Data base design methodology for structural analysis and design optimization

A methodology to design data bases for finite element analysis and structural design optimization is described. The methodology considers three views of data organization-conceptual, internal, and external. Tabular and matrix forms of data are included. The relational data model is used in the data base design. Entity, relation, and attributes are considered to form a conceptual view of data. First, second, and third normal forms of data are suggested to design an internal model. Several aspects such as processing, iterative needs, multiple views of data, efficiency of storage and access time, and transitive data are considered in the methodology.     

Data base system considerations in engineering design

A general structural design procedure, including general development and maintenance steps, is outlined from a data requirements perspective. Within each phase of the design process, certain data is required for the undertaking and completion of each design step. As the various steps in the design process such as component and prototype testing and in-service experience generate new or additional data, that information should be incorporated into the data banks for use in current and future designs.     

User interfaces for structural engineering relational data base

The needs of engineers in their interaction with engineering data bases are very different from those of their counter-parts in the business world. Business data base management system interfaces typically provide only a single mode of textual communication, usually a structured query language. However, in an idealengineering data base interface, an engineer would be able to define constraints, give examples, point at parts of pictures, and (sometimes) use several modes of communication simultaneously. The paper presents an example from an engineering design application to show how a traditional query language can be enhanced to accommodate the engineering needs. The paper further describes a conceptual approach for multimodal engineering data base interface combining multipurpose graphics, an engineering query language, and other interface methodologies in an engineering workstation environment.     

Version management needs for structural engineering design

As design objects are created during the design process, it is not sufficient to represent only a single current state of each object. Instead, it will usually be necessary to represent a number of past and current states, existing parallel to each other at various design stages. This requirement has led to the development of various schemes to help manage and control multiple occurrences of a design object.In this paper versions of structural engineering design objects are defined and a scheme for organizing these versions is proposed. A design for a version manager in an object-based design system is then presented. The manager has limited capabilities but can be used as a step toward defining a more complete version management and control system.     

An object design framework for structural engineering

Object-oriented principles have introduced several useful concepts for developing complex software systems. As a result, several methodologies have been suggested for the overall design of software systems based on these concepts. Methodologies and frameworks for designing objects that are to be part of the software systems are currently lacking. This paper proposes anobject design framework andmethodology, which utilizes the object-oriented concepts, for planning, organizing and designing structural engineering design objects. Design objects in an integrated structural engineering system are complex and often related to each other in various different ways. The paper also identifies several important relationships among structural engineering design objects. These relationships serve as communication channels through wich design objects send messages to and receive responses from each other. Several examples, drawn from reinforced concrete structures, will be presented to demonstrate the object design methodology and to illustrate how the framework is effective in reducing the complexity of design objects in an integrated structural engineering system.     

The methodology for design of effective computer-integrated manufacturing systems

This paper the combines group technology and the simulation approach to the design of an effective material flow system in production processes of a discrete nature. The GT method shows how to find operational groups using a classification system, and how to design GT cells to achieve their maximal effectiveness. Dynamic modelling and simulation of the designed system are emphasized as the tools for checking the behavior of the designed structure and measuring its effectiveness. An example of an application of the suggested approach in the case of a textile machine factory is discussed.     

CAL packages for civil engineering hydraulics and structural design

The paper describes CAL packages developed for use in a degree course in civil engineering; all are used in the interactive mode through a terminal with a keyboard and visual display unit. They relate to the subjects of hydraulics and structures, although the application of CAL is being extended more widely. Common features in their development are emphasized; each is described in outline and an indication is given of ways in which they may be employed.The hydraulics packages are arranged both to explain methods of calculation and to permit rapid computation of otherwise lengthy examples. The first open channel package covers uniform flow and, so, the calculation of normal depths; the second non-uniform flow and surface profiles. The surge shaft package deals with oscillations of level in a surge shaft on a pipeline supplying a turbine to which the flow is abruptly changed.The structural design packages cover the topic of steel beams. They emphasize principles and concepts and the construction of bending moment and shear force diagrams. Moreover they are so devised as to give the student concentrated design experience enabling him rapidly to establish what section is appropriate to meet the requirements of deflection, shear and bending for given lengths, loading and grade of steel. Both rolled and welded beams are covered.All programs are written in FORTRAN IV with routines to provide for such matters as free-format input/output and data range-testing. Graphical displays are made possible by the use of a microprocessor-based graphics-option controller used in conjunction with a standard alphanuneric terminal and VDU.     

A design process model for computer integrated structural engineering

Computer integrated design systems will require an improved understanding of the engineering design process, including formalized notions of (1) the structure of the process, (2) the design tasks that need to be performed, and (3) the information required to carry out these tasks. To help formalize the design process, certain conceptual tools are needed, including an organizational model for the process. This paper outlines such a model for structural engineering design, termed theMultilevel Selection-Development model, which is based on a decomposition of design problems intoselection anddevelopment subproblems. A few basic concepts involved in the engineering design process are reviewed, and the proposed model is outlined. The application of the model to a simple example is presented, and management of the interactions between subproblems is discussed.     

Object-oriented intelligent computer-integrated design, processplanning, and inspection

The methodology for developing intelligent integrated computer-aided design and manufacturing systems based on object-oriented principles is discussed. The ways in which the application of these principles affects the nature of these systems are reviewed. The implementation of an automated, intelligent, and flexible computer-integrated-manufacturing (CIM) system prototype using an object-oriented programming environment (Smalltalk-80, Version 4.0) is detailed. A CIM system includes CAD, a process planner, and an inspection planner. Each of these components is discussed individually     

Data base design constrained by traffic load estimates

This paper discusses a mathematical model for finding an effective design of a logical data base. It is argued that a logical data base should not only integrate multiple users' views of information. It should also reflect the data base activity of each individual application and be based on performance tradeoffs among the different applications. Our model shows how this activity can be mapped into activity within the global information structure which describes the integrated view of the information. This is an aid for subsequent logical record definition and schema design.

The model is based on knowledge of a large number of input parameters, some of which have greater impact on the final data base solution than others. Sensitivity analysis of the system's behaviour with respect to changes in parameters help focus on the most critical parameters. This reduces the efforts devoted to quantification of parameters, so that default values or very rough estimates are sufficient for the least critical parameters.     

Implementation of knowledge-based engineering methodology in ship structural design

The work presents a knowledge-based engineering (KBE) methodology for ship hull structural member design. In the ship design process, many design tasks need the expertise or design experiences to support them. However, the ship design procedure is a complicated process with many labor-intensive activities. Therefore it is necessary to integrate intelligent design process into ship design. An application developed in a KBE system takes design requirements, applies the knowledge stored in the knowledge base and generates a new design automatically. Knowledge-based engineering methods for ship design are put forward, which combine with the theory of intelligent design. A ship deck design case illustrates the feasibility of the proposed approach. The KBE technology provides appropriate suggestions and support, integrates the information, to avoid conflict and errors. Besides, it also achieves knowledge reuse and accumulation, provides reliable technical support for ship design quality, significantly reduces the design cycle, and promotes working efficiency.     

Data base design with the constrained multiple attribute tree

A Multiple Attribute Tree [10] is a directory type access mechanism to retrieve data base records that are indexed by several attributes. Here we deal with the construction of an optimal MAT where the number of buckets available for accommodating the data base is constrained. This data structure is called a Constrained Multiple Attribute Tree (CMAT). We present an algorithm for constructing an optimal CMAT from a given MAT for data bases in which the values assigned to attributes of a record are independent.     

Group technology applications for computer-integrated manufacturing

Traditionally, group technology has dealt primarily with batch-type manufacturing which is engaged with small lot sizes and a variety of products. Recently, however, due to the development and implementation of computer- integrated manufacturing, group technology has been recognized as an essential element of the foundation for the successful development and implementation of computer-integrated manufacturing through the application of the part-family concept and also a common database for CAD/CAM integration. The optimum design and effective operation of a fully automated manufacturing cell system and/ or factory systems for factories of the future require a careful analysis of all the requirements which the system must satisfy under a group technology environment.     

An experimental design approach using TOPSIS method for the selection of computer-integrated manufacturing technologies

The selection of Computer-Integrated Manufacturing (CIM) technologies becomes more complex as the decision makers in the manufacturing organization have to assess a wide range of alternatives based on a set of attributes. Although, a lot of Multi-Attribute Decision-Making (MADM) methods are available to deal with selection applications, this paper aims to explore the applicability of an integrated TOPSIS and DoE method to solve different CIM selection problems in real-time industrial applications. Four CIM selection problems, which include selection of (a) an industrial robot, (b) a rapid prototyping process, (c) a CNC machine tool and (d) plant layout design, are considered in this paper. TOPSIS method and Design of Experiment (DoE) are used together to identify critical selection attributes and their interactions of all these cases by fitting a polynomial to the experimental data in a multiple linear regression analysis. This mathematical model development process involves TOPSIS experiments with the model. The regression meta-model greatly reduced the cost, time and amount of the calculation step in application the TOPSIS model. Application results were validated and shown that they provide good approximations to four decision making problem's results in the literature.     

Data Mining based mutation function for engineering problems with mixed continuous-discrete design variables

Genetic algorithms are well established for solving engineering optimization problems having both continuous and discrete design variables. In this paper, a mutation function for discrete design variables based on Data Mining is introduced. The M5P Data Mining algorithm is used to build rules for the prediction of the optimization objectives with respect to the discrete design variables. The most promising combinations of discrete design variables are then selected in the mutation function of the genetic algorithm GAME to create children. This approach results in faster convergence and better results for both single and multi-objective problems when compared with a standard mutation scheme of discrete design variables. The optimization of a vehicle space frame showed that a mutation probability between 40% and 60% for the discrete design variables results in the fastest convergence. A multi-objective aerospace conceptual design example showed a substantial improvement in the number of pareto-optimal solutions found after 100 generations.     

化工基础课堂教学及实验教学数据处理的窗体化设计

为解决化工基础课堂教学和实验教学中的数据处理难题,可利用Visual Basic6.0语言编写出处理其数据的程序。通过简单的窗体操作和程序运行,即可计算有关过程及作图,打印出所需的结果和图表。本程序可在Win9X操作平台下独立运行,操作简便、直观、图像清晰、误差小。