Current Search: Engineering Management (x)
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(1 - 12 of 12)
- Title
- A REAL OPTION STRATEGIC SCORECARD DECISION FRAMEWORK FOR IT PROJECT SELECTION.
- Creator
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Munoz, Cesar, Rabelo, Luis, University of Central Florida
- Abstract / Description
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ABSTRACT The problem of project selection is of significant importance in management of information systems. Almost $2 trillion is spent worldwide every year on IT projects, with over $600 billion spent in the US alone. Traditionally, managers have being using the classical net present value (NPV) method in conjunction with multicriteria scoring models for ROI analysis and selection of IT project investments The multicriteria models use ad-hoc evaluation criteria to assign priority weights...
Show moreABSTRACT The problem of project selection is of significant importance in management of information systems. Almost $2 trillion is spent worldwide every year on IT projects, with over $600 billion spent in the US alone. Traditionally, managers have being using the classical net present value (NPV) method in conjunction with multicriteria scoring models for ROI analysis and selection of IT project investments The multicriteria models use ad-hoc evaluation criteria to assign priority weights and then rate the alternatives against each criterion. These models have two limitations. First, the criteria and weights are based on subjective judgments, allowing the introduction of politics in the information management decision process and the generation of arbitrary results. Second, the classical approach uses deterministic estimations of the cost, benefits and the returns of the projects, without considering the impact of uncertainty and risk in the business decisions. This research proposed a better alternative for ROI analysis and selection of IT projects using a real option strategic scorecard (ROSS) approach. In contrast with traditional methodologies and previous research work, the ROSS decision framework uses a more comprehensive, axiomatic approach for systematically measuring both the business value and the strategic implications of IT project investments. The ROSS approach integrates in a unified IT project management decision framework the best elements of real option theory, strategic balanced scorecards, Monte Carlo simulations and analytical network processes to fully analyzes the effect of uncertainty and risk in the IT investment decisions. In addition, the ROSS approach complies with the critical success factors that have being identified in the literature for validation of IT decision frameworks. The main benefit of the ROSS approach is to enable managers to better compare and rank projects in the IT portfolio, optimizing the ROI analysis and selection of information system projects.
Show less - Date Issued
- 2006
- Identifier
- CFE0001331, ucf:46975
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001331
- Title
- Efficient techniques for management and delivery of video data.
- Creator
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Oh, Junghwan, Hua, Kien A., Engineering and Computer Science
- Abstract / Description
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University of Central Florida College of Engineering Thesis; The rapid advances in electronic imaging, storage, data compression telecommunications, and networking technology have resulted in a vast creation and use of digital videos in many important applications such as digital libraries, distance learning, public information systems, electronic commerce, movie on demand, etc. This brings about the need for management as well as delivery of video data. Organizing and managing video data,...
Show moreUniversity of Central Florida College of Engineering Thesis; The rapid advances in electronic imaging, storage, data compression telecommunications, and networking technology have resulted in a vast creation and use of digital videos in many important applications such as digital libraries, distance learning, public information systems, electronic commerce, movie on demand, etc. This brings about the need for management as well as delivery of video data. Organizing and managing video data, however, is much more complex than managing conventional text data due to their semantically rich and unstructured contents. Also, the enormous size of video files requires high communication bandwidth for data delivery. In this dissertation, I present the following techniques for video data management and delivery. Decomposing video into meaningful pieces (i.e., shots) is a very fundamental step to handling the complicated contents of video data. Content-based video parsing techniques are presented and analyzed. In order to reduce the computation cost substantially, a non-sequential approach to shot boundary detection is investigated. Efficient browsing and indexing of video data are essential for video data management. Non-linear browsing and cost-effective indexing schemes for video data based on their contents are described and evaluated. In order to satisfy various user requests, delivering long videos through the limited capacity of bandwidth is challenging work. To reduce the demand on this bandwidth, a hybrid of two effective approaches, periodic broadcast and scheduled multicast, is discussed and simulated. The current techniques related to the above works are discussed thoroughly to explain their advantages and disadvantages, and to make the new improved schemes. The substantial amount of experiments and simulations as well as the concepts are provided to compare the introduced techniques with the other existing ones. The results indicate that they outperform recent techniques by a significant margin. I conclude the dissertation with a discussing of future research directions.
Show less - Date Issued
- 2000
- Identifier
- CFR0001719, ucf:52918
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0001719
- Title
- A Holistic Framework for Transitional Management.
- Creator
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Elattar, Ahmed, Rabelo, Luis, Pazour, Jennifer, Mollaghasemi, Mansooreh, Ajayi, Richard, University of Central Florida
- Abstract / Description
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For all business organizations, there comes a time when a change must take place within their eco-system. It consumes a great deal of thought and planning to ensure that the right decision is made as it could alter the entire course of their business for a number of years to come. This change may appear in the form of a brilliant CEO reaching the age of retirement, or an unsuccessful Managing Director being asked to leave before fulfilling the term of her contract. Regardless of the cause, a...
Show moreFor all business organizations, there comes a time when a change must take place within their eco-system. It consumes a great deal of thought and planning to ensure that the right decision is made as it could alter the entire course of their business for a number of years to come. This change may appear in the form of a brilliant CEO reaching the age of retirement, or an unsuccessful Managing Director being asked to leave before fulfilling the term of her contract. Regardless of the cause, a transition must occur in which a suitable successor is chosen and put into place while minimizing costs, satisfying stakeholders, ensuring that the successor has been adequately prepared for their new position, and minimizing work place gossip, among other things. It is also important to understand how the nature of the business, as well as its financial standing, effects such a transition.Engineering and management principles come together in this study to ensure that organizations going through such a change are on the right course. As the problem of transitional management is not one of concrete values and contains many ambiguous concepts, one way to tackle the problem is by utilizing various industrial engineering methodologies that allow these companies to systematically begin preparing for such a change. By default, organizational strategy has to change, technology is continually being renewed and it becomes very hard for the same leader to constantly implement new and innovative developments.Organizations today have a very poor understanding of where they currently stand and as a result the cause for a company's lack of profitability is often overlooked with time and money being wasted in an attempt to fix something that is not broken. To be able to look at the bigger picture of an organization and from there begin to close in on the main problems causing a negative impact, the Matrix of Change is used and takes in many factors to layout an accurate representation of the direction in which an organization should be headed and how it can continue to grow and remain successful. The Theory of Constraints on the other hand is used here as a step-by-step guide allowing companies to be better organized during times of change. And System Dynamics modeling is where these companies can begin to simulate and solve the dilemma of transitional management using causal loop diagrams and stock and flow diagrams.Through such tools a framework can begin to be developed, one that is valued by corporations and continually reviewed. Several case studies, simulation modeling, and a panel of experts were used in order to demonstrate and validate this framework.
Show less - Date Issued
- 2014
- Identifier
- CFE0005160, ucf:50708
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005160
- Title
- Crash quality- an approach for evaluating spending on quality improvement initiatives.
- Creator
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Ferreira, Labiche, Hosni, Yasser A., Engineering
- Abstract / Description
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University of Central Florida College of Engineering Thesis; The quality movement has become popular among corporations big and small for one reason: empirical evidence suggests that quality and productivity (and hence profitability) are linked. Unfortunately, while many firms accept that quality and productivity go together, few actually track the gains associated with their quality improvement programs. Companies also tend to spend on quality improvement with no indication of estimation of...
Show moreUniversity of Central Florida College of Engineering Thesis; The quality movement has become popular among corporations big and small for one reason: empirical evidence suggests that quality and productivity (and hence profitability) are linked. Unfortunately, while many firms accept that quality and productivity go together, few actually track the gains associated with their quality improvement programs. Companies also tend to spend on quality improvement with no indication of estimation of the impact of funding on the targeted process. It would be of great value to know: (1) the impact of spending to enhance the product/process quality level, and (2) the point at which expenditures for quality improvement are not economical. This research involves modeling the quality level of a product composed of integrated components/processes and the costs associated with quality improvement. Presented in this research is a methodology for determining the point at which the target quality level is reached. This point signifies when future spending should be re-directed. The research defines this point as the "Crash Quality Point (CQP)." Cases of a single process level and double level three-stage process are modeled to conceptualize CQP. The finding from the output analysis reveal that the quality level approaches the target level at varying points in time. Any spending beyond this point does not have an impact on the quality level compared to the period prior to the Crash Quality Point. Spending past this point is futile and these funds could be spent on the quality improvement projects. The special case modeled also illustrates the use of this tool in the selection of processes for improvements based on the quality level of the process. This is an added advantage in scenarios where funds are limited and management is constrained to improve process quality with limited funds. Using a real world example validates the proposed CQP methodology. The results of the validation indicate that the model developed can assist managers in forecasting the budget requirements for quality spending based on the quality improvement goals. The tool also enables managers to estimate the point in time at which allocations of funds may be directed for process reengineering. The CQP method will enable quality improvement professionals to determine the economical viability and the limits in expenditures on quality improvement. It enables managers to evaluate spending alternatives and approximate when the point of diminishing return is reached.
Show less - Date Issued
- 2000
- Identifier
- CFR0011594, ucf:53046
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0011594
- Title
- An Engineering Analytics Based Framework for Computational Advertising Systems.
- Creator
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Chen, Mengmeng, Rabelo, Luis, Lee, Gene, Keathley, Heather, Rahal, Ahmad, University of Central Florida
- Abstract / Description
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Engineering analytics is a multifaceted landscape with a diversity of analytics tools which comes from emerging fields such as big data, machine learning, and traditional operations research. Industrial engineering is capable to optimize complex process and systems using engineering analytics elements and the traditional components such as total quality management. This dissertation has proven that industrial engineering using engineering analytics can optimize the emerging area of...
Show moreEngineering analytics is a multifaceted landscape with a diversity of analytics tools which comes from emerging fields such as big data, machine learning, and traditional operations research. Industrial engineering is capable to optimize complex process and systems using engineering analytics elements and the traditional components such as total quality management. This dissertation has proven that industrial engineering using engineering analytics can optimize the emerging area of Computational Advertising. The key was to know the different fields very well and do the right selection. However, people first need to understand and be experts in the flow of the complex application of Computational Advertising and based on the characteristics of each step map the right field of Engineering analytics and traditional Industrial Engineering. Then build the apparatus and apply it to the respective problem in question.This dissertation consists of four research papers addressing the development of a framework to tame the complexity of computational advertising and improve its usage efficiency from an advertiser's viewpoint. This new framework and its respective systems architecture combine the use of support vector machines, Recurrent Neural Networks, Deep Learning Neural Networks, traditional neural networks, Game Theory/Auction Theory with Generative adversarial networks, and Web Engineering to optimize the computational advertising bidding process and achieve a higher rate of return. The system is validated with an actual case study with commercial providers such as Google AdWords and an advertiser's budget of several million dollars.
Show less - Date Issued
- 2018
- Identifier
- CFE0007319, ucf:52118
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007319
- Title
- A Hybrid Simulation Framework of Consumer-to-Consumer Ecommerce Space.
- Creator
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Joledo, Oloruntomi, Rabelo, Luis, Lee, Gene, Elshennawy, Ahmad, Ajayi, Richard, University of Central Florida
- Abstract / Description
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In the past decade, ecommerce transformed the business models of many organizations. Information Technology leveled the playing field for new participants, who were capable of causing disruptive changes in every industry. (")Web 2.0(") or (")Social Web(") further redefined ways users enlist for services. It is now easy to be influenced to make choices of services based on recommendations of friends and popularity amongst peers. This research proposes a simulation framework to investigate how...
Show moreIn the past decade, ecommerce transformed the business models of many organizations. Information Technology leveled the playing field for new participants, who were capable of causing disruptive changes in every industry. (")Web 2.0(") or (")Social Web(") further redefined ways users enlist for services. It is now easy to be influenced to make choices of services based on recommendations of friends and popularity amongst peers. This research proposes a simulation framework to investigate how actions of stakeholders at this level of complexity affect system performance as well as the dynamics that exist between different models using concepts from the fields of operations engineering, engineering management, and multi-model simulation. Viewing this complex model from a systems perspective calls for the integration of different levels of behaviors. Complex interactions exist among stakeholders, the environment and available technology. The presence of continuous and discrete behaviors coupled with stochastic and deterministic behaviors present challenges for using standalone simulation tools to simulate the business model.We propose a framework that takes into account dynamic system complexity and risk from a hybrid paradigm. The SCOR model is employed to map the business processes and it is implemented using agent based simulation and system dynamics. By combining system dynamics at the strategy level with agent based models of consumer behaviors, an accurate yet efficient representation of the business model that makes for sound basis of decision making can be achieved to maximize stakeholders' utility.
Show less - Date Issued
- 2016
- Identifier
- CFE0006122, ucf:51171
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006122
- Title
- CONTRIBUTIONS BY INDIVIDUAL AND GROUP STRATEGIES FOR ORGANIZATIONAL LEARNING IN ARCHITECTURAL, ENGINEERING, AND CONSTRUCTION FIRMS.
- Creator
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Beaver, Robert, Kotnour, Timothy, University of Central Florida
- Abstract / Description
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Organizations with multiple operating requirements require support functions to assist in execution of strategic goals. This effort, in turn, requires management of engineering activities in control of projects and in sustaining facilities. High level strategies include employing engineering support that consists of a project management function encompassing technical and managerial disciplines. The architecture/engineering, and construction office (AEC) is the subject of this research....
Show moreOrganizations with multiple operating requirements require support functions to assist in execution of strategic goals. This effort, in turn, requires management of engineering activities in control of projects and in sustaining facilities. High level strategies include employing engineering support that consists of a project management function encompassing technical and managerial disciplines. The architecture/engineering, and construction office (AEC) is the subject of this research. Engineering and construction oriented organizations have experienced challenges to their abilities to learn and grow. This has potential detrimental implications for these organizations if support functions cannot keep pace with changing objectives and strategy. The competitive nature and low industry margins as well as uniqueness of projects as challenges facing engineering and construction. The differentiated nature of projects tasks also creates a need for temporary and dedicated modes of operation and thereby tends to promote highly dispersed management practices that do not dovetail very well with other organizational processes. Organizational learning is a means to enhance and support knowledge management for improving performance. The problem addressed through this research is the gap between desired and achieved individual and group learning by members of the AEC, and the members' abilities to distinguish between the need for adaptive learning or innovation. This research addresses learning by individuals and groups, and the strategies employed through an empirical study (survey). A conceptual model for organizational learning contributions by individuals and groups is presented and tested for confirmation of exploitive or explorative learning strategies for individuals, and directions composed of depth and breadth of learning. Strategies for groups are tested for internal or external search orientations and directions toward the single or multi-discipline unit. The survey is analyzed by method of principal components extraction and further interpreted to reveal factors that are correlated by Pearson product moment coefficients and tested for significance for potential relationships to factors for outcomes. Correlation across dependent variables prevented interpretation of the most significant factors for group learning strategies. However, results provide possible support for direction in supporting processes that promote networking among individuals and group structures that recognize the dual nature of knowledge - that required for technical competency and that required for success in the organization. Recommendations for practitioners include adjustments to knowledge acquisition direction, promoting external collaboration among firms, and provision of dual succession pathways through technical expertise or organizational processes for senior staff.
Show less - Date Issued
- 2009
- Identifier
- CFE0002682, ucf:48194
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002682
- Title
- IMPROVING BUSINESS PERFORMANCE THROUGH THE INTEGRATION OF HUMAN FACTORS ENGINEERING INTO ORGANIZATIONS USING A SYSTEMS ENGINEERING APPROACH.
- Creator
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Philippart, Monica, Karwowski, Waldemar, University of Central Florida
- Abstract / Description
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Most organizations today understand the valuable contribution employees as people (rather than simply bodies) provide to their overall performance. Although efforts are made to make the most of the human in organizations, there is still much room for improvement. Focus in the reduction of employee injuries such as cumulative trauma disorders rose in the 80's. Attempts at increasing performance by addressing employee satisfaction through various methods have also been ongoing for several...
Show moreMost organizations today understand the valuable contribution employees as people (rather than simply bodies) provide to their overall performance. Although efforts are made to make the most of the human in organizations, there is still much room for improvement. Focus in the reduction of employee injuries such as cumulative trauma disorders rose in the 80's. Attempts at increasing performance by addressing employee satisfaction through various methods have also been ongoing for several years now. Knowledge Management is one of the most recent attempts at controlling and making the best use of employees' knowledge. All of these efforts and more towards that same goal of making the most of people's performance at work are encompassed within the domain of the Human Factors Engineering/Ergonomics field. HFE/E provides still untapped potential for organizational performance as the human and its optimal performance are the reason for this discipline's being. Although Human Factors programs have been generated and implemented, there is still the need for a method to help organizations fully integrate this discipline into the enterprise as a whole. The purpose of this research is to develop a method to help organizations integrate HFE/E into it business processes. This research begun with a review of the ways in which the HFE/E discipline is currently used by organizations. The need and desire to integrate HFE/E into organizations was identified, and a method to accomplish this integration was conceptualized. This method consisted on the generation of two domain-specific ontologies (a Human Factors Engineering/Ergonomics ontology, and a Business ontology), and mapping the two creating a concept map that can be used to integrate HFE/E into businesses. The HFE/E ontology was built by generating two concept maps that were merged and then joined with a HFE/E discipline taxonomy. A total of four concept maps, two ontologies and a taxonomy were created, all of which are contributions to the HFE/E, and the business- and management-related fields.
Show less - Date Issued
- 2008
- Identifier
- CFE0002445, ucf:47716
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002445
- Title
- Species and habitat interactions of the gopher tortoise: A keystone species?.
- Creator
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Catano, Christopher, Hinkle, Charles, Stout, I, Jenkins, David, University of Central Florida
- Abstract / Description
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Species-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their...
Show moreSpecies-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their communities and habitats have rarely been empirically quantified. I examined how habitat structure influences tortoise abandonment of burrows and how tortoise densities influence non-volant vertebrate community diversity. Tortoise burrow abandonment is directly influenced by canopy closure, with each percent increase in canopy cover relating to a ~2% increase in the probability of burrow abandonment. In addition, tortoise burrow density was positively correlated with diversity and evenness, but not species richness. This influence was directly proportional to burrow density, supporting a dominance role for this species and rejecting the commonly asserted keystone species mechanism. I also quantified the influence of tortoises in influencing diversity relative to other environmental and habitat variables. Through this research, I have demonstrated that disturbance and habitat structure are important, but diversity responds most to density of burrows in the habitat. These findings demonstrate the intricate relationships interacting to maintaining diversity in sandhill systems. In particular, habitat change leading to declines of gopher tortoises may have drastic negative impacts on vertebrate species diversity.
Show less - Date Issued
- 2012
- Identifier
- CFE0004526, ucf:49246
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004526
- Title
- Factors Affecting Systems Engineering Rigor in Launch Vehicle Organizations.
- Creator
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Gibson, Denton, Karwowski, Waldemar, Rabelo, Luis, Kotnour, Timothy, Kern, David, University of Central Florida
- Abstract / Description
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Systems engineering is a methodical multi-disciplinary approach to design, build, and operate complex systems. Launch vehicles are considered by many extremely complex systems that have greatly impacted where the systems engineering industry is today. Launch vehicles are used to transport payloads from the ground to a location in space. Satellites launched by launch vehicles can range from commercial communications to national security payloads. Satellite costs can range from a few million...
Show moreSystems engineering is a methodical multi-disciplinary approach to design, build, and operate complex systems. Launch vehicles are considered by many extremely complex systems that have greatly impacted where the systems engineering industry is today. Launch vehicles are used to transport payloads from the ground to a location in space. Satellites launched by launch vehicles can range from commercial communications to national security payloads. Satellite costs can range from a few million dollars to billions of dollars. Prior research suggests that lack of systems engineering rigor as one of the leading contributors to launch vehicle failures. A launch vehicle failure could have economic, societal, scientific, and national security impacts. This is why it is critical to understand the factors that affect systems engineering rigor in U.S. launch vehicle organizations.The current research examined organizational factors that influence systems engineering rigor in launch vehicle organizations. This study examined the effects of the factors of systems engineering culture and systems engineering support on systems engineering rigor. Particularly, the effects of top management support, organizational commitment, systems engineering support, and value of systems engineering were examined. This research study also analyzed the mediating role of systems engineering support between top management support and systems engineering rigor, as well as between organizational commitment and systems engineering rigor. A quantitative approach was used for this. Data for the study was collected via survey instrument. A total of 203 people in various systems engineering roles in launch vehicle organizations throughout the United States voluntarily participated. Each latent construct of the study was validated using confirmatory factor analysis (CFA). Structural equation modeling (SEM) was used to examine the relationships between the variables of the study. The IBM SPSS Amos 25 software was used to analyze the CFA and SEM.
Show less - Date Issued
- 2019
- Identifier
- CFE0007806, ucf:52348
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007806
- Title
- A Framework of Critical Success Factors for Business Organizations that Lead to Performance Excellence Based on a Financial and Quality Systems Assessment.
- Creator
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Francisco, Melissa, Elshennawy, Ahmad, Karwowski, Waldemar, Rabelo, Luis, Xanthopoulos, Petros, Weheba, Gamal, University of Central Florida
- Abstract / Description
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One of the most important tasks that business leaders undertake in order to achieve a superior market position is strategic planning. Beyond this obligation, business owners desire to maximize profit and maintain steady growth. In order to do this, resources must be invested in the most efficient way possible in order to achieve performance excellence. Adjusting business operations quickly, however, especially in times of economic uncertainty, is extremely difficult. Business leaders...
Show moreOne of the most important tasks that business leaders undertake in order to achieve a superior market position is strategic planning. Beyond this obligation, business owners desire to maximize profit and maintain steady growth. In order to do this, resources must be invested in the most efficient way possible in order to achieve performance excellence. Adjusting business operations quickly, however, especially in times of economic uncertainty, is extremely difficult. Business leaders therefore need insight into which elements of organizational improvement are most effective in order to strategically invest their resources to achieve superior performance in the most efficient way possible.This research examines the results of companies which have a demonstrated ability to achieve performance excellence as defined by the National Institute of Standards and Technology's Malcolm Baldrige Criteria for Performance Excellence. This research examined award-winning applications to determine common input factors, compared the business results of a subset of those award-winners with the overall market for a time-frame of 11 years, and then investigated the profitability, liquidity, debt management, asset management, and per share performance ratios of award-winners compared with their industry peers over 11 years as well.The main focus of this research is to determine whether participation in performance excellence best practices have created value for shareholders and business owners. This objective is achieved through the analysis of performance results of award winning companies. This research demonstrates that the integration of efforts associated with performance excellence is in-fact advantageous.
Show less - Date Issued
- 2014
- Identifier
- CFE0005331, ucf:50503
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005331
- Title
- INVESTIGATION OF PS-PVD AND EB-PVD THERMAL BARRIER COATINGS OVER LIFETIME USING SYNCHROTRON X-RAY DIFFRACTION.
- Creator
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Northam, Matthew, Raghavan, Seetha, Ghosh, Ranajay, Vaidyanathan, Raj, University of Central Florida
- Abstract / Description
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Extreme operating temperatures within the turbine section of jet engines require sophisticated methods of cooling and material protection. Thermal barrier coatings (TBCs) achieve this through a ceramic coating applied to a substrate material (nickel-based superalloy). Electron-beam physical vapor deposition (EB-PVD) is the industry standard coating used on jet engines. By tailoring the microstructure of an emerging deposition method, Plasma-spray physical vapor deposition (PS-PVD), similar...
Show moreExtreme operating temperatures within the turbine section of jet engines require sophisticated methods of cooling and material protection. Thermal barrier coatings (TBCs) achieve this through a ceramic coating applied to a substrate material (nickel-based superalloy). Electron-beam physical vapor deposition (EB-PVD) is the industry standard coating used on jet engines. By tailoring the microstructure of an emerging deposition method, Plasma-spray physical vapor deposition (PS-PVD), similar microstructures to that of EB-PVD coatings can be fabricated, allowing the benefits of strain tolerance to be obtained while improving coating deposition times. This work investigates the strain through depth of uncycled and cycled samples using these coating techniques with synchrotron X-ray diffraction (XRD). In the TGO, room temperature XRD measurements indicated samples of both deposition methods showed similar in-plane compressive stresses after 300 and 600 thermal cycles. In-situ XRD measurements indicated similar high-temperature in-plane and out-of-plane stress in the TGO and no spallation after 600 thermal cycles for both coatings. Tensile in-plane residual stresses were found in the YSZ uncycled PS-PVD samples, similar to APS coatings. PS-PVD samples showed in most cases, higher compressive residual in-plane stress at the YSZ/TGO interface. These results provide valuable insight for optimizing the PS-PVD processing parameters to obtain strain compliance similar to that of EB-PVD. Additionally, external cooling methods used for thermal management in jet engine turbines were investigated. In this work, an additively manufactured lattice structure providing transpiration cooling holes is designed and residual strains are measured within an AM transpiration cooling sample using XRD. Strains within the lattice structure were found to have greater variation than that of the AM solid wall. These results provide valuable insight into the viability of implementing an AM lattice structure in turbine blades for the use of transpiration cooling.
Show less - Date Issued
- 2019
- Identifier
- CFE0007844, ucf:52830
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007844
