Computer-aided Engineering System Research Articles

Application of model-based reasoning to the development of intelligent CAE systems

A general methodology for developing intelligent computer aided engineering (CAE) systems is presented here, based on the authors’ observation of several generic features of any CAE and a so-called “model based reasoning (MBR) approach” to knowledge engineering. In particular, a general model is proposed for the architecture of intelligent CAE systems, and MBR is incorporated into the implementation of such systems. To this end, key elements of MBR are illustrated in the context of the development of intelligent CAE systems. A successful implementation of the methodology is reported and taken as a case to explain the proposed methodology.

Mathematical models for computer simulation of electrochemical machining processes

Electrochemical machining (ECM) is an important manufacture technology in machining difficult-to-cut materials and to shape complicated contours and profiles with high material removal rate without tool wear and without inducing residual stress. This paper presents the physical and mathematical models on the basis of which of the simulation process module in the computer-aided engineering system for ECM (CAE-ECM) has been developed. Some examples of CAE-ECM System application are discussed.

CAD challenges for microsensors, microactuators, and microsystems

In parallel with the development of new technologies, new device configurations, and new applications for microsensors, microactuators, and microsystems, also referred to as microelectromechanical devices and systems (MEMS), there has arisen a growing need for computer-aided engineering and design systems. There is a wide range of design problems: process simulation, solid-body geometric renderings from photomasks and process descriptions, energetically correct simulations of behavior across multiple coupled energy domains, extraction of lumped low-order models of device behavior, optimization of geometry and process sequence, and design of full systems that include MEMS devices. Because of the computational demands of the modeling required to support full computer-aided design (CAD), there is a premium on fast and memory-efficient algorithms that help the designer, both by automating, where possible, complex sets of related tasks and by providing rapid computational prototyping at critical points in the design cycle. This paper presents an overview of the present state of the art in CAD for MEMS, with particular emphasis on the role of macromodels and test structures as part of the design environment.

Simulation of Hot Isostatic Pressing of a powder metal component with an internal core

This paper presents a finite element simulation of the thermomechanical phenomena occurring during Hot Isostatic Pressing (HIP) of a powder metal component which includes a graphite core. The thermomechanical coupling is achieved in a staggered step manner. The staggered step approach considers the coupled thermomechanical response of solids, including nonlinear effects in both the thermal and mechanical analyses. The creep behaviour of the powder material during densification is modelled using the constitutive equations of thermal elasto-viscoplastic type with compressibility. The various mechanical material properties are assumed to be functions of temperature and relative density. The mechanical solution also includes large deformation and strains. The thermal problem includes temperature and relative density dependent specific heat and thermal conductivity. The constitutive equations and relations for thermal characteristics are implemented into the implicit nonlinear finite element code, PALM2D. The simulation of the HIP process of a component with internal core is chosen as an application example. The component, injection molding tool, is produced of a hot isostatically pressed stainless tool steel with an internal cavity which is achieved by inserting a graphite core into the HIP container. To verify the result of the simulation, the geometry of the capsule and the coated core are measured both before and after pressing using a computer controlled measurement machine (CMM). The measured geometry is compared with the simulated final shapes of the container and internal core. A computer-aided concurrent engineering system (CACE) is used for the complete manufacturing process from the design of the component and finite element simulation to the inspection of the final geometry.

A Guide to CASE Tools in Support of System Architecting

ABSTRACTThe rapid pace recently established by the Computer Aided Systems Engineering (CASE) tools industry provides opportunities to constantly look ahead and challenge tools to do more in support of complex systems development. This situation also forces CASE tools users to cry out for guidance in defining tool capabilities and selecting from among the growing list of candidates. The INCOSE Systems Architecture Working Group (SAWG) has produced version 1.0 of “A Guide To CASE Tools in Support of System Architecting” (dated May 1997) to address such a need for guidance. The guide is written to give the CASE tool novice a starting point and to give the more experienced CASE tool user some considerations for advanced capabilities.

Integrating computer-aided software engineering and object-oriented systems: A preliminary analysis

Over the past several decades, the software development life cycle has encountered vast changes, and with these changes have come many obstacles. From improving performance and increasing capacity in the 1950s and 1960s to managing burgeoning complexities in the 1990s, software development has taken two roads—computer-aided software engineering (CASE) and object-oriented systems (OOS). But neither CASE nor OOS methods have fully exploited the potentials to dramatically influence software development methodologies. This paper will identify the possibility of integrating CASE and OOS to provide for a more effective model of software development, resulting in increased productivity, reduced software development costs and improved software product quality (reliability, usability and performance), documentation and system maintenance.

Frameworks of Flexible Analysis System for Integrated Computer Aided Engineering System

A designer has to analyze and evaluate product information. There is various kind of analyses which is used in design stages according to an evaluation purpose. Therefore, it is necessary to execute a lot of analyses and evaluate product information overall.In design stages, many CAE (Computer Aided Engineering) systems are introduced to execute a lot of analyses. However, a lot of analysis systems are isolated. The integration of each analysis system depends on designers. Designer has to generate huge input data and convert from huge output data to input data of another analysis. It is very important to integrate analysis systems and to integrate design system with analysis system. In order to develop Simulation Based Design system which support designing the best product by the simulation technique, design system should be integrated with various analysis systems.In this paper, I suggest implementing system modules of analysis system to integrate the analysis system flexibly. In order to make clear system modules of analysis system, I organize information and the processing function of analyses. This paper shows the frameworks to develop the flexible system, and the CAE system which can be freely assembled by combining system modules of analysis system to make the flow of analysis.

複合領域を考慮した自動構造設計システムの開発とマイクロ加速度センサ設計への応用

This paper describes a novel automated computer-aided engineering (CAE) system for multidis-ciplinary structural design. An automatic finite element (FE) mesh generation technique, which is based on fuzzy knowledge processing and computational geometry techniques, is incorporated into the system, together with a commercial FE analysis code and a commercial solid modeler. The system allows fully automated FE analyses of various physical phenomena, i. e., electrostatic analysis, stress analysis, modal analysis and so on, to be performed. An optimum design solution and/or satisfactory solutions are then automatically searched for using the genetic algorithms modified for a real search space, together with the automated FE analysis system. This CAE system is successfully applied to the shape design of a microaccelerometer based on a tunnel current concept.

Automated Integration of Enterprise Accounting Models Throughout the Systems Development Life Cycle

This paper summarizes and projects research in the field of automated software engineering as that work has been applied to the domain of accounting-centered enterprise models. In particular, we review the basic concepts and goals of the REA (Resource–Event–Agent) accounting model and speculate on its past, present, and future use as an embedded domain theory of enterprise economic activity within computer-aided systems engineering (CASE) tools. The REA CASE tools reviewed here include ones like REAVIEWS, CREASY, and REAtool that have already been built plus others like REACH, FREACC, and REAVERSE that have been specified only in theory. The entire systems development life cycle is used as a discussion vehicle to treat these tools and projected future work in an integrated way. © 1996 Wiley Periodicals, Inc.

User responses to constraints in computerized design tools (extended abstract)

This study sought to improve our understanding of user attitudes, perceptions, satisfaction and behavior in reference to constraints within computerized design tools. It also attempted to examine the differences in perspective between tool builders and tool users regarding appropriate design practices, as communicated via design tools.The study created a typology of constraints and described a set of strategies users employ in the negotiation of constraints encountered in of computer-aided systems engineering (CASE) tools. Also addressed were (a) the cognitive fit between tool users and tool builders in terms of appropriate and necessary constraints, and (b) issues of creativity in the design of computer software.An eight-page questionnaire containing 61 questions was developed by conducting structured interviews with tool users and managers, in industry. Following a pre-test, the questionnaire was administered to an international sample of tool users, tool builders and non-CASE software application developers (a control group). More than 200 questionnaires were returned (half via electronic mail) from respondents largely in North America, but also from Europe, Australia and New Zealand.Analysis followed a factorial design that evaluated the impact of normative attitudes toward and perceptions of control upon satisfaction and behavior. Most respondents reported not feeling especially encumbered with constraints in their tools, although most also reserved the right to override or work around constraints, depending upon circumstances.The study found that normative attitudes toward control have a significant impact upon behavior in response to constraints in computerized design tools. (Favorable attitudes toward control are associated significantly with conforming behavior.) It also found that perceptions of control have a significant impact upon satisfaction and behavior. (Perceptions of high control are associated significantly with low satisfaction and with resistant behavior.) No significant differences were observed between tool users and tool builders in terms of key constructs.Suggestions for future research include investigation of concerns raised by the current study, examination of similar effects in other domains (such as architectural design), and development of the potential for intelligent machine guidance in creative design activities.

CURRENT TRENDS IN REQUIREMENTS AND SPECIFICATION MANAGEMENT

ABSTRACTOver the last 5 years, Marconi Systems Technology has been involved in developing a state‐of‐the‐art software product for requirements elicitation, traceability and management, able to interface with other best‐of‐breed CASE (Computer Aided Systems Engineering) tools. The product, known as “RTM” (Requirements & Traceability Management) (MST 1996), has achieved critical worldwide acclaim and is currently in use on some of the most advanced systems under development.Through direct contact with many projects, it became clear that the different interest groups present in a company or project (from marketing to project management and systems engineers) had radically different expectations both on how they wanted to use such requirements management support and also what capabilities they as specific interest groups wanted from a requirements management tool.Two common themes appeared to be shared by these interest groups. The first was the need to move away from the realm of primitive ASCII based requirement representations into the much more powerful and comfortable review and editing environments provided by many of today's leading desktop publishing tools. The second was to have the powerful information modeling, traceability, audit trail and impact analysis capabilities of RTM “fused” into their preferred editing environments.This paper describes some of these current trends in requirements & specification management and their implementation in RTM V3.

Process and die design for multi-step forming of round parts from sheet metal

Designing process sequences for deep drawing of round cups has traditionally been a trial and error process. This paper describes a Computer Aided Engineering (CAE) system for designing process sequences and the corresponding tooling that is currently being developed at the Engineering Research Center for Net Shape Manufacturing (ERC/NSM). This system will help designers in developing and evaluating process sequences and in predicting possible problems before the manufacturing of tools and the production of parts. This will lead to substantial savings in time and costs. The CAE system consists of a rule-based design module to generate the process sequences and an analysis module based on the Finite Element Method (FEM) to predict potential problems by simulating the forming processes. This paper discusses the implementation of the rules to design process sequences as well as some aspects of the numerical simulation of the forming processes.

A computer-aided engineering system for feature-based design of box-type sheet metal parts

This paper explores the applications of feature-based representation and design in the area of design for manufacturing to incorporate the tooling and process considerations into the early stages of design. The goal of this research is to apply the concepts of feature-based design and to develop an interactive design tool that can be used to alert the designers to potential production problems, defects and failures, and to provide them with information that can be used to explore alternative design, evaluate trade-offs, and arrive at optimal designs for the given process conditions. This paper illustrates the development of a computer-aided engineering (CAE) system that was constructed using these concepts and applied to designing box-type sheet metal parts.

How Strategies Happen: A Decision-Making Framework

This multiple-case study investigates the decision to upgrade existing computer-aided design and computer-integrated engineering (CAD/CIE) systems in four international architectural, engineering, and construction (AEC) firms. Conventional methods of viewing strategy formation do not reflect the importance of dynamic elements (clients, champions, technical competence, etc.) in making strategic decisions. Four decision factors developed in this investigation—Tangent (impetus), Titanic (risk), Timing, and Technology—provide a useful vehicle to understand the strategic decision-making process and help to create a knowledge base of strategic issues within the AEC industry. The overall finding is that strategic decisions spring from many sources external to a formal planning process and that the strategy formation process is not linear. The research also identifies several ways for AEC firms to increase the effective use of CAD/CIE.

Evolutionary Steps in Expert Systems Projects

An expert system is computer software that applies human expertise to solve problems, and successful applications result in numerous, diverse benefits. Generally, projects that develop expert systems go through several important evolutionary steps and contain unforeseen events. Our longitudinal study of two successful projects, the computer-aided requisition engineering system developed at General Electric Motors and the logistics management system developed at IBM, showed that establishment of a funded project, establishment of a multi-disciplinary development team, understanding and control of data, broad user involvement, internal development of new expertise, expansion of the user base, personnel shifts and reassignment of tasks and responsibilities, and the emergence of new business opportunities are important evolutionary steps in expert systems projects. In addition, the study revealed that top management support, business benefits, and a talented multidisciplinary team were critical to implementation success in both companies.

A CAE system for micromachines: its application to electrostatic micro wobble actuator

Abstract This paper describes a new computer-aided engineering (CAE) system for micromachines 10 −6 −10 −3 m in size. An automatic finite-element (FE) mesh-generation technique, which is based on the fuzzy knowledge processing and computational geometry techniques, is incorporated into the system, together with a commercial FE analysis code, MARC, and a commercial solid modeler, DESIGNBASE. The system allows a geometry model of interest to be automatically converted to different FE models, depending on the physical phenomena of the micromachines to be analyzed, i.e., electrostatic analysis, stress analysis, modal analysis, and so on. The FE models are then automatically analyzed using the FE analysis code. Out of the whole process of analysis, the definition of a geometry model, the designation of local node patterns and the assignment of material properties and boundary conditions to the geometry model are the only interactive processes to be done by the user. The interactive operations can be processed in a few minutes. The other processes, which are time consuming and labour intensive in conventional CAE systems, are fully automatically performed in a popular engineering workstation environment. With the aid of multilayer neural networks, the present system also allows us to obtain automatically a design window in which a number of satisfactory design solutions exist in a multi-dimensional design parameter space, considering coupled multiple phenomena such as static and dynamic deformation, thermal conduction, electrostatics, and so on. This CAE system is successfully applied to evaluate an electrostatic micro wobble actuator. As a typical CAE evaluation, we identify the quantitative conditions for operating the micro wobble actuator, considering both structural and electrostatic phenomena.

A review of computer-aided Simultaneous Engineering systems

World-wide markets are becoming increasingly competitive, and in order to sustain market share organisations are developing a customer-oriented approach for designing and producing high-quality, high-value products. The philosophy of simultaneous engineering has been proposed as a potential means of improving product development practice. This philosophy involves simultaneously satisfying the functionality, reliability, manufacturability, and marketability concerns of new products in order to reduce product development time and cost, and to achieve higher product quality and value. In this paper the concept, objectives and principles of simultaneous engineering are introduced. The past and present research into computer-aided systems for the support of simultaneous engineering is present, reviewed and classified. This will both allow the current state of the art to be assessed, and enable the identification of future research that will contribute to the realisation of computer aided support for Simultaneous Engineering.

Development of Integrated CAE system for Design Ship Structure in CIM

Recently, an economic environment of industry changes for the worse in Japan. Therefore, a new strategy is necessary to get more competitive technology in design stage of ship. A new concept which is called ADDA (ADvanced Design by Analysis) is now introduced.In order to realize “Advanced Design by Analysis”, Computer Aided Engineering systems should be discussed from the standpoint of integrated system. In this paper, the following systems are integrated by using the concept of product definition system.1) System for calculation trim, stability, and so on.2) System for calculation of ship motions and wave pressure.3) System for calculation of strength for ship structure.4) System of short-term and long-term predictions for local stresses.In order to integrate those systems, some kinds of revision in product definition system which were implemented in SODAS were carried. And furthermore, new input and output generator for the respective CAE systems are made.The integrated system makes it possible to carry ADDA in a relatively short time. The actual processing time for a special ship was 20 hours. Therefore, designers who have to design a new ship are able to carry ADDA more than once by using this system.

Modelling the CASE process: empirical issues and future directions

Many current models of information system originated before the widespread use of Computer Aided System Engineering (CASE) tools. The aim of CASE is to automate part of the development process, thus increasing productivity and quality. In this paper, we assess the validity of four significant models of system development against the experiences of three CASE-based development projects. A valid model is a necessary but not sufficient basis for process improvement. The adequacy of the models in addressing the problems encountered in the projects is assessed, and a broader model of information system development is proposed, encompassing strategic planning, organizational learning and the reconciliation of alternative viewpoints.

IMPROVING THE COMPUTER WORKSTATION INTERFACE FOR ENGINEERING AND A PROPOSAL FOR USER INTERFACE STANDARDIZATION

ABSTRACTToday's product development environment needs to use many Computer Aided Engineering (CAE) tools to reduce programs technical risk and reduce product life‐cycle‐cost. The tools should also provide a basis for implementation of non‐recurring cost effective engineering processes and practices. Twenty years of research across many companies compiled data that indicates current state‐of‐the‐art CAE is not cost effective. These findings have been validated by recent financial reports. While there are many causes for such burden, the user interlace with the CAE system was determined to be a significant productivity issue. This obstacle to productivity can be removed by the implementation of a User Interface Standardization (UIS).Improvements to achieve a common user interface has fallen short of optimum results because of the lack of system engineering practices in the standardization methodology. This paper proposes the UIS and establishes the needed methodology for its success.