Engineering Design Processes: A Comparison of Students and Expert Practitioners

In this paper we report on an in‐depth study of engineering design processes. Specifically, we extend our previous research on engineering student design processes to compare the design behavior of students and expert engineers. Nineteen experts from a variety of engineering disciplines and industries each designed a playground in a lab setting, and gave verbal reports of their thoughts during the design task. Measures of their design processes and solution quality were compared to pre‐existing data from 26 freshmen and 24 seniors. The experts spent significantly more time on the task overall and in each stage of engineering design, including significantly more time problem scoping. The experts also gathered significantly more information covering more categories. Results support the argument that problem scoping and information gathering are major differences between advanced engineers and students, and important competencies for engineering students to develop. Timeline representations of the expert designers' processes illustrate characteristic distinctions we found and may help students gain insights into their own design processes.     

齐彭代尔设计思想对新中式家具的启示

目的 通过研究齐彭代尔的设计思想和设计方法,重新审视新中式家具中传统文化元素的感知方式和设计思考路径,探究传统文化元素在新中式家具设计中的应用策略,为新中式家具设计提供持续的创造源泉。方法 通过对齐彭代尔设计作品的梳理,结合当下新中式家具的设计现状,针对性地分析齐彭代尔的设计方法,并导入实际工程项目进行设计实践与论证。结论 新中式家具并非传统中式家具的改良产品或者次生品,而是与传统中式家具平行且独立的当代“东方（或中国）”家具成果,将传统文化引入现代的家具设计,可以带来更多的可能性,也是我国未来家具产业发展的趋势。齐彭代尔家具设计兼容并蓄,大胆破立,并且形成了系统的设计方法,值得在探索新中式家具的研发与创新中进行学习和借鉴。     

Individual styles of problem solving and their relation to representations in the design process

The goal of the empirical study presented in this paper was to investigate the influence of individual styles of problem solving on the design process. Subjects worked on an adaptive design problem, as well as on two, complex nondesign problems. In analysing the design processes, the main focus was on the marks-on-paper which are created and used by the designers. The results demonstrate that the course of the design process in general and the use of marks-on-paper in particular depend on an individual designer's style of problem solving. Implications ;for design education and design support are discussed.     

Design and other types of fixation

Design educators often comment on the difficulties that result from a premature commitment by students to a solution to a design problem. Similarly practitioners can find it difficult to move away from an idea they have developed or precedents in a field. In the psychology of problem solving this effect is called functional fixedness or fixation. It is not surprising that these effects should occur in design problem solving. However, while these types of issues have been discussed in the context of design, there has been little systematic evidence available about whether or not and under what conditions design fixation does occur. The paper reviews the results of a series of recent experiments which begin to address these issues. The results of the experiments are examined in terms of what insights they provide into the design process, what implications they have for design education and how they relate to the larger and more general area of human problem solving.     

An adjoint method for the inverse design of solidification processes with natural convection

This paper presents a finite element algorithm based on the adjoint method for the design of a certain class of solidification processes. In particular, the paper addresses the design of directional solidification processes for pure materials such that a desired freezing front heat flux and growth velocity are achieved. This is the first time that an infinite-dimensional continuum adjoint formulation is obtained and implemented for the solution of such inverse/design problems with moving boundaries and Boussinesq incompressible flow. The present design problem belongs to a category of inverse problems in which one is looking for the unknown conditions in part of the boundary, while overspecified boundary conditions are supplied in another part of the boundary (here the freezing interface). The solidification design problem is mathematically posed as a whole time-domain optimization problem. The gradient of the cost functional is calculated using the solution of an appropriately defined continuous adjoint problem. The minimization process is realized by the conjugate gradient method via the solutions of the direct, adjoint and sensitivity sub-problems. The proposed methodology is demonstrated with the solidification of an initially superheated liquid aluminum confined in a square mold. The non-uniformity in the casting product in the direction of gravity due to the existence of natural convection in the melt is emphasized. The inverse design problem is then posed as finding the appropriate spatial-temporal variations of the boundary heat flux on the vertical mold walls that can eliminate or reduce the effects of convection on the freezing interface heat fluxes and growth velocity. The numerical example demonstrates the accuracy and convergence of the adjoint formulation. Finally, open related research design problems are discussed. © 1998 John Wiley & Sons, Ltd.     

A study of convergence in decentralized design processes

The decomposition and coordination of decisions in the design of complex engineering systems is a great challenge. Companies who design these systems routinely allocate design responsibility of the various subsystems and components to different people, teams or even suppliers. The mechanisms behind this network of decentralized design decisions create difficult management and coordination issues. However, developing efficient design processes is paramount, especially with market pressures and customer expectations. Standard techniques to modeling and solving decentralized design problems typically fail to understand the underlying dynamics of the decentralized processes and therefore result in suboptimal solutions. This paper aims to model and understand the mechanisms and dynamics behind a decentralized set of decisions within a complex design process. By using concepts from the fields of mathematics and economics, including Game Theory and the Cobweb model, we model a simple decentralized design problem and provide efficient solutions. This new approach uses matrix series and linear algebra as tools to determine conditions for convergence of such decentralized design problems. The goal of this paper is to establish the first steps towards understanding the mechanisms of decentralized decision processes. This includes two major steps: studying the convergence characteristics and finding the final equilibrium solution of a decentralized problem. Illustrations of the developments are provided in the form of two decentralized design problems with different underlying behavior.     

Unexpected discoveries and S-invention of design requirements: important vehicles for a design process

Designers, during a conceptual design process, do not just synthesize solutions that satisfy initially given requirements, but also invent design issues or requirements that capture important aspects of the given problem. How do they do this? What becomes the impetus for the invention of important issues or requirements? So-called ‘unexpected discoveries', the acts of attending to visuo-spatial features in sketches which were not intended when they were drawn, are believed to contribute to it. The purpose of the present research is to verify this hypothesis. Analysing the cognitive processes of a practising architect in a design session, we found that in about a half of his entire design process there were bi-directional relations between unexpected discoveries and the invention of issues or requirements. Not only did unexpected discoveries become the driving force for the invention of issues or requirements, but also the occurrence of invention, in turn, tended to cause new unexpected discoveries. This has provided empirical evidence for two anecdotal views of designing. First, designing is a situated act; designers invent design issues or requirements in a way situated in the environment in which they design. We call inventions of this sort situated-invention (S-invention). Secondly, a design process progresses in such a way that the problem-space and the solution-space co-evolve. Further, this has brought a pedagogical implication as well as an insight about an important aspect of learning by experience in design.     

基于TRIZ及ABD的创新设计研究

应用基于类比的设计（ABD）和发明问题解决理论（TRIZ）的设计过程均要采用已往成功的设计实例,使两种过程具有相似性; 在分析ABD及TRIZ设计过程原理的基础上,提出将TRIZ解模型及相应的设计实例作为ABD的源设计,由类比设计过程确定目标设计及新设计的方法。造纸机改进设计实例说明了该方法的应用。     

流行文化对现代包装设计的影响

从波普艺术、时尚文化、动漫文化和新媒体4个方面具体考察流行文化在包装视觉设计中的应用,并得出结论:人是设计的最终对象,包装视觉传达设计工作必须充分关注和研究当代大众流行文化,用敏锐的文化触角来改造设计素质和启迪设计创意.     

GENERATING OPTIMAL CONFIGURATIONS IN STRUCTURAL DESIGN USING SIMULATED ANNEALING

This paper presents a combinatorial optimization procedure based on the simulated annealing approach for generation of optimal configuration of structural members. The work is based on altering the finite element model of structure by removing or restoring elements to minimize the material use subject to constraints on maximum stress value and maintenance of connectivity between elements. Such an optimization problem is categorized as a large-scale, non-convex and non-linear problem. Thus, the problem can have multi-minima and it is important to find the global optimum solution as opposed to a local minimization. To improve the computational efficiency, the non-linear shape optimization problem has been linearized and to account for the difference between the non-linear and the linearized values a correction factor is implemented. To illustrate the approach, several design examples are presented and the effect of the parameter of the simulated annealing on the final configuration design is examined. © 1997 by John Wiley & Sons, Ltd.     

厅堂音质设计响度评价新参量质疑

厅堂音质设计中响度是最基本的评价参量之一,目前通常采用相对强感（又称强度因子）G（dB）作为评价响度的参量。吴硕贤等人（2001）则认为这一参量不足以说明听众的真实感受,提出用乐队齐奏强音标志段（fone）的平均声压级协作为评价音乐厅内响度的新物理指标为好,亚可用Barton的简单修正公式进行估算厅内各处切的分布。从实用意义、客观测定、音质设计预估等方面,对此新评价参量作出剖析和评论,以说明其存在的问题和不可行性。     

Reliable design space and complete single-loop reliability-based design optimization

Reliability-based design optimization (RBDO) has been intensively studied due to its significance and its conceptual and mathematical complexity. This paper proposes a new method for RBDO on the basis of the concept of reliable design space (RDS), within which any design satisfies the reliability requirements. Therefore, a RBDO problem becomes a simple, deterministic optimization problem constrained by RDS rather than its deterministic feasible space. The RDS is found in this work by using the partial derivatives at the current design point as an approximation of the derivatives at its corresponding most probable point (MPP) on the limit state function. This work completely resolves the double loop in RBDO and turns RBDO into a simple optimization problem. Well-known problems from the literature are selected to illustrate the steps of the approach and for result comparison. Discussions will also be given on the limitation of the proposed method, which is shown to be a common limitation overlooked by the research community on RBDO.     

Product Robust Design and Process Robust Design: Are They the Same? (No.)

Taguchi's ideas of robust parameter design motivated the development of the dual-response approach, where both the mean and the variance of the quality response are modeled in terms of the design parameters and noise factors. These are then used to identify optimal settings that achieve the dual objective of optimizing the signal (the mean) and minimizing variation. While much research has been published recently with regard to how to solve the dual-response problem (DRP), relatively little attention has been given to the unique characteristics of process robust design, like the existence of systematic variation or intercorrelations among the process “controllable” variables. These properties indeed put process robust design in a category of its own (separate from product robust design). In this paper, we first expound these unique properties and develop a general formulation of the DRP as it applies to process robust design. We then report on an implementation to an industrial process in a high-tech corporation.     

Two-staged guillotine cut,two-dimensional bin packing optimisation with flexible bin size for steel mother plate design

This paper looks into the steel mother plate design problem. A slab, which is an intermediate work in process, is subsequently rolled into a mother plate with the specific dimensions of thickness, length, and width. The mother plate is then cut into customer order plates. As a slab is rolled into a mother plate through a series of horizontal and vertical rolling processes, different-sized mother plates can be generated from a single-slab type. This flexibility allows for the size of a mother plate to be determined according to the order plates assigned to it. Furthermore, when the order plates are cut from a mother plate, a guillotine cut is required to reduce the production cost. The steel mother plate design problem involves the placing of order plates on the mother plates in a guillotine cut pattern and determining the sizes of the mother plates with the objective of minimising the number of slabs; thus it may be considered as a two-staged guillotine cut, two-dimensional bin packing problem with flexible bin size. This paper introduces the problem, presents several mathematical models, and proposes an iterative two-phase heuristic method consisting of several algorithms to solve the problem. Computational results for the benchmark problems show the effectiveness of the proposed method.     

Mixed resolution designs as alternatives to Taguchi inner/outer array designs for robust design problems

There has been considerable debate over the contributions made by Genichi Taguchi to robust process and product design. As a result of the numerous debates, there have been many alternative approaches presented that are better suited to the robust design problem. In this paper a combined array design is presented as an alternative to a standard Taguchi design. The mixed resolution design is illustrated in an example involving control and noise variables. Two new variance properties of experimental designs are also presented. Copyright © 2000 John Wiley & Sons, Ltd.     

Continuous design transmutation method for problems in engineering analysis

Many problems in engineering analysis and design involve searching solutions of a system of equations. In most cases, because these equations are highly coupled and non‐linear and thus unlikely to yield close‐form solutions, researchers seek possible solutions using numerical techniques. In this paper, we present a ‘Continuous Design Transmutation Method’, a numerical method based on the polynomial continuation theory that has been discussed in recent works appearing in engineering literature. Our model departs from similar approaches in that its start system and homotopy are based on physical design and not pure mathematical equations. To avoid singularity on real paths, we introduce a heuristic disturbance mechanism. First, we simplify target design in order to construct a design that possesses both a similar structure and known solutions. Then, we construct a homotopy between the governing equations of the simplified design and those of the target design. The solutions of the target problem emerge as one tracks the solutions of the simplified design's governing equations as these incrementally evolve from the simplified design into the target design. Using our method, one tracks only isolated solutions of the simplified problem. All of the extraneous paths have been eliminated before the solution‐tracking procedure begins. As a result, not only can one easily interpret, in physical terms, the transmutation process, but one can also monitor the design feature changes. In this paper, we demonstrate our method as applied to two sample problems: a five‐point position‐generation problem for a planar four‐bar mechanism and a function‐generation problem for an RSSR linkage. Copyright © 2004 John Wiley & Sons, Ltd.     

A methodology for planning experiments in robust product and process design

Robust design is an important method for improving product manufacturability and life, and for increasing manufacturing process stability and yield. In 1980 Genichi Taguchi introduced his approach to using statistically planned experiments in robust product and process design to U.S. industry. Since then, the robust design problem and Taguchi's approach to solving it has received much attention from product designers, manufacturers, statisticians and quality professionals. Although most agree on the importance of the robust design problem, controversy over some of the specific methods used to solve the problem has made this an active research area. Although the answers are not all in yet, the importance of the problem has led to development of a four-step methodology for implementing robust design. The steps are (1) formulate the problem by stating objectives and then listing and classifying product or process variables, (2) plan an experiment to study these variables, (3) identify improved settings of controllable variables from the experiment's results and (4) confirm the improvement in a small follow-up experiment. This paper presents a methodology for the problem formulation and experiment planning steps. We give practical guidelines for making key decisions in these two steps, including choice of response characteristics, and specification of interactions and test levels for variables. We describe how orthogonal arrays and interaction graphs can be used to simplify the process of planning an experiment. We also compare the experiment planning strategies we are recommending to those of Taguchi and to more traditional approaches.     

Linking quality citizenship to process design: a quality management perspective

As organisations emphasise their role in society, there is a need to determine the effect of socially responsible practices on organisational processes and firm performance. Although the effect of corporate social responsibility on firm performance has been addressed from different perspectives, little is known about the influence of corporate social responsibility on organisational processes and internal operations of firms. The paper aims to make a link between corporate social responsibility, quality management practices and quality outcomes through emphasising quality citizenship as one of the practices associated with quality management. This paper provides a new perspective on the link between quality citizenship and product/process design within the quality management framework. The stakeholder theory of the firm is used to explain the formation and development of new management practices within a firm. Data were collected from managers in the petroleum industry to examine the role of quality citizenship on design and development of organisational processes. The results show that quality citizenship has a significant effect on employee involvement and an indirect effect on process design. Quality citizenship enables firms to obtain a much broader perspective on product/process design and facilitates design and development of products, services and processes that meet the needs of a broader set of customers – the stakeholders.