Showing papers on "Conceptual design published in 1996"

Seismic Design and Retrofit of Bridges

Abstract: This book should be of interest to practicing bridge designers and researchers investigating the seismic design of bridges It is appropriate for graduate courses or upper level undergraduate courses in seismic design of bridges The approach relies heavily on the principles of capacity design, where a strength hierarchy is established in a bridge to ensure that damage is controllable and occurs only where the designer intends This approach, which is well established for seismic design of buildings, has been extended and modified to reflect the special demands and characteristics of bridges Particular emphasis is placed on designing adequate displacement and ductility capacity into new bridges, with less significance placed on strength The book is developed around two alternative design strategies: the traditional force-based approach where force levels are related to acceleration spectra, with checks to ensure adequate displacement capacity exists, and the newer displacement-based design approach, where displacements are the starting point in the design Introductory chapters discuss design philosophy and its impact on the performance of bridges in recent earthquakes, seismicity and soils effects, including liquefaction, in a form facilitating understanding by structural engineers, and the importance of rational consideration, from a seismic design viewpoint, of the various structural configuration possibilities in the conceptual design phase Extensive discussion of analysis is provided in Chapter 4, with emphasis on the importance of realistic modeling assumptions and appropriate choice of analytical tools Chapters 5 to 8 provide detailed information on the design of new bridges and the assessment and retrofit of existing bridges A separate chapter is devoted to design and retrofit using seismic isolation and dissipation devices Many design and analysis examples, some quite extensive in scope, are included Design aids in the form of charts and tables are also provided An index is provided

Bringing Design to Software

Abstract: 1. A Software Design Manifesto. 2. Design of the Conceptual Model. 3. The Role of the Artist-Designer. 4. Design Language. 5. The Consumer Spectrum. 6. Action-Centered Design. 7. Keeping It Simple. 8. The Designer's Stance. 9. Reflective Conversation with Materials. 10. Cultures of Prototyping. 11. Footholds for Design. 12. Design as Practiced. 13. Organizations for User-Centered Design. 14. Design for People at Work. Reflection. Bibliography. Index.

Supporting conceptual design based on the function-behavior-state modeler

Abstract: The relative significance of conceptual design to basic design or detail design is widely recognized, due to its influential roles in determining the product's fundamental features and development costs. Although there are some general methodologies dealing with functions in design, virtually no commercial CAD systems can support functional design, in particular so-called synthetic phase of design. Supporting the synthetic phase of conceptual design is one of the crucial issues of CAD systems with function modeling capabilities. In this paper, we propose a computer tool called a Function-Behavior-State (FBS) Modeler to support functional design not only in the analytical phase but also in the synthetic phase. To do so, the functional decomposition knowledge and physical features in the knowledge base of the modeler, and a subsystem Qualitative Process Abduction System (QPAS) play crucial roles. Modeling scheme of function in relation with behavior and structure and design process for conceptual design in the FBS Modeler are described. The advantages of the FBS Modeler are demonstrated by presenting two examples; namely, an experiment in which designers used this tool and the design of functionally redundant machines, which is a new design methodology for highly reliable machines, as its application.

Method and system for creating and validating low level description of electronic design

Abstract: A methodology for generating structural descriptions of complex digital devices from high-level descriptions and specifications is disclosed. The methodology uses a systematic technique to map and enforce consistency of the semantics imbedded in the intent of the original, high-level descriptions. The design activity is essentially a series of transformations operating upon various levels of design representations. At each level, the intended meaning (semantics) and formal software manipulations are captured to derive a more detailed level describing hardware meeting the design goals. Important features of the methodology are: capturing the users concepts, intent, specification, descriptions, constraints and trade-offs; architectural partitioning; what-if analysis at a high level; sizing estimation; timing estimation; architectural trade-off; conceptual design with implementation estimation; and timing closure. The methodology includes using estimators, based on data gathered over a number of realized designs, for partitioning and evaluating a design prior to logic synthesis. From the structural description, a physical implementation of the device is readily realized. Techniques are described for estimating ancillary parameters of the device (such as device cost, production speed, production lead time, etc.), at early, high level stages of the design process (e.g., at the system, behavioral, and register transfer level stages). The techniques can be applied to optimize the design characteristics other than measurable physical characteristics, such as those deriving from project time and cost constraints.

Function–behavior–structure paths and their role in analogy-based design

Abstract: In many creative design processes, cross-domain knowledge is required to inspire the new design result. Thus, in knowledge-based design, how we represent the cross-domain knowledge becomes a key issue. In this paper, we present a formalism for design knowledge representation. By analyzing function representation in different design domains, from graphic design and industrial design to architectural and engineering device designs, we find that although the focus of each kind of design is different, the function representation can be generalized into a small number of categories. This formalism can be used in an explorative model of design by analogy, where designs from different design domains are sources to help produce a new design.

Modeling Design Exploration as Co-Evolution

Abstract: Most computer-based design tools assume designers work with a well defined problem. However, this assumption has been challenged by current research. The explorative aspect of design, especially during conceptual design, is not fully addressed. This paper introduces a model for problem-design exploration, and how this model can be implemented using the genetic algorithm (GA) paradigm. The basic GA, which does not support our exploration model, evaluates individuals from a population of design solutions with an unchanged fitness function. This approach to evaluation implements search with a prefixed goal. Modifications to the basic GA are required to support exploration. Two approaches to implement a co-evolving GA are presented and discussed in this paper: one in which the fitness function is represented within the genotype, and a second in which the fitness function is modelled as a separately evolving population of genotypes.

Artificial Intelligence in Design ’96

Abstract: Representations in design design objects genetic algorithms/genetic programming in design case-based design reuse of designs grammars in design design spaces learning in design distributed design rules, models and theories in design conceptual design spatial and layout planning in design creativity and innovation in design.

Functional descriptions used in computer support for qualitative scheme generation—“Schemebuilder”

Abstract: With increased pressures coming from global competition and requirements for greater innovation in product development, designers are hard pressed to deliver designs of higher quality and variety using a repertoire of technological options from different disciplines. This interdisciplinary product development approach has not only removed many of the traditional constraints to design but has now given designers a much wider freedom of choice as to the best solution to a design problem. The focus of this paper is a knowledge-based design environment called Schemebuilder, which is a comprehensive and integrated suite of software tools aimed at supporting the designer in the rapid development of product design models in the conceptual, through embodiment stages of design. Illustrated is the use of the software tools in the qualitative generation of alternative schemes, by application of stored working and decomposition principles in the development of a function-means tree-like information structure. With mechatronic product development as the main theme, this paper describes a closely integrated methodology that incorporates a bond graph approach to continuous-time energetic systems and high-level Petri nets for the rigorous description of discrete-time information systems. Additionally, a technique is suggested for the decomposition of free format statements of need into the rigorously defined design context and required functions, which form the starting point of the function-means development process.

Case-based conceptual design information server for concurrent engineering

Abstract: Conceptual design requires processing information from diverse sources in order to define the functional requirements, operating constraints, and evaluation criteria pertinent to accomplishing a prescribed goal.Historically, the design process focused on the functionality of an artifact for the end customer. Concurrent engineering broadens this focus to account for the concerns of `customers' not previously considered --those along the entire life cycle of an artifact, i.e. marketing, design, manufacture, distribution, operation and disposal. Expanding the design focus to include all of these customers places far greater informationaldemands on the designer. Case-based reasoning applies experience stored in a computerized form to solving similar problems in slightly altered contexts. It has been applied successfully to routine design whereboth the form and the content of design information can be encoded symbolically and manipulated using artificial intelligence techniques. Concurrent conceptual design presents unique problems for such anapproach because design information must be considered at many levels of abstraction and from many viewpoints.We describe an approach that provides the designer with case-based conceptual design information stored in the richly expressive medium of hypermedia (hypertext incorporating multimedia). Design cases ofindustry `best practices' in concurrent engineering are indexed to provide access through multiple interfaces, allowing the user to browse, explore, or pinpoint design case information. The Conceptual DesignInformation Server (CDIS) is implemented using emerging internet standards, such as those associated with the World Wide Web (WWW) and Wide Area Information Service (WAIS), coupled to a robustStructured Query Language (SQL) database and traditional cad packages.

An approach to functional synthesis of mechanical design concepts : Theory, applications, and emerging research issues

Abstract: Conceptual design is an early stage in the design process that involves the generation of solution concepts to satisfy the functional requirements of a design problem. Usually, there are many solutions to a design problem; therefore, there is scope for producing improved designs if one could explore a solution space larger than is presently possible. An approach would be to use the computer to synthesize a wide variety of concepts for a given problem, and allow designers to explore these before developing the most promising ones. Adopting a research approach based on developing basic representations, knowledge base, and reasoning procedures adequate for synthesizing concepts of existing devices and mechanisms, a computer program for synthesis of solutions to a class of mechanical design problems has been developed. For a given design problem, the program can produce an exhaustive set of solution concepts, in terms of their topological and spatial configurations, which can then be explored by designers. The program has been tested in two ways: (1) by comparing the candidate solutions produced by the program with those produced by designers in two real design case studies, and (2) by using three experienced designers to evaluate the solutions, generated by the program, for their novelty and usefulness. This paper presents the theoretical basis, research method, the theory and implementation of the synthesis approach. Also, the results of the above case studies and evaluations, and a discussion of further issues highlighted by the evaluations are presented.

Discourse model for collaborative design

Abstract: A Discourse Model, including a structure and a process, is developed that provides software support for collaborative engineering design. The model shares characteristics of other design systems in the literature, including frames, constraints, semantic networks, and libraries of sharable design objects. It contributes a new model for conflict-aware agents, dynamic identification and dissemination of agent interest sets, a virtual workspace language, automatic detection of conflict, and a unique protocol for negotiation that ensures that interested agents have an opportunity to participate. The model is implementation independent and applicable to many research and commercial design environments currently available. An example scenario is provided in the architecture/engineering/construction domain that illustrates collaboration during the conceptual design of a fire station.

Industrial Applications of Chemical Process Synthesis

Abstract: Systematic approaches for the invention of conceptual chemical process designs have been proposed and discussed for more than twenty-five years. During that same time, the importance of front-end engineering, especially conceptual design, to product quality, health and safety, environmental impact, energy consumption, operability, capital and operating costs, and overall competitiveness has become ever more apparent. A number of process synthesis frameworks, approaches, methods, and tools have now been developed to the point of industrial application. This chapter describes a framework for the industrial chemical plant innovation process, showing how process synthesis fits into that structure and how that framework has in turn influenced the development of systematic process synthesis methods. It also describes a number of industrial case studies in which process synthesis techniques have been successfully applied to the conceptual design of total process flowsheets, as well as to specific design subproblems including heat-integrated distillation trains, multiple-effect distillation, and the separation of azeotropic systems. Typical energy savings of 50% and net present cost reductions of 35% have been achieved in industrial practice using systematic process synthesis methodologies. Even greater benefits are expected to be realized as the next generation of approaches currently being developed is transferred to industry.

DeMAID/GA an Enhanced Design Manager's Aid for Intelligent Decomposition

Abstract: Many companies are looking for new tools and techniques to aid a design manager in making decisions that can reduce the time and cost of a design cycle. One tool is the Design Manager's Aid for Intelligent Decomposition (DeMAID). Since the initial public release of DeMAID in 1989, much research has been done in the areas of decomposition, concurrent engineering, parallel processing, and process management; many new tools and techniques have emerged. Based on these recent research and development efforts, numerous enhancements have been added to DeMAID to further aid the design manager in saving both cost and time in a design cycle. The key enhancement, a genetic algorithm (GA), will be available in the next public release called DeMAID/GA. The GA sequences the design processes to minimize the cost and time in converging a solution. The major enhancements in the upgrade of DeMAID to DeMAID/GA are discussed in this paper. A sample conceptual design project is used to show how these enhancements can be applied to improve the design cycle.

From Symbol to Form: A Framework for Conceptual Design

Abstract: This paper presents the design of a software framework for conceptual design. It develops an approach to mapping an evolving symbolic description of design into a geometric description. The distinct elements of the symbol-form mapping are: (a) deriving spatial relationships between objects as a consequence of the functional relationships; (b) instantiating alternative feasible solutions subject to these relationships; and (c) presenting the evolving descriptions of geometry. Computational support for each of these elements is provided within a conceptual design framework. The paper presents components of the framework, explicitly identifies interactions between these components, and explains how these interactions are developed into an integrated framework. It presents the rationale for the design decisions made in the framework. An example is presented to clarify the approach adopted. The applicability of the approach is then discussed.

A formal model for role-based access control with constraints

Abstract: The aim of this work is to give a formal foundation to the notion of role-based access control through the introduction of a new model and the formal specification of its semantics. The proposed model takes into account all the main topics currently under discussion in this area, including constraints and separation of duties. Moreover, it is suitable both for conceptual design purpose and direct implementation within real systems.

A Comparative Analysis of the Theory of Inventive Problem-Solving and the Systematic Approach of Pahl and Beitz

Abstract: This paper presents a comparative analysis of two designmethodologies; the Theory of Inventive Problem-Solving (TIPS)and the systematic approach of Pahl and Beitz (SAPB).The methodologies are compared with respect to a numberof aspects; similarities and differences are highlighted. It is thensuggested that a more powerful methodology may result if themethodologies are unified and that such a unification should useSAPB as an underlying design process model being comple-mented by TIPS elements at certain points. This is because theSAPB has a wider scope as a design process model, covering thewhole process from task clarification to detail design andcomponent as well as systems design, whereas TIPS featuressome very useful elements (engineering systems evolution laws,standards and principles) that are not included in the SAPB.1 INTRODUCTIONWithin design science, a large number of design methodolo-gies have been developed. The distinctions between thesemethodologies are not clear: they overlap and use differentdefinitions of key concepts such as function. Reviews of designmethodologies (Bjarnemo, 1983; Finger and Dixon, 1989) haveresulted in the classification of various methodologies. However,the classifications have not led to the development of morepowerful methodologies or in a reduction of the number ofcompeting methodologies, although many methodologies havesimilar aims, structure and inherit design knowledge. In thispaper, we apply a research method, suggested by Kaulio andRosenblad (1995), that hypothesizes that a pair-wiseassessmentof design methodologies may be a more effective approachtowards these goals, by enabling a more focused analysis of theprocess steps and concepts of the methodologies.The method can be used for a comparative analysis of twomethodologies, given that these propose similar actions andprocess steps and have been developedindependently. Themethodologies must further have the same goal, describe thesame phenomena at the same level of resolution, and be articu-lated to such a degree that a comparison is fruitful. This analysiswill illuminate the similarities and differences between themethods. This enables an investigation into the possibilities ofunifying the methodologies.Kaulio and Rosenblad applied their approach in a study oftwo methodologies for requirements engineering, QualityFunction Deployment (QFD) and the “User-Oriented ProductDevelopment”. We are here focusing on conceptual design. Themethodologies that are studied are the Theory of InventiveProblem-Solving (TIPS) (Altshuller, 1988) and the systematicapproach of Pahl and Beitz (SAPB) (1995). These methodolo-gies were selected for the following reasons:1. The methodologies aim to facilitate the creation of newproducts and the improvement of old products.2. Both methodologies emphasize the importance of the knowl-edge of physical effects to solve technical problems.3. The methodologies have different backgrounds and weredeveloped independently. TIPS was developed in the SovietUnion with a very limited knowledge of other methodolo-gies but is based on a large empirical knowledge base in theform of patents. No other methodology is based on that kind

Metrics for Assessing Design Freedom and Information Certainty in the Early Stages of Design

Abstract: Our primary focus in this paper is on open engineering systems which are readily adaptable to changing design requirements Designing an open engineering system allows a family of products to be developed around a common baseline model This entails increasing design freedom and design knowledge during the early stages of design Toward this end, developing ranged sets (as opposed to points sets) of top-level design specifications provides a means to improve system flexibility by increasing design knowledge while maintaining design freedom Consequently, our secondary focus in this paper is on metrics for assessing the design freedom and information certainty associated with a ranged set of top-level design specifications As a demonstration, these metrics are applied to an example problem, namely, the conceptual design of a family of aircraft Our emphasis in this paper is on introducing open engineering systems and metrics for design freedom and information certainty, not on our example, per se

Road Vehicle Aerodynamic Design: An Introduction

Abstract: This book provides an introduction to road vehicle aerodynamic design for students, engineers and designers working in the automotive field. A description of the basic mechanisms of lift and drag production on road vehicles (domestic cars, commercial vehicles and track racing cars) is given together with the principles of drag reduction and the generation of downforce. It explains the physical principles and the methods of experimental measurement that can be used in the study of road vehicle aerodynamics. Many of the experimental studies conducted in the previous two decades are described. Wind tunnel and road testing methods are considered and a short introduction to computational fluid dynamics techinques is included. Using the information provided, the reader should be able to attempt a low-drag conceptual design, and should be able to assess the reasons for aerodynamic defects in an existing shape.

A rapid geometry modeler for conceptual aircraft

Abstract: A new, highly interactive, parameter-based aircraft modeler has been developed for use in conceptual design. The Rapid Aircraft Modeler (RAM), was developed to generate detailed 3-D geometric models quickly and easily. The models allow a visual inspection of the geometry parameters used in the conceptual aircraft design and optimization process. Fast and accurate geometry modeling also allows the designer to use more complex analysis methods earlier in the design process and reduces reliance on empiricism in conceptual design.

Information handling behavior of designers during conceptual design: three experiments

Abstract: iii I certify that I have read this dissertation and that in my opinion it is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. I certify that I have read this dissertation and that in my opinion it is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. I certify that I have read this dissertation and that in my opinion it is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Abstract This dissertation demonstrates an iterative Observe->Analyze->Intervene, design research methodology to incrementally improve the understanding and the support of information handling in the conceptual design process. It reports on two observational studies, based on the verbal protocol method, and an information management service. The first observational study is a detailed analysis of the questioning behavior of designers to understand information needs during a redesign task. This resulted in the design information framework, which classifies information that should be captured during a design process for effective reuse at a later date. This framework was used to develop an information management service called Dedal, a tool for indexing, modeling and retrieving design information. Observations from deployment and usage of Dedal lead to the second observational study. This was a study of the information handling behavior of individual designers doing short conceptual design tasks. This study resulted in the Information Handling Framework (IHF). The IHF is a framework for understanding information handling behavior during conceptual design. Some key observations from the use of this framework are: • designers move frequently between different types of information (on an average every 13 seconds), • they handle information about upto 40 concepts in one minute, • their ability to work fluidly and with ease while handling all types of information is essential during the conceptual design process, and • the points of transition between different information types are critical from the viewpoint of computational support. Deeper understanding of the information handling behavior is explained by means of detailed qualitative and quantitative results. The implications of these results towards the improvement in the understanding of the conceptual design process and the recommendations on the development of intuitive and integral information handling services are discussed. v Acknowledgements

An Experimental Evaluation of Design Information Reuse During Conceptual Design

Abstract: SUMMARY This paper presents the results of an experimental case study conducted to evaluate the reuse of design information during the conceptual design phase The goal of this study was to determine the usefulness of design history information and to establish the sneed for providing the conceptual level design information for future use Five design engineers were given a task of product redesign to satisfy new customer requirements The scope of the redesign was limited to generating new concept( S) using the old design information We found that about 50% of the queries made by the subjects were related to the conceptual stage information from the past design effort We also found that about 70% of the old design information was useful during redesign

Landing Gear Integration in Aircraft Conceptual Design

Abstract: The design of the landing gear is one of the more fundamental aspects of aircraft design. The design and integration process encompasses numerous engineering disciplines, e.g., structure, weights, runway design, and economics, and has become extremely sophisticated in the last few decades. Although the design process is well-documented, no attempt has been made until now in the development of a design methodology that can be used within an automated environment. As a result, the process remains to be a key responsibility for the configuration designer and is largely experience-based and graphically-oriented. However, as industry and government try to incorporate multidisciplinary design optimization (MDO) methods in the conceptual design phase, the need for a more systematic procedure has become apparent. The development of an MDO-capable design methodology as described in this work is focused on providing the conceptual designer with tools to help automate the disciplinary analyses, i.e., geometry, kinematics, flotation, and weight. Documented design procedures and analyses were examined to determine their applicability, and to ensure compliance with current practices and regulations. Using the latest information as obtained from industry during initial industry survey, the analyses were in terms modified and expanded to accommodate the design criteria associated with the advanced large subsonic transports. Algorithms were then developed based on the updated analysis procedures to be incorporated into existing MDO codes.

Conceptual design of helicopters via genetic algorithm

Abstract: The genetic algorithm (GA) is a computational model of natural selection and reproduction displayed by biological populations. The capabilities of GAs as search and optimization methods make them well suited to perform conceptual design tasks. A GA has been developed and combined with an industry standard sizing code specifically for helicopter conceptual design. This GA-based program was used to generate conceptual designs for three helicopter missions. Results of these efforts are discussed, providing insight into the ability of the GA to perform helicopter conceptual design.