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Doctor of Philosophy / Department of Industrial & Manufacturing Systems Engineering / Shuting Lei / This study experimentally and numerically investigates laser assisted milling (LAMill) of silicon nitride ceramics. Experiments are conducted to study the machinability of Si3N4 under LAMill. The effects of temperature on cutting forces, tool wear, surface integrity, edge chipping and material removal mechanisms are investigated. It is shown that when temperature increases, cutting force and tool wear are significantly decreased, surface integrity is improved, chip size is increased and material removal demonstrates more plastic characteristics. The mechanisms of edge chipping at elevated temperature are investigated theoretically and experimentally. When temperature is above the softening point and below the brittle/ductile transition temperature, the mechanism is mainly through softening. When temperature is above the brittle/ductile transition temperature, toughening mechanism contributes significantly to the reduced edge chipping. The coupled effect of softening and toughening mechanisms shows that temperature range between 1200 to 1400°C has the most significant effect to reduce edge chipping. Distinct element method (DEM) is applied to simulate the micro-mechanical behavior of Si3N4. First, quantitative relationships between particle level parameters and macro-properties of the bonded particle specimens are obtained, which builds a foundation for simulation of Si3N4. Then, extensive DEM simulations are conducted to model the material removal of machining Si3N4. The simulation results demonstrate that DEM can reproduce the conceptual material removal model summarized from experimental observations, including the initiation and propagation of cracks, chip formation process and material removal mechanisms. It is shown that material removal is mainly realized by propagation of lateral cracks in machining of silicon nitride. At the elevated temperature under laser assisted machining, lateral cracks are easier to propagate to form larger machined chips, there are fewer and smaller median cracks therefore less surface/subsurface damage, and crushing-type material removal is reduced. The material removal at elevated temperature demonstrates more plastic characteristics. The numerical results agree very well with experimental observations. It shows that DEM is a promising method to model the micro-mechanical process of machining Si3N4.

Doctor of Philosophy / Department of Industrial & Manufacturing Systems Engineering / Zhijian Pei / Titanium alloy is one of the most important materials used in major segments of industries such as aerospace, automobile, sporting goods, medical and chemical. Market survey has stated that the titanium shipment in the USA has increased significantly in last two decades, indicating its increased usage. Industries are always under tremendous pressure to meet the ever-increasing demand to lower cost and improve quality of the products manufactured from titanium alloy. Similar to titanium alloys, silicon carbide and dental ceramics are two important materials used in many applications. Rotary ultrasonic machining (RUM) is a non-traditional machining process that combines the material removal mechanisms of diamond grinding and ultrasonic machining. It comprises of a tool mounted on a rotary spindle attached to a piezo-electric transducer to produce the rotary and ultrasonic motion. No study has been reported on RUM of titanium alloy, silicon carbide and dental ceramics. The goal of this research was to provide new knowledge of machining these hard-to-machine materials with RUM for further improvements in the machining cost and surface quality. A thorough research has been conducted based on the feasibility study, effects of tool variables, effects of machining variables and wheel wear mechanisms while RUM of titanium alloy. The effects of machining variables (such as spindle speed, feed rate, ultrasonic vibration power) and tool variables (grit size, diamond grain concentration, bond type) have been studied on the output variables (such as cutting force, material removal rate, surface roughness, chipping size) and the wheel wear mechanisms for titanium alloy. Feasibility of machining silicon carbide and dental ceramics is also conducted along with a designed experimental study.

Thesis (M.S.)--Mississippi State University. Department of Industrial Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2009. / Includes bibliographical references.

Thesis (M.S.)--State University of New York at Binghamton, Department of Systems Science and Industrial Engineering, 2009. / Includes bibliographical references (leaves: 150-155).

Doctor of Philosophy / Department of Industrial and Manufacturing Systems Engineering / Bradley Kramer / This research shows that industry and company related performance indicators enhance the business valuation process by providing a broader, more encompassing view of overall corporate health and a better understanding of improvement opportunity areas within a company. To incorporate performance indicators in the business valuation process, new methodologies are required to integrate the non-financial and soft data with the typical financial information used in business valuation. This requires a “re-think” of the standard business valuation process and the exploration and application of other methods and analytical techniques. The results of this research are the definition of a problem type and the development of a new business valuation process. The problem structure has as inputs industry specific performance metrics grouped into three primary areas Production Processes, Products/Services and Marketability and Management, a fuzzy logic model with fuzzy and approximate relationships between performance metrics and financial information and crisp financial information as output. The framework for a fuzzy logic model was developed and is used to approximate relationships and model a non-linear environment. The resulting crisp financial information is then input and integrated into the traditional business valuation process. The process was demonstrated with an example production company and with data from two regional airlines. A step-by-step example of the process was provided using the production company example to demonstrate how the results are generated and integrated with DCF business valuation. Heuristics to identify areas to improve company performance were described. Two regional airlines, individually and combined, were tested with actual data using the original fuzzy logic model structure and then the original fuzzy logic model structure was revised and new results generated. Tuning the model showed an improvement in the business valuation process performance. The benefits from this research include the definition of a new class of problems and a process to solve problems of this nature. The insights gained from this research can be applied in major disciplines such as accounting, business and finance, engineering and decision theory.

Corrosion represents the single most frequent cause for product replacement or loss of product functionality with a 5% coat to the industrial revenue generation of any country in this dissertation the efficacy of using filled coatings as a protection coating are investigated. Fillers disrupt the polymer-substrate coating interfacial area and lead to poor adhesion. Conflicting benefits of increasing surface hardness and corrosion with long term durability through loss of adhesion to the substrate are investigated. The effects of filler type, filler concentration and exposure to harsh environments such as supercritical carbon dioxide on salt water corrosion are systematically investigated. The constants maintained in the design of experiments were the substrate, AISI-SAE 1018 steel substrate, and the corrosive fluid synthetic sea salt solution (4.2 wt%) and the polymer, Bismaleimide (BMI). Adhesion strength through pull-off, lap shear and shear peel tests were determined. Corrosion using Tafel plots and electrochemical impedance spectroscopy was conducted. Vickers hardness was used to determine mechanical strength of the coatings. SEM and optical microscopy were used to examine dispersion and coating integrity. A comparison of fillers such as alumina, silica, hexagonal boron nitride, and organophilic montmorillonite clay (OMMT) at different concentrations revealed OMMT to be most effective with the least decrease in adhesion from filler-substrate contact. Subsequently examining filler concentration, a 3 wt% OMMT was found to be most effective. A comparison of unmodified and modified BMI with 3 wt% OMMT exposed and not exposed to supercritical carbon dioxide showed that the BMI provided better corrosion protection; however, OMMT provided better wear, shear, and hardness performance.

Entscheidungen im Industrial Design werden vorrangig auf Basis vorab gestalteter Designentwürfe auf der gehobenen Management- und auf Geschäftsführerebene getroffen. In diesen Unternehmensebenen finden sich nur wenige im gestalterischen Bereich ausgebildete Führungskräfte (Schoenberger 2011). Die Entscheidungen über kreative Bereiche der Produktentwicklung werden daher meist von Personen designferner Disziplinen getroffen. Dieser Umstand beinhaltet zum einen eine große Unsicherheit in Bezug auf die richtige Designentscheidung im unternehmerischen Sinne und zum anderen führt es zu zögerlichen und weniger abgesicherten Entscheidungen bei gestalterischen Fragestellungen. Die Subjektivität, die bei diesen Entscheidungen eine nicht zu unterschätzende Rolle spielt, erschwert eine sachliche Bewertung und Folgenabschätzung einer Designentscheidung. Diese haben jedoch im weiteren Produktentwicklungsprozess (PEP) und vor allem bei dessen Endergebnis einen großen Einfluss auf die Wirtschaftlichkeit eines Produkts und dessen möglichen Erfolg auf dem Markt. Im klassischen Innovationsmanagement werden die Designkriterien nicht oder nur unzureichend berücksichtigt. So weist beispielsweise die Innovationscheckliste nach Hauschildt/Salomo kein einziges Designkriterium auf, wenn es um die Bewertung einer möglichen Innovation geht (Hauschildt und Salomo 2011).

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