Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 26-27). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 42-44). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The focus of this thesis is on the development of a conceptual design evaluation model that can be used in engineering design and can be implemented as a computer tool. A prerequisite to achieve this objective is a proper understanding of the initial phases of the design process, using an adequate framework. Hence, a brief examination of Theory of Technical Systems associated to a comprehensive study of the conceptual design stage, based on academic design methodologies and a survey amongst British industries, is presented. Additionally, evaluation issues at the early phases of design and a number of approaches for evaluating alternative solutions are investigated and relevant characteristics to be included in a prospective conceptual design evaluation model are compiled. A novel evaluation model based on function metrics has been proposed. The approach provides an intermediate evaluation, indicating which solutions have the potential to progress further in the design process The core of the model is the composition of evaluation matrices and computation of partial indices, which will originate an overall index used to classify the alternatives. The model assumes the existence of an explicit function structure on which the development of the organ/component structure is going to be based. A unique feature of this model is that it does not depend on designers' preferences or judgement in assigning values. From the formalised solution the designer has to identify which organ/component implements which function. An initial prototype of a computer tool (LiberSolutio), which embodies the above model, is presented. In addition to being an evaluation system, LiberSolutio can record the design history of the set of solutions generated for a particular functional decomposition/ structure. A preliminary evaluation of the model and computer system is also presented with conclusions drawn from the results obtained.

Product success is a major goal of designing and design research. Designing involves developing systems. A system interacts with its environment to satisfy its requirements. Therefore, designing should involve developing the concept of both the system and its surrounding. Depending on how the concept of the system changes will impinge on the concept of the environment, and vice-versa; design must co-evolve the concepts of both the system and its environment to adapt them to each other. A comprehensive review of literature on designing to explore the use of system-environment view in designing revealed that while the concept of systems is used by many design models, implicitly or explicitly, the concept of environment is rarely used as an evolvable construct in designing. Activities, outcomes, requirement-solution and system-environment views play a significant role in product success. Thus, it is important to explicitly address these views in designing. Further, integration of these views is important for explaining various complex characteristics of designing such as requirement-solution co-evolution and system-environment co-evolution. Integration of views is important also for mapping the steps in design models using these views, so as to be able to characterize design models, or benchmark one design model against another. Literature has been reviewed to identify the constructs in these views that are essential for representing the design process. Srinivasan and Chakrabarti [2010] had earlier developed a model of designing by integrating three of these views: activities, outcomes, and requirement-solution. However, this model did not incorporate the system-environment view. In this thesis, a system-environment view is developed, with both the system and environment as explicit and evolvable constructs in designing. The thesis then proposed an extended, integrated model of designing which combines the constructs of the identified views of activities, outcomes, requirement-solution and system-environment. The proposed model is empirically validated using protocols from six design sessions; the sesessions had been undertaken well before the proposed model was developed.Validation involved checking whether or not instances of all the constructs in the model are naturally present in these design sessions, and whether or not every event in these design sessions could be described using the constructs of the proposed model. Further, the explanatory power of the proposed model is illustrated by explaining how system-environment co-evolution and requirement-solution co-evolution occur during the design sessions captured in the protocols. Also, a standard prescriptive approach to designing –Pahl and Beitz approach – is used to demonstrate how a design model can be mapped using the constructs of the proposed model–the first step to characterizing or benchmarking design models.

The goal when applying robust engineering design methods is to improve a system's quality by reducing its sensitivity to uncertainty that has influence on the performance of the product. In the Robust Concept Exploration Method (RCEM) this approach is facilitated with additionally giving the designer the possibility to search for a compromise between the desired performance and a satisfying robustness. The current version of the RCEM, however, has some limitations that render it inapplicable for nonlinear design problems. These limitations, which are demonstrated in this thesis, are mainly connected to the application of global response surfaces and the Taylor series for variance estimations. In order to analyze the limitation of the robustness estimation, several alternative methods are developed, assessed and introduced to a modified RCEM. The developed Multiple Point Method is based on the Sensitivity Index (SI) and improves the variance estimation in RCEM significantly, especially for nonlinear problems. This approach is applicable to design problems, for which the performance functions are known explicitly. For problems that require simulations for the performance estimation, the simulation-based RCEM is developed by introducing the Probabilistic Collocation Method (PCM) to robust concept exploration. The PCM is a surrogate model approach, which generates local response models around the points of interests with a minimum number of simulation runs. Those models are utilized in the modified-RCEM for the uncertainty analysis of the system's performance. The proposed methods are tested with two examples each. The modified RCEM is validated with an artificial design problem as well as the design of a robust pressure vessel. The simulation-based RCEM is validated using the same artificial design problem and the design of a robust multifunctional Linear Cellular Alloy (LCA) heat exchanger for lightweight applications such as mobile computing. The structure of the theoretical and empirical validation of the methods follows the validation square.

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The usual method of designing a solution for a problem, which applies general principles to a specific situation, tends to overlook the unique features of each situation and so must inevitably efface the very structure of what it means to create, and so resolve diversity and plurality into blank uniformity. This is grave problem which a renewed attention to the individuality of things might help resolve. This project considers the criticism of several thinkers (including John Duns Scotus, Martin Heidegger, Theodor Adorno, and J.C. Jones) on the schema of general and particular that undergirds the engineering design method. It then seeks to open up further the suggestions these thinkers have for a new approach to the design method not enthralled to an understanding of general categories, but grounded in a contemplation of the individual.

There are as many perspectives in designing as there have been instances in which it has occured. In each instance, constraints will have invariably arisen in various forms, to the extent that designing and constraints are considered to be an inherently natural pairing. In addition, they are both affected by the challenges of complexity, amongst many others, which is especially compounded by an increasingly significant shift towards interdisciplinary methods and means of working. This has been in response to the influences and implications with regards to the integrated elements of sustainability and sustainable development. To this effect, the body of research effort presented in this thesis searches for a simpler perspective towards designing, to which constraint-based thinking can be applied. It explores the implications of interdisciplinarity in the context of sustainability and sustainable development. It also considers an example of design-based process within the built environment that is inclusive of multiple disciplines and therefore not only interdisciplinary, but also affected by complexity. In response to these instances of complex interdisciplinary designing, this thesis contributes an exploration of constraint-based thinking and the consideration of an approach which uses design objectives as optimisation constraints, from which a methodology has been created. Furthermore, this thesis demonstrates constraints as useful in understanding, especially in the context of problem structures and their respective design spaces. As a form of constraint, optimisation objectives are also presented in this thesis as a means of exposing and handling complexity when applied as constrained optimisation for focusing designing efforts. Above all, this thesis advocates the use of constraint-based thinking and simplicity towards enhancing and supporting designing process.