The flexibility of welded joints is an important issue in design of car bodies. Two generic, 3-D, design-oriented models (simple and complex) are developed to represent the compliant behavior of multibranch flexible joints. The simple model consists of torsional springs restraining the relative rotation of the joint branches in the three planes, while all branches are assumed to be rigidly connected in translation. Coupling between motions in different planes is neglected. The complex model accounts for such coupling. A statistical system identification method is proposed for inferring the model parameters from the static response of the structure. The method is demonstrated by applying it to a simple cube frame structure and a car body. Finally, the two models are compared in terms of their ability to predict static response. / Ph. D.

As widespread as Science, Technology, Engineering, and Math (STEM) initiatives and reforms are today in education, a rudimentary problem with these endeavors is being overlooked. In general, education programs and school districts are failing to ensure that elementary teachers who provide children's early academic experiences have the appropriate knowledge of and proclivity toward STEM subjects. This issue is further compounded by the focus centered on mathematics due to accountability requirements leaving very little emphasis on science, and most often, the exclusion of technology and engineering instruction from the curriculum (Blank, 2012; Cunningham, 2009; Lederman and Lederman, 2013; Lewis, Harshbarger, and Dema, 2014; Walker, 2014). At the elementary level, the lack of science instruction and professional development generates a weakness for both pre- and in-service teachers and prompts elevated concerns about teaching science (Goodrum, Cousins, and Kinnear, 1992; Anderson, 2002). Research (Lewis, 1999/2006; Wells, 2014) suggests that one way to address this weakness is through the technological/engineering designed-based approach within the context of integrative STEM education. The purpose of the study was to gain an understanding of change in science instructional content and practice through professional development that educates elementary teachers to implement Technological/Engineering Design Based Learning (T/E DBL) as part of teaching science. The research design was a multiple case study which adhered to a concurrent mixed method approach (Teddlie, and Tashakkori, 2006; Yin, 2003),with four participants who were recruited because of their availability and their grade level teaching assignment that correlated to an analysis of the 2013 science state accountability test, Standards of Learning (Pyle, 2015). Data collected from surveys were analyzed using descriptive and inferential statistics. These data were corroborated with a sweep instrument and assessment rubric analyses, and interview responses to validate the results. Findings from this study revealed that professional development model used in this study was clearly effective in getting elementary teachers to implement T/E DBL. The participants were better able to integrate T/E DBL when planning and designing instructional units and had an improved understanding of the science concepts they were teaching. / Ed. D.

Architecture and engineering are two professions whose concerns are often contradictory and in conflict. This situation has sometimes impaired the professions in responding to the client's needs. The encouragement of a commonality of concerns could act to enrich the quality of each profession's work. The origins of the problem lie in the past attitudes, social roles, and training of designers. These aspects were a response to past social stimuli and have continued to today. While an alteration of social roles would be problemmatic, the training process and attitudes of the professions are possible grounds for change. Educational institutions could play a major role in this redirection of concerns. A need for encouraging commonality of concerns lies in the designer's potential role in addressing environmental issues. The relationship between the built enviornment and life-style could be utilized in encouraging a more environmentally conscious society. This goal could be reaiized if architects and engineers understood the strength of design protentialities afforded by a commonality of concerns. / Master of Architecture

Research on engineering design is a core area of concern within engineering education, and a fundamental understanding of how engineering students approach and undertake design is necessary in order to develop effective design models and pedagogies. This dissertation contributes to scholarship on engineering design by addressing a critical, but as yet underexplored, problem: how does the context in which students design shape their design practices? Using a qualitative study comprising of video data of design sessions, focus group interviews with students, and archives of their design work, this research explored how design decisions and actions are shaped by context, specifically the context of higher education. To develop a theoretical explanation for observed behavior, this study used the "nested structuration" framework proposed by Perlow, Gittell, & Katz (2004). This framework explicated how teamwork is shaped by mutually reinforcing relationships at the individual, organizational, and institutional levels. I appropriated this framework to look specifically at how engineering students working on a course-related design project identify constraints that guide their design and how these constraints emerge as students interact while working on the project. I first identified and characterized the parameters associated with the design project from the student perspective and then, through multi-case studies of four design teams, I looked at the role these parameters play in student design practices. This qualitative investigation of first-year engineering student design teams revealed mutual and interconnected relationships between students and the organizations and institutions that they are a part of. In addition to contributing to research on engineering design, this work provides guidelines and practices to help design educators develop more effective design projects by incorporating constraints that enable effective design and learning. Moreover, I found that when appropriated in the context of higher education, multiple sublevels existed within nested structuration's organizational context and included course-level and project-level factors. The implications of this research can be used to improve the design of engineering course projects as well as the design of research efforts related to design in engineering education. / Ph. D.

Increased competition and the scarcity of resources has forced recognition of the significant potential of design to increase the effectiveness and efficiency of the resulting product, system, or structure. Moreover, the design process itself is undergoing a metamorphosis. Its largely sequential nature is giving way to greater concurrency and to the consideration earlier of downstream issues such as production, operation, and retirement. A complete engineering design morphology, enhanced by a sound engineering design evaluation methodology, can enable the realization of systems that meet user needs more effectively and efficiently. Isolated groups are researching diverse ways to better integrate design evaluation within the engineering design process. The need is for increased communication between these research groups for mutual benefit. A representative set of design evaluation methodologies is studied and critically reviewed in this thesis. This work is a step towards increased understanding between the different "schools of thought" and a baseline for further research. / Master of Science

Design procedures are developed that combine both the finite element method and the transfer matrix method in design. These procedures were drawn up as a result of the analysis of a large continuous mining machine to be produced by Fairchild International. Combining the methods allowed the analysis to be split into smaller jobs. Two examples are given. The first example divides the machine into a number of separate finite element analyses where the internal loads on each component are determined by the transfer matrix method. The second example analyzes the transition region between each of the separate finite element analysis. Utilizing both methods in design reduced computer usage costs. / Master of Science

This thesis presents the development of an interactive graphics interface for MECSYN, a planar mechanism synthesis program. The purpose of this work is to produce a dynamic graphics interface, independent of a graphics device and providing a high level of user interaction. To achieve this, the proposed three-dimensional graphics standard PHIGS (Programmers Hierarchical Interactive Graphics System) is used for graphics support software. An overview of the synthesis theory is presented. The program structure is described and presented along with a listing of the graphics and interface routines of the program to aid in future development of the program (synthesis routines are not included). Several examples illustrating the features and use of the program have been included. / Master of Science

A general inverse design procedure has been developed to use optimization techniques and generic surface descriptions for the purpose of aerodynamic shape design. A variety of flow regimes are examined from 2-D inviscid, subsonic cases to 3-D turbulent, supersonic problems. Surface descriptions have been generalized through the use of B-splines to model a variety of curves and shapes with a minimum of parameters. The process uses a computational fluid dynamics program, GASP (the General Aerodynamic Simulation Program), and several iterative and optimization techniques to examine bodies of interest. A 2-D inviscid, subsonic airfoil test case demonstrates the ability of the procedure to solve problems governed by elliptic equations. A 3-D, viscous, compressible flow over a forebody/canopy model of a supersonic fighter and its comparison to test data establishes the ability of the method to solve practical problems of interest. Several other test cases are performed, including an axi-symmetric power law body and a 3-D elliptic cone. Unconstrained multi-parameter optimizations have been quite successful in matching target pressure coefficients and reproducing target body shapes. / Ph. D.

An automated procedure for designing minimum-weight composite plates subject to a local damage constraint under tensile and compressive loadings has been developed. A strain based criterion was used to obtain fracture toughness of cracked plates under tension. Results of an experimental investigation of the effects of simulated through-the-thickness cracks on the buckling, postbuckling, and failure characteristics of composite flat plates are presented. A model for kinking failure of fibers at the crack tip was developed - for compression loadings. A finite element program based on linear elastic fracture mechanics for calculating stress intensity factor (SIF) was incorporated in the design cycle. A general purpose mathematical optimization algorithm was used for the weight minimization. Analytical sensitivity derivatives of the SIF, obtained by employing the adjoint variable technique, were used to enhance the computational efficiency of the procedure. Design results for both unstiffened and stiffened plates are presented. / Ph. D.

<p dir="ltr">Phenylalanine (Phe) is an essential amino acid that has uses in the feed, food and pharmaceutical industries. There is a large and growing market for Phe as a precursor to the production of artificial sweetener. Industrially, Phe is produced by feeding glucose to genetically modified strains of heterotrophic organisms such as <i>E. coli </i>or Corynebacterium in a stainless-steel fermenter. Cyanobacteria are photosynthetic microalgae which could replace heterotrophic production thereby reducing land use for crops required for glucose production. SYN-PHE, a strain of <i>Synechococcus</i> elongatus sp. PCC 11801 which was previously developed in the Morgan lab at Purdue University, produces Phe at 1 g/L in 3 days in shake flask cultures. In this thesis, a techno-economic analysis of Phe production by <i>E. coli </i>and SYN-PHE were compared. Results indicate that Phe produced by SYN-PHE is a promising competitor of <i>E. coli </i>produced Phe at an industrial scale. Further strain engineering to improve the titer of Phe is needed to be economically competitive. Additionally, efforts are needed for low capital cost photobioreactors that can enable both high biomass concentrations and high Phe titers.</p>