Recent developments in computer-aided design and engineering

Developments in CAD and CAE are described, with particular reference to the area of solid modelling. This paper also outlines the efforts and successes (or otherwise) of some of the leading CAD companies. The need for standards and the problems inherent in their development are discussed. Finally, future trends in CAD are anticipated.     

Algorithms for a class of computer-aided design problems: A review

This paper reviews some recent results on algorithms for a class of computer aided design problems arising in control, circuit theory and steel structure design.     

A computer-aided design system for framed-mould in autoclave processing

The general computer-aided design (CAD) software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the mould design process, in addition to the material and geometry of the part. A framed-mould computer-aided design system (FMCAD) used in the autoclave moulding process is proposed in this paper. A function model of the software is presented, in which influence factors such as part structure, mould structure, and process parameters are considered; a design model of the software is established using object oriented (0-0) technology to integrate the stiffness calculation, temperature field calculation, and deformation field calculation of mould in the design, and in the design model, a hybrid model of mould based on calculation feature and form feature is presented to support those calculations. A prototype system is developed, in which a mould design process wizard is built to integrate the input information, calculation, analysis, data storage, display, and design results of mould design. Finally, three design examples are used to verify the prototype.     

A lower cost graphics system for VLSI design,design rule checking and pattern generation

Increasing interest by traditional systems houses in the design of custom and semi-custom integrated circuits (LSI and VLSI) provided the impetus for the development of a lower cost interactive graphics systems (IGS) for VLSI design, design verification, and the efficient generation of optical pattern generation and electron beam control files.While extremely attractive, but expensive, IGS units are available from such manufactures as Applicon and Calma for use in very large design groups, it was felt that a lower cost system incorporating the latest in design aids was needed for smaller or geographically dispersed design operations. This paper describes the implementation of one such system, and examines the various implementation options which must be examined by any group which might wish to build or acquire such a capability.     

并流喷雾干燥塔的计算机辅助设计研究

喷雾干燥广泛应用于众多工业品的生产。图解积分法是目前求喷雾干燥塔塔径和塔高常用的方法,但是图解积分法计算过程繁琐,误差大且无法编程计算。因此将喷雾干燥塔中雾滴运动的阻力系数与雷诺数之间的关系用误差极小的多项式取代图解积分法中使用的误差较大的Allen公式,并给出了喷雾干燥塔塔径和塔高的积分式,利用四阶复化高斯～勒让德数值积分法计算喷雾干燥塔塔径和塔高,有效地提高了设计精度,利用可视化语言Visual Basic6．0开发计算机辅助设计软件。算例表明：计算机辅助设计方便、结果精确,为进一步实现并流喷雾干燥塔的优化设计提供了一个有效的设计方法与手段。同时建立以年总费用为目标函数的并流喷雾干燥塔经济评价模型,对并流喷雾干燥塔的设计参数如空气进出口温度、空气进口湿度等参数进行经济评价与分析,探讨其对并流喷雾干燥塔运行费用与年总投资的影响,对实现并流喷雾干燥塔的优化设计,降低能耗,节省投资具有一定的参考价值。     

Automata theory,computer-aided design,and some problems of informatics

The main stages of formation and development of automata theory and its applications to computer-aided design of computing systems are considered. Some open problems of modern theoretical cybernetics are discussed. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 3–7, September–October 2007.     

Structuration theory and new technology: analysing organizationally situated computer-aided design (CAD)

It is becoming generally established that modern research and writings need to acknowledge the organizational context that surrounds the use of a technology (see Rachel & Woolgar, 1995; Westrup, 1996). However, previous efforts have been criticized for their failure to accumulate consistent research findings or develop coherent theoretical frameworks (Markus & Robey, 1988). Part of the problem is that a wide diversity of perspectives is adopted by organizational researchers, and fundamental issues behind these perspectives have yet to be properly examined and resolved (see Burrell & Morgan, 1979); this paper adopts the perspective that some resolution of these issues is possible, or at least should be sought. One approach is to adopt the theoretical framework, built on Giddens' structuration theory (Giddens, 1990), as presented by Orlikowski and Robey (1991), and to use it to analyse a new technology case, that of computer-aided design/draughting.     

隧道照明系统辅助设计与优化分析软件研发

为提高公路隧道照明系统设计的效率和节能水平,基于IESNA LM-62标准的灯具配光数据文件,并以逐点法为照度和亮度计算方法,在VB.net平台中开发面向公路隧道的照明系统辅助设计与优化分析软件.软件包括的功能有:基于车流量、洞外亮度和运行车速的三因素动态调光、各照明区段的长度与亮度分析、灯具回路设计与模式搜索法安装参...     

可分幅式柱状图的参数化计算机辅助设计

钻孔柱状图是工程勘察工作中的一类基础图件.从钻孔柱状图机助编绘的现状和特点出发,为了进一步提高系统的功能适应性,就其图件模型、图形参数分解和生成流程展开了分析和研究,实现了新型可分幅式钻孔柱状图的参数化机助设计与生成.实践证明,钻孔柱状图的计算机辅助设计可以达到很高的自动化程度,并且由于采用参数化方式,生成过程灵活,数字化成果图件能够满足实际工作的要求,在地质勘查信息化工作中具有很好的应用前景.     

Corporate videotex systems and cost effectiveness

The applications for corporate videotex systems are growing at a truly rapid rate. This paper looks at the reasons behind this growth, examines how systems are being built and details the type of cost benefits derived by some existing users of videotex technology.     

Tolerances in computer-aided geometric design

In the design of discrete part shapes, the specification of tolerance constraints can have major consequences for product quality and cost. Traditional methods for tolerance analysis and synthesis are timeconsuming, and have limited applicability. This paper presents the results of research into the use of solid modeling technology for the automated solution of tolerancing problems. A linear programming method is presented for the solution of tolerance analysis problems on a worst-case basis. A Monte Carlo method is presented for both worst-case and statistical tolerance analysis. Both methods automatically derive all necessary geometric relationships from a solid model of the assembly. Example problems are solved using the experimental GEOTOL geometric design system.     

Expressing standards for computer-aided building design

This article discusses a set of techniques for expressing and organizing the contents of building design standards, and suggests that application of these techniques, in conjunction with a restructuring of data flow strategies within CABD (computer-aided building design) software systems, are needed to reduce the effort and cost required to maintain CABD systems applicable and current. The article stresses application of these techniques to analysing the clarity, consistency, and completeness of existing building design standards, and to developing new standards. The SASE (Standards Analysis, Synthesis, and Expression) software system, a convenient implementation of the techniques, is presented. The method of use of standards represented by these techniques within a CABD environment is discussed as are implications of the logical expression of standards for constructing expert systems for the building process.     

Ten challenges in computer-aided design

This short paper presents 10 challenging research areas in the general field of computer-aided design. The research problems come from the author's personal experience, and as such are highly subjective. All findings and opinions are those of the author and do not represent any of the institutions the author is affiliated with.     

Developing CAD techniques for preliminary architectural design

Theoretically the computer can offer the architect significant help during the preliminary design stages. To take full benefit of its capabilities it is necessary to use the computer for the design process itself. To this end, a program has been written that concentrates on ease of use so that the machine does not impede the creative process. The program works through the manipulation of design elements such as spaces and windows, not graphical ones. The result is a tool which offers improved efficiency, but is very different from current methods that use paper in preliminary design.     

Towards computer-aided configuration design for the life cycle

In modern design, life-cycle concerns such as recycling and service are receiving increased attention. The configuration design phase, where the product and component structure is established, is of particular importance when designing for the life cycle. In this paper, the foundation for a CAD system supporting configuration design for the life cycle is presented. A prototypical CAD system, called CODA (Configuration Design of Assemblies), is under development based on this foundation. A discussion on the supported product and component representation is given, followed by a portrayal of some of the capabilities to support life-cycle design. Specifically, requirements are identified for the information needed to support design for assembly, disassembly, service, recycling, and reuse. A case study involving the (re)design of a hand-held tape recorder with respect to improved disassemblability and recyclability is utilized to highlight some of the capabilities of the current system. With the new product and component representation embodied in CODA, improved support over current CAD systems is provided for configuration design and life-cycle design assessments.     

Cost-effective design for injection molding

It is commonly agreed that a large proportion of the ultimate product cost is determined at product design stage. Therefore, a cost-effective design cannot be obtained unless all cost issues are resolved at early design stage. Therefore, instead of performing cost estimation after design, research presented in this paper aims to provide on-line cost evaluation and advisory to help product designers avoid cost-ineffective design. The objective can be obtained by (1) identifying factors that might affect product cost at each product design stage, (2) developing a design for cost effectiveness methodology that accommodates the concepts of concurrent engineering, and (3) developing a computer-based design for cost effectiveness system based on the proposed methodology. In this research, we focus on injection molding product design due to the advantages of injection molding process, such as high production rates, excellent quality and accuracy of the parts, and very long mold life. This paper first reviews and characterizes the conventional molding product development process with an emphasis on the identification of cost factors. Based on the results of process characterization, a cost model is developed, which depicts the relationships between cost factors and product development activities, as well as their relationships with product geometry. According to the product life cycle activities and the cost model, a design for cost effectiveness process is proposed. The process and the cost model are then employed for the development of a computer-based product design for cost effectiveness as one of the module of an integrated design for injection molding environment.     

3D modelling and model management applied to ship design

The application of a Computervision CADCAM system in ship design and building is presented. The complexity of the design of ships meant that the Computervision software had to be adapted to the specific requirements of the ship design company, Vosper Thornycroft. The objectives, approach and method used by Vosper Thornycroft in developing the software is described, and problems experienced in applying the system are examined.     

Maintenance of integrity during concurrent access in a building design database

This paper proposes an implementation structure and the corresponding relational model for a building design database. The structure strongly supports designer—database interaction by providing extremely versatile access mechanisms and an associated concurrrency control mechanism. It is demonstrated that the relational model provides a flexibility of access not readily available in other models. The implementation structure supports designer access to database entities by location, attribute value, and combinations of both. It also supports ad hoc groupings of data. At the same time it maintains the integrity of the database against violations caused by concurrent use. Existing concurrency control methods are explored and a new level of locking for concurrency control is proposed. The module is recommended as the optimal level to which a locking mechanism be applied.