectors for single stuck-at faults using the behavioral description of the circuit function and the mapping from the behavior into the hardware that implements it. The test vector generation problem is formulated as a mixed integer nonlinear programming (MINLP) problem, and the test vectors are obtained by solving a series of MINLPs. The technique has been implemented and results from this approach show an order of magnitude speed up in test generation compared to existing gate-level sequential test generation tools.

关键词： Circuit testing Circuit faults Hardware design automation Sequential analysis System testing Logic testing Registers Software testing design engineering

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A CORDIC based programmable DXT processor array

A CORDIC based programmable DXT processor array

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International Conference on VLSI design

作者： V.K. Anuradha V. Visvanathan Electrical Communication Engineering Department Indian Institute of Science Bangalore India Supercomputer Education and Research Centre Indian Institute of Science Computer-Aided Design Laboratory Bangalore India

A CORDIC based processor array which can be programmed by switch setting to compute the Discrete Hartley, Cosine or Sine Transforms or their inverses is described. Through a novel formulation of the transform computations in the CORDIC framework, N-point transforms are mapped on to a linear array of /spl lsqb/N/2/spl rsqb/+1 CORDIC processors with minimal control overhead to incorporate the programmability.< >

关键词： Discrete transforms Discrete cosine transforms DH-HEMTs Switches computer architecture Integrated circuit interconnections Arithmetic Very large scale integration Equations Communication switching

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THE PARALLEL computation OF SOLUTIONS TO ELECTROSTATIC PROBLEMS USING MULTIGRID TECHNIQUES

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1994年第1期7卷 69-74页

作者： WARING, LC ROONEY, N STEWART, A FUSCO, VF Department of Computer Science The Queen's University of Belfast Belfast BT7 1NN Northern Ireland U.K. Lionel C. Waring obtained his B.Sc. (1967) and his Ph.D. (1971) in Electrical Engineering at the Queen's University of Belfast. A short period with Short Bros. and Harland was followed by an appointment in 1972 to Queen's University Chemistry Department where he was in charge of the Mass Spectrometry and Nuclear Magnetic Resonance facilities. In 1987 he was appointed Senior Research Officer in the Department of Computer Science Q.U.B. and in 1993 to a lectureship in the same Department. Department of Electrical and Electronic Engineering. Vincent F. Fusco was educated at the Queens University of Belfast where he obtained the degree of Ph.D. He worked as a research engineer on short-range radar and radio telemetry systems from 1982 to 1984. He is currently Reader in Microwave Communications in the School of Electrical Engineering and Computer Science The Queens University of Belfast. His current research interests include non-linear microwave circuit simulation and concurrent techniques for electromagnetic field problems. He has published a number of research papers in these areas and is the author of Microwave Circuits Analysis and Computer Aided Design Prentice-Hall 1987. Dr Fusco is a Chartered Electrical Engineer and a Member of the Institution of Electrical Engineers.

The application of multigrid techniques to the computation of the static solutions of electromagnetic field problems governed by Laplace's equation is described. This technique is compared with the conventional successive over-relaxation (SOR) method for solving finite difference problems. In contrast to SOR, the number of iterations of multigrid needed to achieve convergence is largely independent of the grid size. It is shown that the relative performance of multigrid is excellent on large grids where the number of iterations of SOR needed to achieve convergence becomes prohibitively large. The technique is illustrated by applying a parallel implementation of multigrid to find a quasistatic solution of a boxed microstrip problem.

关键词： Electrostatics

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