Constraint-based functional design verification for conceptual design

In the early stages of mechanical product design, designers not only need to determine the physical structure of the design, but also need to verify that the design functions properly with the allowable values or ranges of values of the relevant design attributes. Existing work on design verification is either aimed at specific design problems, which are generally carried out at the downstream design stages, or aimed at deriving design behavior using a behavioral simulation approach. Functional design verification has largely been neglected by the research society. To tackle this problem, we propose a generic constraint-based approach that is based on a comprehensive functional design model. A number of strategies are proposed for the approach, including strategies for design variables reduction, variable dependency graph development, constraint propagation, and dynamic verification of a design over an assigned set of attributes (variables). The approach is implemented as part of a functional modeling design environment. A simple design verification case is presented to illustrate our approach.     

Collaborative optimization with disciplinary conceptual design

For the first time, a multilevel optimization approach with disciplinary conceptual design is demonstrated. Collaborative optimization is used to decompose an example bridge design problem among two groups of designers – a superstructure design group and a deck design group. The disciplinary groups are allowed to search over different design concepts and formulate the design variables and constraints for each. The autonomy of the two groups is managed by a system-level group which insures that overall system objectives are met and coupling is properly accounted for. Even though discrete conceptual design occurs within the disciplinary groups, a continuous gradient-based optimization algorithm is used at the system level. The procedure was started from a nonoptimal concept, and converged to the optimal concept. Received September 9, 1999     

Intelligennt systems approach to conceptual design

In mechanical system design, the Integrated Computer Aided Design (ICAD) technology has evolved into a new generation of design techniques. It also paves the way for implementing Computer Integrated Manufacturing (CIM) systems. However, the key issue to accomplish the objective in ICAD is the conceptual design automation. Conceptual design is a creative activity and an important decision making during overall product design to reduce energy consumption, to increase raw materials utilization, to obtain more profits, to reduce environmental effects of effluents, and to ensure flexibility, operability, controllability, and safety of manufacturing processes. Therefore, the quality of conceptual design determines the final quality of products and profit of plants. In this article, we first introduce the fundamentals and characteristics of conceptual design. Then, a general problem-solving strategy and methodology to implement conceptual design automation are proposed. an Integrated Distributed Intelligent Design Environment (IDIDE) for developing conceptual design expert systems is presented. Fundamental principles, system organization, and implementation techniques are discussed. Finally, an application case for wheel loader design is studied. © 1995 John Wiley & Sons, Inc.     

Decision support for conceptual bridge design

A knowledge based, decision support tool for the conceptual design of bridges is described. The system incorporates a restructured version of a knowledge base (KB) for conceptual bridge design. The restructuring results in a KB which can be readily altered and extended by system users who are not expert knowledge engineers. This is achieved by using a novel form of KB in which the knowledge is fragmented into separate concepts associated with design solutions. The system also includes a new style of user interface which provides a critiquing style of interaction with the KB only interacting with the user when it detects a possible error or a more suitable design solution. The new system has been developed using object oriented programming techniques which result in a structured and robust style of KB.     

Information frameworks for conceptual engineering design

An information modeling approach is used to gain an understanding of the information and decision content of conceptual engineering design. Information frameworks are presented that attempt to represent the key decisions made during conceptual design. Elements of the frameworks are derived from results from design theory and methodology and decision theory. Using a number of products, the frameworks are demonstrated in simulated design situations. The models provide an explicit, generic and consistent perspective for identifying the information content of conceptual designs.     

Novice errors in conceptual database design

Conceptual and logical database modelling are difficult tasks for designers, and the potential for committing and correcting errors is significant. This paper reports on two laboratory experiments that investigated the underlying causes of errors committed by novice designers engaged in conceptual database modelling tasks. These causes can be traced to combinatorial complexity of the task, biases resulting from misapplication of heuristics, and incomplete knowledge about database design. The most common error was that subjects translated their initial understanding of the application into final database structures and did not consider alternative hypotheses and solutions. The paper includes recommendations to reduce the occurrence of errors.     

Visual language and graph-based structures in conceptual design

The paper deals with using design knowledge encoded in a visual language and graph-based structures to support the conceptual phase of designing. The visual language is based on the design conceptualization and composed of design diagrams being configurations of geometric primitives. A symbolic representation of design structures in terms of objects specified by the conceptualization and relations between them is defined, and then mapped into diagrams by a given realization. Diagrams are automatically transformed into the corresponding graph-based data structures. The knowledge stored in the graph representations of diagrams is translated into first-order logic formulas which describe generated design configurations. A proposed logic-based reasoning mechanism allows the design supporting system to check the compatibility of designs with the given requirements and constraints. The approach is illustrated by examples of designing configurations of transmission truss towers.     

Creative conceptual design: Extending the scope by infused design

Many methods that support human creativity by manual or computational means have been proposed in the past. They rely on the assumption that following a certain process of reasoning might lead to generating ideas considered creative. We start by defining creativity as a capability that enables the creation of systems that are patentable. We review the state-of-the-art of creative conceptual design and organize it with a framework. Subsequently, we present a method called infused design that guarantees the generation of design solutions by transforming systems and methods from remote disciplines. In many cases, these solutions would be deemed creative. Finding these systems and their transformations is done through a process based on the underlying discrete mathematical representation. This process is partially supported by a computer tool.We describe the method of infused design and illustrate its operation through part of the results achieved until now, including designing a new active torque amplifier system. We further demonstrate its benefits through other examples. We discuss the relation of infused design with other creativity or design methods and conclude with future developments of the method.“A well-directed imagination is the source of great deeds.”Chinese proverb     

面向飞行器概念设计的动网格技术

在弹簧近似光滑法和局部网格重构法两种动网格方法的基础上,结合类型函数/形状函数方法,针对飞行器概念设计阶段方案多变、参数变化快的特点,对二元机翼随参数变化的翼型提出了相适应的动网格方法.该方法根据参数的影响,将变动的边界信息传递到网格上,网格随之迭代变化.相对于常用动网格方法,该方法具有更强的参数表现力和适应力,使得网格生成更快速.对类型函数/形状函数转换方法(CST)拟合的NACA2415翼型在不同迎角情况下的低速湍流流动进行了数值模拟.计算结果表明,该动网格技术较好地模拟出了翼型的流动特性,较准确地得出了翼型的气动力系数,对飞行器概念设计阶段的参数确定具有实用价值,显示了该动网格方法的准确性和便捷性.     

A CASE tool for conceptual database design

The paper describes a Computer Aided Software Engineering (CASE) tool to support conceptual database modelling. One popular approach for conceptual database modelling is use of the Entity-Relationship (ER) model. The paper proposes the use of an Enhanced Entity-Relationship (EER) model for conceptual database modelling. This Enhanced Entity-Relationship model extends the Entity-Relationship model by incorporating the generalization/specialization, aggregation and categorization abstractions. The CASE tool, which is based on the Enhanced Entity-Relationship model, is known as the Enhanced Entity-Relationship Diagrammer (EERD). In addition, the CASE tool supports direct visual query and update based on the EERM.     

An ontology-based support for product conceptual design

The research presented in this paper is a follow-up of our prior work involving the development of a graphical modeling tool to support designers at the conceptual design stage. To close the loop for supporting designers in generating design concepts flexibly, fast, and easily, an ontology-based approach for knowledge management that works along with the graphical modeling tool is discussed. Ontology and databases for the tool are developed to promote the systematic capture of design knowledge and efficient reuse of the design knowledge selection. In order to locate the proper information and query the data from the databases, the relationship between the ontology and databases, the data analysis process, ontology enrichment, and the ontology-based query engine are built to offer users multiple design results according to users’ requirements. A tire design example is presented to demonstrate the proposed approach. The ontology-based method described in this paper can help retrieve and save the complex relations, support the reasoning, integrate heterogeneous data resources and offer users more accurate, proper and comprehensive data.     

舰船概念设计中振动预报方法

以带有双层隔振装置的舰船模型为对象,利用MSC Nastran的有限元分析方法以及试验手段,对其隔振性能进行研究.将船体与双层隔振装置作为一个系统,建立三维有限元振动分析模型;以降低船体结构振动能量为目标,对发动机激励作用下的双层隔振装置与船体的振动特性进行分析;通过有限元分析方法和试验两方面的研究与对比,为舰船的减振降噪的初期概念设计提供快速预报方法.     

面向对象设计复杂性度量计算与分析

软件维护在软件开发过程中占有相当重要的位置,但是其成本往往是很难控制的.在对一种能够对软件维护性能进行预测的面向对象复杂性度量进行分析的基础上,结合实际情况分析了该算法集3个度量的缺点及联系.对于3个度量不够深入的地方补充了一些新观点.     

An Intelligent Tool to Support Requirements Analysis and Conceptual Design of Database Design

As an application of artificial intelligence and expert system technology to database design,this paper presents an intelligent design tool NITDT,which comprises a requirements specification language NITSL,a knowledge representation language NITKL,and an inference engine with uncertainty reasoning capability.NITDT now covers the requirements analysis and conceptual design of database design.However,it is possible to be integrated with another database design tool,NITDBA,developed also at NIT to become an integrated design tool supporting the whole process of database design.     

关于产品外型概念设计方法的研究

本文主要介绍了计算机辅助设计中实体造型常用的方法。如基于树结构、基于关键点的遗传算法、同伦映射法等,并通过实验结果进一步加深了对上述各方法的解释。     

Methodology for expert-system-based support of conceptual machine design

The cumulative requirements of design cannot be satisfied without the application of computer-based systems in the conceptual phase of design. The concept of intelligent CAD systems emerged at the beginning of the eighties. A practical implementation of an ICAD system can be based on an expert system with a specialized conceptual design methodology. Design prototypes may be generated by the systematic combination of known atomized building elements. To avoid combinatorial explosion, filtering is done on three levels. In the case of the pilot design expert system PANGEA, now being developed, the geometric modelling of prototypes is based on an extended B-rep scheme.     

Interdisciplinary communication medium for collaborative conceptual building design

Collaborative conceptual design involves intensive cross-disciplinary communication of design concepts and decisions. Difficulty in producing and expressing such information leads to extensive delays, miscommunication and confusion, which often have an impact upon the quality of the final design and the time required to achieve design concensus. Computer tools provide little support for the special needs for representation and reasoning posed by cross-disciplinary communication in collaborative conceptual building design. By building upon design theory, literature and observations for a case study of an actual building design project, we identify and devise computational strategies for addressing these needs. Our objective is to help improve the communication among design team members. Our test case focuses on the communication between architects and structural engineers. We propose a conceptual framework for interdisciplinary communication to support collaborative conceptual design and present a prototype called Interdisciplinary Communication Medium (ICM). Our conceptualization suggests that designers propose a shared form model, interpret the form model into discipline models, critique the discipline form models to derive behavior and compare it to function, and explain the results to other members of the team. We present this propose-interpret-critique-explain paradigm as a communication cycle for collaborative conceptual building design. We explore and test the conceptualization by modeling it with an experimental software prototype, ICM, that integrates graphic representations and AI reasoning about, the evolving building design. ICM provides a graphic environment as the central interface to reasoning tools to support collaborative design.