Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

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The introduction of concurrent engineering has led to a need to perform product development tasks with reduced information detail. Decisions taken during the early design stages will have the greatest influence on the cost of manufacture. The manufacturing requirements for alternative design options should therefore be considered at this time. Existing tools for product manufacture assessment are either too detailed, requiring the results of detailed design information, or too abstract, unable to consider small changes in design configuration. There is a need for an intermediate level of assessment which will make use of additional design detail where available, whilst allowing assessment of early designs. This thesis develops the concept of aggregate process planning as a methodology for supporting concurrent engineering. A methodology for performing aggregate process planning of early product designs is presented. Process and resources alternatives are identified for each feature of the component and production plans are generated from these options. Alternative production plans are assessed in terms of cost, quality and production time. A computer based system (CESS, Concurrent Engineering Support System) has been developed to implement the proposed methodology. The system employs object oriented modelling techniques to represent designs, manufacturing resources and process planning knowledge. A product model suitable for the representation of component designs at varying levels of detail is presented. An aggregate process planning functionality has been developed to allow the generation of sets of alternative plans for a component in a given factory. Manufacturing cost is calculated from the cost of processing, set-ups, transport, material and quality. Processing times are calculated using process specific methods which are based on standard cutting data. Process quality cost is estimated from a statistical analysis of historical SPC data stored for similar operations performed in the factory, where available. The aggregate process planning functionality has been tested with example component designs drawn from industry.

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In traditional aircraft wing structural design, the emphasis has been on pursuing the minimum weight or improved performance. The manufacturing complexity or cost assessments are rarely considered because it is usually assumed that the minimum weight design is also the minimum cost design. However, experience from industry has shown that this is not necessarily the case. It has been realised that in the cases where no manufacturing constraints are imposed, the extra machining cost can erode the advantages of the reduced weight. As manufacturing cost includes material cost and machining cost, whilst reducing weight can reduce the material cost, if the manufacturing complexity increases greatly as a result the overall cost may not go down. Indeed, if the manufacturing complexity is not checked, the machining cost could increase by more than the amount by which the material cost reduces. To enable the structural manufacturing complexity to be controlled, manufacturing constraints are established in this thesis and integrated into the optimisation of the aircraft wing structural design. As far as the manufacturing complexity is concerned, attention has been paid to both 3-axis and 5-axis machining. The final designs of optimisations with manufacturing constraints prove the efficiency of these constraints in guiding the design in the manufacturing-feasible direction.

The research reported in this thesis had two aims. To investigate how the variability and complexity of the mobile context of use should be addressed when capturing user needs for mobile products and to explore the role of indirect methods of data capture as tools for eliciting user needs in a form appropriate for informing the scenario based design of mobile products during the. earliest stages of product development. This research presents a novel scenario-based approach to eliciting and representing user needs in a form suitable for informing the earliest exploratory stages of mobile product design. Within this approach scenarios are used to provide snapshots of actual or envisaged product use that can be used to find a starting point for design when there is no clearly defined focus for innovation. Scenarios are organized into sets using scenario tables to structure consideration of key variables within the mobile context of use. These key variables are identified as: mobility, emotion, social relationship and communication purpose. Three user studies were conducted using UK undergraduate students as the study population. Study One explored use of schematic representations ('maps') of each participant's social communications and mobility as tools for eliciting user needs, both in relation to existing mobile product use and in relation to projected use of future mobile product concepts. Study Two used a diary study method to explore existing mobile communications use. Ways of structuring consideration of the mobile context of use were explored and the effectiveness of the diary as a tool for eliciting user needs and for scenario generation was assessed. Study Three extended the diary study approach to include consideration ofthe emotional context of product use and to include pictorial feedback of diary entries to study participants. These personal representations of product use were used to further explore user needs and to prompt participants to generate narratives describing motivations for product use suitable for presentation in scenario form.

Three-dimensional appearance models represent an essential outcome of industrial design practice, facilitating the origination, evaluation and specification of exterior form. As manufacturers face increasing pressure to reduce time scales for new product development, the production of such models using conventional fabrication techniques must be appraised. As a means of economically translating digital geometry into one-off components, rapid prototyping has the potential to contribute towards a reduction in lead times for the production of appearance models. The objective of this research is to propose a methodological approach for the effective integration of rapid prototyping within industrial design practice. The field and practice of industrial design is defined, the technology of rapid prototyping discussed, and their integration proposed through a draft computer-aided industrial design/rapid prototyping (CAID/RP) methodological approach. This is exposed to practitioner feedback, modified, and employed as a revised CAID/RP methodological approach during the industrial design of a nylon line trimmer. The product outcome is used to compare and contrast the production of an appearance model via rapid prototyping, an appearance prototype via rapid prototyping, and an appearance model via conventional fabrication techniques. Two issues arise from the use of the revised CAID/RP methodological approach: the production of stl files and the lack of physical interaction with product form. In addition, the emergence of rapid prototype sketch modelling systems following the line trimmer case study provides an opportunity for further enhancement. A strategy for the resolution of these issues is proposed, and their effectiveness evaluated through additional case studies. The resulting CAID/RP methodological approach is subject to validation through practitioner interviews and a normalised rating/weighting method. The positive feedback acknowledges the significance of the CAID/RP methodological approach through a reduction in product development lead times and enhancement of professional practice. The project makes a contribution to new knowledge and understanding in the area of professional practice through the definition and validation of operational paradigmatic change.

Each year in the UK (United Kingdom) hundreds of millions of consumer products are sold, leading to many millions of tonnes of waste being buried or burned annually. While there are many large businesses that produce consumer products, in the UK small product design consultancies (SDCs) make up approximately half of all employed designers. This thesis outlines an investigation into the absence of an EcoDesign agenda in product design briefs and how this might be changed in the future. In order to best establish the theoretical basis of the research, a comprehensive literature review was conducted into the practice of product designers, their relationship to society and the wider environment. In addition, existing tools and resources purporting to support product designers, with the implementation of EcoDesign projects, were analysed to understand the challenges associated with their design. Following this review, and the development of relevant research questions, a series of semi-structured in-depth interviews were conducted to understand SDCs better, how these organisations conduct their business, and how familiar they are with EcoDesign. A series of semi-structured in-depth interviews were conducted with 26 participants from 22 different consultancies. As a result of these interviews, a greater understanding of the barriers and drivers SDCs face in the practice of EcoDesign was established. This led to the creation of d.eco a web-based resource, to facilitate the implementation of EcoDesign principles in SDCs. This resource was evaluated in the final stage of the research. The majority of product designers had an awareness of EcoDesign and considered that they would be able to use their skills to find the information necessary to create products with a reduced environmental footprint. A significant barrier was that EcoDesign principles could only be legitimately applied when the design brief required their use. However, briefs are not created solely by clients; they were found to be much more collaborative, thus offering designers an opportunity to influence their own briefs. So, the role of an EcoDesign resource is less about assisting the design process, like most existing tools, and more to do with the providing designers with a wellspring of inspiration. However, the resource stimulates more than just creativity. It also provides peer recommended examples of existing EcoDesign products, materials and processes, facilitating the long-term absorption of relevant information. By presenting relevant material, in an appropriate way, designers can be more confident when including EcoDesign criteria and associated principles within their briefs.

Consideration of sustainability in product and industrial design courses is becoming more common and relevant within higher education in the UK. However little is known about how widespread the teaching is and what is actually understood as sustainable design with discrepancies in the definitions used in different institutions. Literature highlights that many universities now engage with the tangible environmental aspects of sustainable design, whilst the intangible social aspects are left unaddressed. This thesis explores methods for encouraging and enabling students to address the social aspects within sustainable product design (SPD) education. The first research stage presents the results of a nationwide survey, which investigated how widely SPD is taught, which social aspects are addressed, how SPD is taught and assessed and the attitudes and awareness of it amongst academics. The second research stage presents further research into best practice in SPD through detailed interviews with leading academics in the field. A third research stage built upon the findings from both these studies, and sought to address a perceived weakness in SPD education; the lack of understanding and consideration of the social aspects in sustainable product design in teaching and project outcomes. Three Rethinking Design workshops were developed and tested at five universities in the UK and Ireland. These workshops were designed to introduce students to the wider social aspects of SPD, through the use of audio visual group based workshops. The design of the workshops enabled a learning environment where a deep understanding of the social aspects of Sustainable Product Design could be developed through; group work, discussion and critical reflection, which led to students exploring design thinking responses, suggesting that deep learning, had occurred.

This research evaluates the problems that design engineers face when trying to include environmental issues in product design without jeopardizing other design issues. A thorough review of current literature, tools and methodologies on the topic is given whilst their gaps and shortcomings are revealed and the need for a new methodology is formulated. This sets the starting point for the research and the development carried out during this research. A methodology is proposed in this thesis that helps manufacturers of complex products apply the Eco-Design principle and the whole life cycle approach without compromising the economic performance of their products. On one hand the primary objective outlined for the methodology is to include three different issues in product design: economic impact, environmental impact and functional issues whilst avoiding a trade-off. On the other hand, since the methodology is applicable to complex products, the secondary objective is to align and integrate two separate issues: alignment of the design process progress and the product hierarchy. In order to achieve those objectives existing design tools, such as the TRIZ (Theory of Inventive Problem Solving) matrix and the DfX (Design for X) method, are integrated. Furthermore a computer support tool in the form of a user interface is developed that is based on the theoretical framework of the methodology. This user interface allows for a quick analysis of a product and the production of design suggestions in order to enhance the product characteristics. The validation of the research is presented through examples and the application of case studies of different products. This case study approach helps to develop and apply findings during the methodology development and validate the functionality and flexibility of the proposed methodology. Areas of future work which can help increase the knowledge base, scope and applicability of the work carried out are identified.