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A theoretical model of design, that is universal and has a scientific basis, was developed. By doing so, it is believed that the practice of engineering design can be significantly improved. A better system of modeling designs is the missing ingredient that needs to be developed in order to improve the practice of design in the manner suggested above. Existing methodologies were reviewed to examine the current state of engineering design. This helped in developing a set of requirements for a new methodology. The potential for a scientific methodology to improve the practice of engineering design is also discussed. Developing a scientific theory of design, and showing that it meets these requirements was done to satisfy the objective. The theory takes the form of a conceptual model of design, which relates important aspects of the problem and the solution to facilitate a truly top-down hierarchical approach. A few examples are given to show how the methodology can be applied to real world design problems. As a result, a theoretical framework for design was created as a part of this research project. The new methodology, termed UTED (Unified Theory of Engineering Design), addresses many important aspects of design which are overlooked by other methodologies. A set of rules was developed, to guide the designer through the design, and allow a more scientific process to be used. Making design more scientific increases the likelihood of achieving a successful design. The primary conclusions are that the development of a scientific theory of design can be created that makes design processes faster and more efficient, and improves the quality of designs produced, meaning there is a strong potential for such a methodology to have a positive impact on the field of engineering design.

Thesis--School of Advanced Airpower Studies, Maxwell Air Force Base, Ala., 1994-95. / Title from title screen (viewed Nov. 7, 2003). "April 1996." Includes bibliographical references.

国立情報学研究所で電子化したコンテンツを使用している。

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Qaisar Shafi, Dept. of Physics & Astronomy. Includes bibliographical references.

Finite element simulation of metal cutting processes offers a cost-effective method to optimize the cutting conditions and to select the right tool material and geometry. A key input to such simulations is a constitutive model that describes material behavior during severe plastic deformation. However, the vast majority of material models used in prior work are phenomenological in nature and are usually obtained by fitting a non-physically based mathematical equation to the macro-scale stress-strain response of the material. Moreover, the deformation range covered by the stress-strain response used in the model calibration process usually falls short of the ranges typically observed in metal cutting. This thesis seeks to develop a unified material model that explicitly incorporates microstructure evolution into the constitutive law to describe the macro-scale plastic deformation response of the material valid over the range of strains, strain rates and temperatures experienced in machining. The proposed unified model is based on the underlying physics of interactions of mobile dislocations with different short and long range barriers and accounts for various physical mechanisms such as dynamic recovery and dynamic recrystallization. In addition, the inclusion of microstructure evolution into the constitutive model enables the prediction of microstructure in the chip and the machined surface. In this study, the unified material model is calibrated and validated in the severe plastic deformation regime characteristic of metal machining and is then implemented in finite element simulations to evaluate its ability to predict continuous and segmented chip formation in machining of pure metals such as OHFC copper and commercially-pure titanium (CP-Ti). Due to the physical basis of the proposed unified material model, the continuous chip formation observed in orthogonal cutting of OFHC copper is shown to be successfully predicted by the finite element model utilizing a version of the unified material model that explicitly accounts for microstructure evolution as well as dislocation drag as a plausible deformation mechanism applicable at the high strain rates common in metal cutting operations. The segmented or shear localized chip formation in orthogonal cutting of CP-Ti is also shown to be successfully simulated by the unified model after incorporating the inverse Hall-Petch effect arising from the ultrafine grain structure within the shear band. For both metals, the model is experimentally validated using flow stress data as well as machining data including cutting and thrust forces and relevant chip morphology parameters. Machining simulations carried out using the unified material model also yield useful insights into the microstructure evolution during the machining process, which is shown to be consistent with the available experimental data and the known physical understanding of severe plastic deformation behavior of the metals.

Traditionally the dominant formalist school in mathematics has considered diagrams as merely heuristic tools. However, the last few years have seen a renewed interest in visualisation in mathematics and, in particular, in diagrammatic reasoning. This has resulteQ from the increasing capabilities of modern computers, the key role that design and modelling notations play in the development process of software systems, and the emergence of the first formal diagrammatic systems. Constraint diagrams are a diagrammatic notation for expressing constraints that can be used in conjunction with the Unified Modelling Language (UML) in object-oriented modelling. Recently, full formal semantics and sound and complete inference rules have been developed for Venn-Peirce diagrams and Euler circles. Spider diagrams emerged from work on constraint diagrams. They combine and extend Venn-Peirce diagrams and Euler circles to express constraints on sets and their relationships with other sets. The spider diagram system SDI developed in this thesis extends the second Venn-Peirce system that Shin investigated, Venn II, to give lower bounds for the cardinality of the sets represented by the diagrams. A sound and complete set of reasoning rules is given. The diagrammatic system SD2 extends SD 1 so that lower and upper bounds can be inferred for the cardinalities of the set represented by the diagrams. Soundness and completeness results are also given extending the proof strategies used in SD 1. The system SD2 is also shown to be syntactically rich enough to express the negation of any diagram. Finally, the ESD2 system incorporates syntactic elements from the spider diagram notation, so that information within a diagram can be expressed more compactly, and is proved equivalent to SD2. Two important innovations are introduced with respect to Venn I, Venn II, and Higraphs: two levels of syntax - abstract and concrete - and a proof of completeness that omits the use of maximal diagram used in these systems. This work will help to provide the necessary mathematical underpinning for the development of software tools to aid the reasoning process . and the development and formalisation of more expressive diagrammatic notations.

Thesis (Ph. D.)--Northeastern University, 2009. / Title from title page (viewed June 22, 2009). Graduate School of Arts and Sciences, Dept. of Physics. Includes bibliographical references (p. 163-178).