Classes of design — classes of methods — classes of tools

It is unrealistic to expect one computer-aided design tool to sufficiently support any one given design process. Yet it is necessary to define new CAD programs that give semantic support in design. To this end, the paper first differentiates classes of design and then attempts to establish relations between the defined classes and appropriate methods and computer-aided design tools. In three main sections it describes routine, innovative and creative design; top-down, bottom-up and case-based methods; and a set of corresponding design tools. The purpose of the paper is to make a contribution to the definition of domain specific aspects of CAD and to propose a mapping between processes, methods, and tools.     

三维螺旋弯管的建模

为了解决弯管在弯曲角度、直径、节数等变化时的三维弯管展平曲线的坐标位置以及函数关系问题,以实现大直径弯管的三维设计与制造的自动化、一体化,通过利用工程数学及画法解析几何的方法,分析和建立了弯管在三维状态下的展平曲线方程,同时编写了相应的MATLAB程序.实践证明使用MATLAB解决三维弯管的CAD/CAM问题,比以往解决轴线在同一平面内的弯管[1]问题在工程计算上有一定优势.     

基于虚拟企业生命周期的质量管理

阐述了虚拟企业生命周期理论，提出了基于虚拟企业全生命周期的质量环，对虚拟企业的生成期、运行期、发展期和终止期各阶段的质量管理问题进行了全过程的系统论述，认为虚拟企业的质量管理不仅是产品实现过程的质量管理，更是一个贯穿于虚拟企业生命周期的动态的系统管理过程。     

基于情感化设计的数控机床面板设计方法研究

目的使数控机床面板造型设计更加人性化,更符合用户的情感需求。方法以情感化设计相关理论为基础,选取典型机床面板样本,运用感性工学中的语意差异法和因子分析法,对产品形态要素进行分解研究。结果确定了机床面板造型的情感化影响因子,找到了机床面板的意象语义与形态设计要素之间的对应关系。结论综合运用三层次理论和感性工学方法,为其他种类的工业设备面板情感化分析提供一定的参考价值。     

文化创意产品设计过程情境建模方法研究

目的在产品设计过程中为了使文化创意更好地融入到产品中,有效地提高用户对文化产品的满意度,提出基于文化情境的产品设计过程方法。方法对文化产品设计过程情境建模方法进行分析,建立设计过程中的需求情境模型,运用图解思维、任务分析、情境构筑、语义差异法、感性工学和意象尺度等设计方法,建立文化情境转移模型,基于可拓学的方法提出优度评价方法,以推进方案群的优化设计。结论以酒瓶设计为例,对设计方法进行验证,表明该方法的有效性。     

The Theory of Critical Distances to estimate the static strength of notched samples of Al6082 loaded in combined tension and torsion. Part II: Multiaxial static assessment

This paper is concerned with a novel reformulation of the Theory of Critical Distances (TCD) suitable for estimating static strength of notched ductile materials subjected to multiaxial loading. The main feature of the method proposed and validated here is that the static assessment is performed by directly post-processing the linear-elastic stress fields in the vicinity of crack initiation sites. In more detail, our theory is proposed to be applied in the form of both the Point Method (PM) and the Line Method (LM) and it is formalised so that it can be used in conjunction with any classical equivalent stress (i.e., Von Mises’ equivalent stress, Tresca’s equivalent stress, maximum principal stress criterion, etc.). The accuracy and reliability of such an approach was checked by using the experimental results we generated by testing cylindrical samples, containing notches of different sharpness, made of Al6082 and loaded in combined tension and torsion. Observations of the failure modes in these specimens (reported in Part 1 of this two-part series of papers) informed the development of the above approach. Our method proved to be capable of estimates characterised by the usual level of accuracy shown by the TCD when used in other ambits of the structural integrity discipline, that is, of predictions falling within an error interval of about ±20%. This result is very encouraging especially in light of the fact that our simple linear-elastic approach was used to estimate static strength even when the material in the vicinity of crack initiation sites experienced multiaxial plastic deformations and the observed cracking behaviour was rather complex. Thanks to its particular features, the approach formalised in the present paper can be considered as an interesting engineering tool suitable for performing the static assessment of notched ductile materials by directly post-processing the outputs from simple linear-elastic Finite Element (FE) models.     

基于意象尺度图的重型卡车造型设计

目的以意象尺度图为依据探索重型卡车造型设计方法。方法收集并筛选出典型样本与感性词汇后,运用语义差异法获取重型卡车的感性意象评价;采用主成分分析法建立重型卡车意象尺度图,提取感性因子;最后结合阶层类别分析明确重型卡车造型设计要素。结果通过设计实践,验证了基于意象尺度图的重型卡车造型设计方法的可行性。结论运用感性工学方法对重型卡车造型展开意象研究,明确其意象尺度分布特性,以辅助重型卡车的造型设计与开发。     

基于感性工学的手电钻设计

目的以感性工学的基本理论和方法为指导,完成手电钻的形态设计。方法应用层次分析法确定手电钻感性词汇;应用语意区分法建立语意区分量表;应用形态分析法将手电钻的形态设计要素进行分解;应用排队评价法完成方案的筛选。结果通过感性分析、感性工学的实现、感性评价实现了手电钻的形态设计。结论以感性工学为指导,有效地将产品形态中的感性与理性结合起来,可以让产品形态设计的过程更为科学化和系统化。     

Automated Design and Parametrization of Mechanical Part Geometry

Variational methods for evaluating the design of mechanisms were first introduced by this group in the form of mathematical formulations generally applicable to open- and closed-loop mechanisms. This method is extended here, and demonstrated on the design of mechanical parts in the context of automatic parametrization of the geometry. The formulation is based on the development of constraint equations that govern the relationships between geometry in a mechanical part as dictated by a designer. Instead of the tedious method of specifying mathematical relations between any two geometries of the part, it is proposed to use the notion of kinematic relations inherent in the formulation relating the connectivity between joints and links. Cut-joint constraints are introduced, kinematic joints in the formulation are combined, their variations evaluated, and a Jacobian is determined. Constraint violations are then compensated to compute an assembled mechanism, hence redesigning the part. It is shown that this kinematically-driven formulation is broadly applicable to 2D and 3D models. The method and algorithm are illustrated through a number of examples.     

Grammatical approaches to engineering design,part II: Melding configuration and parametric design using attribute grammars

Parametric design tools are applicable in engineering design when the configuration is known a priori. Grammatical approaches to design, on the other hand, are useful for considering a range of configurations but do not accommodate the consideration of engineering parameters and design requirements. We discussattribute grammars, which were developed for the semantic analysis of computer languages, and show how engineering design can be facilitated by modest extensions of the attribute grammar formalism. We demonstrate with examples how a component-based design artifact language can be augmented with engineering parameters and how such a language can be parsed to evaluate conformance with design requirements. We also demonstrate how grammatical attributes can be used to represent design requirements and can direct the generation of design alternatives.     

基于感性工学的汽车驾驶空间内饰优化设计

目的 基于感性工学相关理论,以青年群体为对象,研究汽车驾驶空间内饰的优化设计。方法 以汽车驾驶空间内饰设计现状分析与问卷调研为基础,结合专家论证,完成样本筛选。基于感性意象词汇收集与筛选,采用语义差异分析法和Likert心理量表分析法,从造型、色彩、材质、功能和体验5个方面进行产品感性意象分析。结合MSA多层次方法推导并提取关键设计要素,推导得出汽车驾驶空间内饰设计方案并进行结果验证。结论 整个设计过程较为深入地探讨了设计需求与设计形态之间的关联。基于感性工学理论,研究得出了有利于特定群体汽车驾驶空间内饰优化设计的思路和方法。研究结果有望为感性工学理论在汽车内饰设计中的应用研究提供新思路,为青年群体汽车驾驶空间内饰设计提供新方法。     

我国软件与系统工程标准化研究综述

软件工程将工程化的思想贯穿到软件的分析、设计、实现和维护的生存周期全过程,涵盖完成一个软件产品所必备的思想、理论、方法、技术、工具和环境.软件工程标准化通过制定、贯彻并监督实施标准,规范软件工程过程和方法,提高软件产品质量和工作效率,对软件行业的发展起着举足轻重的作用.本文对软件工程及标准化情况进行综述,并对软件工程重点领域的发展和标准化趋势进行分析总结.首先,本文总结软件工程的发展历程,对软件工程发展各阶段的技术和标准化重点进行分析,然后通过对国际标准和我国标准进行对比,剖析出我国软件工程及软件工程标准化情况,最后归纳总结我国软件工程标准化现存的问题和下一步研究工作的重点.     

从造型语义看川酒酒瓶设计

目的针对古代酒具和川酒酒瓶造型案例进行设计分析,挖掘造型中所蕴涵的语义情境和情感态度等关系。方法对古代酒具及川酒酒瓶造型中的语义表现形式进行梳理分析,提出酒瓶造型设计新趋势,即以生态景观"竹"为对象,对川酒酒瓶进行探索性的创新设计。结论酒瓶造型语义是多种元素的综合体现,设计师应从理性思维出发,正确处理好造型语义与精神文化内涵的共生关系,达到建设川酒品牌的目的。     

Cradle-to-grave simulation-based design incorporating multiscale microstructure-property modeling: Reinvigorating design with science

We propose a new paradigm for design that incorporates scientifically oriented research directly and feasibly into engineering design practice. The goal is to use this simulation-based tool earlier in design to achieve more optimized components and systems. The method to accomplish this bridge of science and engineering is by using thermodynamically constrained internal state variables that are physically based upon microstructure-property relations. When the microstructure-property relations are included in the internal state variable rate equations, history effects can be captured. Hence, the cradle-to-grave notion arises. The method to help determine the appropriate microstructure-property relations for the internal state variables is through a multiscale modeling methodology which includes experimentation. As such, scientifically oriented research occurs in the multiscale methodology, and the engineering design practice employs the cradle-to-grave internal state variable model. An example of the multiscale methodology is presented in terms of a cast A356 aluminum alloy used in automotive design, and an example of the cradle-to-grave simulation based design is presented in terms of a stamped product used in a crash scenario.     

Analysis of powder steel material,laser sintering technology and machining on surface parameters and fatigue

The technology of selective laser melting (SLM) is booming in all engineering applications today and tends to expand production of statically and dynamically loaded parts, not only for the prototypes but also for direct metal end–use parts. However, apart from design and type of loading, there still is a number of real material and technological parameters that contribute to the final quality of the produced parts and affect or improve the surface integrity and life of the parts. This paper expands the results and conclusions made in some previous works and presents all data from the tests expressed in their technological relations. The main conclusion is that a suitable machining process did not affect the surface integrity and fatigue of the tested samples, and the key role in assessments were the material structure, its homogeneity and defects.     

Effectivity date analysis and scheduling

The impact of design on logistics cannot be ignored, and design for logistics is a new concept similar to design for manufacturing or design for assembly. Engineering change is one of the scenarios that would require logistics support. Change control of a product data management (PDM) system is one of the major approaches for handling engineering changes today. According to principles of configuration management, during the change control workflow, there are three different dates: release date, effective date, and effectivity date utilised for controlling and managing change planning and scheduling. Effective date is the exact date that a released change takes effect to the shop floor workshop. Effectivity date is the expected date that decision makers plan for the change to take effect. In normal situations, multiple disciplines, such as design and development, purchasing, shop floor workshop, quality control, and so on, are involved in making a change decision on when a change is to become effective. In this paper, a linear programming effectivity decision model is proposed to concurrently support changes of design scheduling, and production planning and scheduling when an engineering change occurs. The proposed model succeeded in solving an integration problem of design scheduling, production planning and shop floor scheduling.     

Event oriented system analysis

This article presents an attempt towards a probabilistic event oriented system analysis in engineering. Engineering systems are represented as either complete or incomplete systems of events and as compounds of various subsystems of events. The event oriented system analysis investigates important subsystems in engineering systems, such as operational modes and failure modes and their interrelations. The analysis is also applicable to engineering systems with various relations among the sets of events, such as mutually exclusive and inclusive sets. Further, the systems and subsystems are subjected to probability and uncertainty analysis. The system uncertainty analysis is based on entropy. General relations among the probability, uncertainty of the system and uncertainties of the subsystems are derived by using information theory. Specific mathematical aspects and available methods in the uncertainty modelling of systems and subsystems are summarised. Numerical examples confirm the relevance of the event oriented system analysis and indicate potential improvements in system design.     

Model server enabled management of collaborative changes in building information models

The issues and challenges involved in controlling the collaborative changes in a Building Information Modeling (BIM) data repository, in a multi-model collaboration environment, are discussed. It is suggested that managing iterative changes in BIMs is a database problem, exacerbated by the long transaction times needed to support collaborative design progression. This is yet to be resolved in the construction industry and better solutions are needed to support the underlying workflows and computing operations for seamless collaboration on BIMs. With this in mind, this paper proposes the use of the structural and semantic characteristics of BIM objects as a mechanism for tracking changes across co-developed solutions. The creation of object signatures, using hash codes derived from their characteristics, provides a potential mechanism for object comparison and effective change recognition and management.