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MECHANICAL CHARACTERIZATION OF ANISOTROPIC FUSED DEPOSITION MODELED POLYLACTIC ACID UNDER COMBINED MONOTONIC BENDING AND TORSION CONDITIONS
Title
MECHANICAL CHARACTERIZATION OF ANISOTROPIC FUSED DEPOSITION MODELED POLYLACTIC ACID UNDER COMBINED MONOTONIC BENDING AND TORSION CONDITIONS.
Creator
Santomauro, Aaron T, Gordon, Ali P., University of Central Florida
Abstract / Description
Mechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected...
Show moreMechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected to multiple monotonic loading conditions. Although empirical data has previously been captured for multi-oriented PLA under tensile and compressive loading conditions, the data has yet to be applied with regard to a representative component geometry. The tensile and compressive empirical data were ultimately used to develop elastic and yield constitutive models which aided in the characterization of PLA under torsion and bending. This representative component geometry is expected to experience a combined torsion and bending load condition in an effort to address this integral gap in the mechanical properties of multi-oriented PLA. In addition to the acquired empirical data, finite element analysis (FEA) and analytical modeling are employed to supplement the accurate modeling of future component analysis. As a result of the proposed array of experiments, the torsional and bending capabilities of PLA are forecasted to vary based on the print orientation. Lastly, the broader impact of this work is dedicated to addressing the material's capability to operate in environments which possess significant torsion and bending such as model aircraft wings and shafts for remote controlled cars.
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Date Issued
2019
Identifier
CFH2000550, ucf:45631
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000550
Regolith-Based Construction Materials for Lunar and Martian Colonies
Title
Regolith-Based Construction Materials for Lunar and Martian Colonies.
Creator
Grossman, Kevin, Seal, Sudipta, Florczyk, Stephen, Fang, Jiyu, Zhai, Lei, Leuenberger, Michael, University of Central Florida
Abstract / Description
Humankind's ambitions of exploring our solar system and parts beyond depend heavily on our ability to collect resources from local environments at our destinations rather than bringing materials on the journey. This is a concept known as in-situ resource utilization (ISRU) and it is one that has been understood by every explorer and settler in the history of humankind. Regolith on the moon and Mars has been shown to be a particularly useful resource and has the ability to provide humans with...
Show moreHumankind's ambitions of exploring our solar system and parts beyond depend heavily on our ability to collect resources from local environments at our destinations rather than bringing materials on the journey. This is a concept known as in-situ resource utilization (ISRU) and it is one that has been understood by every explorer and settler in the history of humankind. Regolith on the moon and Mars has been shown to be a particularly useful resource and has the ability to provide humans with resources including water, oxygen, construction material, fabric, radiation shielding, metals, and may more. This dissertation focuses on construction materials derived from standard regolith simulant JSC-1A, including bricks, composites, metals and modified powder materials. Sintering processes with JSC-1A were studied to determine optimal heating profiles and resulting compressive strengths. It was determined that the temperature profiles have an optimal effect on smaller particle sizes due to the larger surface area to volume ratio of small particles and sintering being a surface event. Compressive strengths of sintered regolith samples were found to be as high as 38,000 psi, which offers large utility for martian or lunar colonies. This study also investigates a method for extracting metals from regolith known as molten regolith electrolysis. The alloy of the two major metallic components of regolith, iron and silicon, has been investigated as a structural metal for colonies and a potential feedstock for novel metallic 3D printers. Parallel to these efforts, a new additive manufacturing technique designed to print metal parts in low and zero gravity environments is developed. The mechanical properties from metal parts from this technique are examined and it is determined how the printing process determines a microstructure within the steel that impacts the utility of the technology.
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Date Issued
2018
Identifier
CFE0007331, ucf:52144
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007331
Deposition Thickness Modeling and Parameter Identification for Spray Assisted Vacuum Filtration Process in Additive Manufacturing
Title
Deposition Thickness Modeling and Parameter Identification for Spray Assisted Vacuum Filtration Process in Additive Manufacturing.
Creator
Mark, August, Xu, Yunjun, Gou, Jihua, Lin, Kuo-Chi, University of Central Florida
Abstract / Description
To enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are often time deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties, the thickness of such nanocomposite layers must be precisely controlled. A thickness model of filter cakes created through a spray assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer...
Show moreTo enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are often time deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties, the thickness of such nanocomposite layers must be precisely controlled. A thickness model of filter cakes created through a spray assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer dynamics in the spray atomization and vacuum filtration are studied for the mass of solid particles and mass of water in differential areas, and then the thickness of a filter cake is derived. A two-loop nonlinear constrained optimization approach is used to identify the unknown parameters in the model. Experiments involving depositing carbon nanofibers in a sheet of paper are used to measure the ability of the model to mimic the filtration process.
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Date Issued
2015
Identifier
CFE0005974, ucf:50788
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005974
A Framework for Miniaturized Mechanical Characterization of Tensile, Creep, and Fatigue Properties of SLM Alloys
Title
A Framework for Miniaturized Mechanical Characterization of Tensile, Creep, and Fatigue Properties of SLM Alloys.
Creator
Torres-Caceres, Jonathan, Orlovskaya, Nina, Xu, Yunjun, Das, Tuhin, University of Central Florida
Abstract / Description
With the heightened design complexity that may be achieved through additive manufacturing (AM) comes an equally complex set of distinct material characteristics. To properly characterize new materials for use in selective laser melting (SLM), extensive analysis is necessary. Traditional testing techniques, however, can be prohibitive in time and cost incurred. The small punch test (SPT) has been developed for such purposes, where material is scarce or costly. Although lacking standardization,...
Show moreWith the heightened design complexity that may be achieved through additive manufacturing (AM) comes an equally complex set of distinct material characteristics. To properly characterize new materials for use in selective laser melting (SLM), extensive analysis is necessary. Traditional testing techniques, however, can be prohibitive in time and cost incurred. The small punch test (SPT) has been developed for such purposes, where material is scarce or costly. Although lacking standardization, SPT has been successfully employed with various materials to assess material properties such as the yield and ultimate strength and verified by traditional testing results. With the accompaniment of numerical simulations for use in the inverse method and determining correlation factors, several methods exist for equating SPT results with traditional results. There are, however, areas of weakness with SPT which require development, and the solution of the inverse method can be demanding of time and resources. Additionally, the combination of SPT and SLM is relatively unexplored in literature, though studies have shown that SPT is sensitive to the types of structures and unique material characteristics present in SLM components. The present research therefore focuses on developing a framework for characterizing SLM materials via the small punch test. Several types of SLM materials in various orientations and processing states are small punch tested to evaluate the ability of the SPT to track the effects of these as they cause the materials to evolve. A novel cyclic test method is proposed to fill the gap in SPT fatigue testing. Results from these tests are evaluated via numerical modelling using the inverse method solved with the least squares method. Samples were also inspected using digital microscopy to connect fracture morphology to processing parameter variations. A framework is thus presented with which SPT may be utilized to more economically and expeditiously characterize SLM materials.
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Date Issued
2018
Identifier
CFE0007109, ucf:51952
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007109
Characterization of SLM-Manufactured Turbine Blade Microfeatures from Superalloy Powders
Title
Characterization of SLM-Manufactured Turbine Blade Microfeatures from Superalloy Powders.
Creator
Ealy, Brandon, Kapat, Jayanta, Ahmed, Kareem, Vasu Sumathi, Subith, University of Central Florida
Abstract / Description
The limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel remains the material of choice for most hot gas path (HGP) components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings. Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental...
Show moreThe limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel remains the material of choice for most hot gas path (HGP) components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings. Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental performance gains responsible for increasing the allowable TIT have been made mainly through innovations in cooling technology, specifically convective cooling schemes. An emerging manufacturing technology may further facilitate the increase of allowable maximum TIT, thereby impacting cycle efficiencies. Laser Additive Manufacturing (LAM) is a promising manufacturing technology that uses lasers to selectively melt powders of metal in a layer-by-layer process to directly manufacture components, paving the way to produce designs that are not possible with conventional casting methods. This study investigates manufacturing qualities seen in LAM methods and its ability to successfully produce complex microfeatures in a mock turbine blade leading edge. Various cooling features are incorporated in design, consisting of internal impingement cooling, internal lattice structures, and external showerhead cooling. The internal structure is designed as a lattice of intersecting cylinders in order to mimic that of a porous material. Through a non-destructive approach, the presented design is analyzed against the departure of the design by utilizing X-ray computed tomography (CT). Employing this non-destructive testing (NDT) method, a more thorough analysis of the quality of manufacture is established by revealing the internal structures of the porous region and internal impingement array. Variance distribution between the design and manufactured test article are carried out for both internal impingement and external transpiration hole diameters from CT data. Flow testing is performed to characterize the uniformity of porous regions and flow behavior across the entire article for various pressure ratios. Discharge coefficients of internal impingement arrays and porous structures are quantified. A numerical model of fluid flow through the exact CAD geometry is analyzed over the range of experimental flowrates. By comparison of experimental and numerical data, performance discrepancies associated with manufacturing quality are observed. Simplifying assumptions to the domain are evaluated to compare predictions of CFD using the exact geometry. This study yields quantitative data on the build quality of the LAM process, providing more insight as to whether it is a viable option for manufacture of micro-features in current turbine blade production.
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Date Issued
2016
Identifier
CFE0006452, ucf:51428
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006452
Tensile-Compressive Asymmetry and Anisotropy of Fused Deposition Modeling PLA under Monotonic Conditions
Title
Tensile-Compressive Asymmetry and Anisotropy of Fused Deposition Modeling PLA under Monotonic Conditions.
Creator
Perkowski, Casey, Gordon, Ali, Kassab, Alain, Divo, Eduardo, University of Central Florida
Abstract / Description
Additive Manufacturing (AM) continues to gain popularity for its ability to produce complexly-shaped final use components that are impractical to manufacture by traditional methods; however, additive manufactured parts contain complex mesostructures that result in directionally-dependent mechanical properties that have yet to be fully characterized. This effort demonstrates a framework of experimental and analytical methods needed to characterize the uniaxial monotonic behavior of fused...
Show moreAdditive Manufacturing (AM) continues to gain popularity for its ability to produce complexly-shaped final use components that are impractical to manufacture by traditional methods; however, additive manufactured parts contain complex mesostructures that result in directionally-dependent mechanical properties that have yet to be fully characterized. This effort demonstrates a framework of experimental and analytical methods needed to characterize the uniaxial monotonic behavior of fused deposition modeling PLA using tensile and compressive experiments on specimens printed at various orientations. Based on experimental results, the asymmetry and anisotropy of the tensile and compressive response was analyzed for a candidate material. Specimens from different orientations underwent microscopy and failure surface analysis to correlate test data. The material was observed to exhibit tetragonal behavior with tensile-compressive asymmetry. The experimental and simulated results show a strong correlation. Based on the collection of results, analysis, and computations, this work demonstrates a practice that can be used to characterize similar materials for use in AM components.
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Date Issued
2017
Identifier
CFE0006778, ucf:51847
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006778
THE DESIGN AND DEVELOPMENT OF AN ADDITIVE FABRICATION PROCESS AND MATERIAL SELECTION TOOL
Title
THE DESIGN AND DEVELOPMENT OF AN ADDITIVE FABRICATION PROCESS AND MATERIAL SELECTION TOOL.
Creator
Palmer, Andrew, Elshennawy, Ahmad, University of Central Florida
Abstract / Description
In the Manufacturing Industry there is a subset of technologies referred to as Rapid Technologies which are those technologies that create the ability to compress the time to market for new products under development . Of this subset, Additive Fabrication (AF), or more commonly known as Rapid Prototyping (RP), acquires much attention due to its unique and futuristic approach to the production of physical parts directly from 3D CAD data, CT or MRI scans, or data from laser scanning systems by...
Show moreIn the Manufacturing Industry there is a subset of technologies referred to as Rapid Technologies which are those technologies that create the ability to compress the time to market for new products under development . Of this subset, Additive Fabrication (AF), or more commonly known as Rapid Prototyping (RP), acquires much attention due to its unique and futuristic approach to the production of physical parts directly from 3D CAD data, CT or MRI scans, or data from laser scanning systems by utilizing various techniques to consecutively generate cross-sectional layers of a given thickness upon the previous layer to form 3D objects. While Rapid Prototyping is the most common name for the production technology it is also referred to as Additive Manufacturing, Layer Based Manufacturing, Direct Digital Manufacturing, Free-Form Fabrication, and 3-Dimensional Printing. With over 35 manufacturers of Additive Fabrication equipment in 2006 , the selection of an AF process and material for a specific application can become a significant task, especially for those with little or no technical experience with the technology and to add to this challenge, many of the various processes have multiple material options to select from . This research was carried out in order to design and construct a system that would allow a person, regardless of their level of technical knowledge, to quickly and easily filter through the large number of Additive Fabrication processes and their associated materials in order to find the most appropriate processes and material options to create physical reproductions of any part. The selection methodology used in this paper is a collection of assumptions and rules taken from the author's viewpoint of how, in real world terms, the selection process generally takes place between a consumer and a service provider. The methodology uses those assumptions in conjunction with a set of expert based rules to direct the user to a best set of qualifying processes and materials suited for their application based on as many or as few input fields the user may be able to complete.
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Date Issued
2009
Identifier
CFE0002625, ucf:48241
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002625
EQUIBIAXIAL FLEXURAL STRENGTH TESTING OF ADVANCE CERAMICS
Title
EQUIBIAXIAL FLEXURAL STRENGTH TESTING OF ADVANCE CERAMICS.
Creator
Jordan, Ryan T, Orlovskaya, Nina, Kwok, Kawai; Ghosh, Ranajay, University of Central Florida
Abstract / Description
Ceramics are very important materials with many unique properties used in numerous industrial applications. Ceramics could be very hard and very strong in comparison to metals; however, they are very brittle, thus they are prone to instantaneous and catastrophic failure. Therefore, their reliability is compromised and it is very important to have advanced techniques that allow evaluating their mechanical behavior in many unusual stress states. One of such testing methods is biaxial strength...
Show moreCeramics are very important materials with many unique properties used in numerous industrial applications. Ceramics could be very hard and very strong in comparison to metals; however, they are very brittle, thus they are prone to instantaneous and catastrophic failure. Therefore, their reliability is compromised and it is very important to have advanced techniques that allow evaluating their mechanical behavior in many unusual stress states. One of such testing methods is biaxial strength method, that allows to measure properties not only unidirectional, but also in a biaxial way. The research work for this thesis will be built on design and development of ring-on-ring test jigs that will measure a biaxial strength of thin ceramic disks.
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Date Issued
2018
Identifier
CFH2000386, ucf:45700
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000386
Adiabatic Film Cooling Effectiveness of a Transpiration-Cooled Leading Edge Fabricated by Laser Additive Manufacturing
Title
Adiabatic Film Cooling Effectiveness of a Transpiration-Cooled Leading Edge Fabricated by Laser Additive Manufacturing.
Creator
Calderon, Luisana, Kapat, Jayanta, Raghavan, Seetha, Mingareev, Ilya, University of Central Florida
Abstract / Description
Laser additive manufacturing (LAM) is an emerging technology capable of fabricating complex geometries not possibly made by investment casting methods for gas turbine applications. LAM techniques consist of building parts in a layer-by-layer process by selectively melting metal powders. In the present study, a mock leading edge segment of a turbine blade fabricated by LAM of Inconel 718 powders is investigated. For this particular design, the traditional showerhead film cooling holes have...
Show moreLaser additive manufacturing (LAM) is an emerging technology capable of fabricating complex geometries not possibly made by investment casting methods for gas turbine applications. LAM techniques consist of building parts in a layer-by-layer process by selectively melting metal powders. In the present study, a mock leading edge segment of a turbine blade fabricated by LAM of Inconel 718 powders is investigated. For this particular design, the traditional showerhead film cooling holes have been replaced by two strips containing engineered-porous regions with the purpose of simulating the effect of transpiration cooling. Transpiration cooling has been considered a promising external convective cooling method capable of providing a more uniform film and higher adiabatic film cooling effectiveness than conventional discrete film cooling. In addition, many studies have shown that this technique can yield high firing temperatures with much less coolant consumption than discrete film cooling. In this current study, adiabatic film cooling effectiveness is investigated by means of mass transfer using pressure sensitive paint (PSP). The experiments are conducted for blowing ratios ranging between M = 0.03 and M = 0.28 for a nominal density ratio of 1.5. The density ratio is obtained by using air as the mainstream flow and CO2 as the secondary flow (or coolant source). Results indicate higher coverage and film cooling effectiveness when increasing blowing ratio at the expense of higher pressure drop. In addition, the experimental results are compared to numerical analyses performed using steady state Reynolds Average Navier Stokes (RANS) simulations.
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Date Issued
2018
Identifier
CFE0007315, ucf:52117
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007315
INVESTIGATION OF PS-PVD AND EB-PVD THERMAL BARRIER COATINGS OVER LIFETIME USING SYNCHROTRON X-RAY DIFFRACTION
Title
INVESTIGATION OF PS-PVD AND EB-PVD THERMAL BARRIER COATINGS OVER LIFETIME USING SYNCHROTRON X-RAY DIFFRACTION.
Creator
Northam, Matthew, Raghavan, Seetha, Ghosh, Ranajay, Vaidyanathan, Raj, University of Central Florida
Abstract / Description
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.
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Date Issued
2019
Identifier
CFE0007844, ucf:52830
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007844
Characterization of Anisotropic Mechanical Performance of As-Built Additively Manufactured Metals
Title
Characterization of Anisotropic Mechanical Performance of As-Built Additively Manufactured Metals.
Creator
Siddiqui, Sanna, Gordon, Ali, Raghavan, Seetha, Bai, Yuanli, Sohn, Yongho, University of Central Florida
Abstract / Description
Additive manufacturing (AM) technologies use a 3D Computer Aided Design (CAD) model to develop a component through a deposition and fusion layer process, allowing for rapid design and geometric flexibility of metal components, for use in the aerospace, energy and biomedical industries. Challenges exist with additive manufacturing that limits its replacement of conventional manufacturing techniques, most especially a comprehensive understanding of the anisotropic behavior of these materials...
Show moreAdditive manufacturing (AM) technologies use a 3D Computer Aided Design (CAD) model to develop a component through a deposition and fusion layer process, allowing for rapid design and geometric flexibility of metal components, for use in the aerospace, energy and biomedical industries. Challenges exist with additive manufacturing that limits its replacement of conventional manufacturing techniques, most especially a comprehensive understanding of the anisotropic behavior of these materials and how it is reflected in observed tensile, torsional and fatigue mechanical responses. As such, there is a need to understand how the build orientation of as-built additively manufactured metals, affects mechanical performance (e.g. monotonic and cyclic behavior, cyclically hardening/softening behavior, plasticity effects on fatigue life etc.); and to use constitutive modeling to both support experimental findings, and provide approximations of expected behavior (e.g. failure surfaces, monotonic and cyclic response, correlations between tensile and fatigue properties), for orientations and experiments not tested, due to the expensive cost associated with AM. A comprehensive framework has been developed to characterize the anisotropic behavior of as-built additively manufactured metals (i.e. Stainless Steel GP1 (SS GP1), similar in chemical composition to Stainless Steel 17-4PH), through a series of mechanical testing, microscopic evaluation and constitutive modeling, which were used to identify a reduced specimen size for characterizing these materials. An analysis of the torsional response of additively manufactured Inconel 718 has been performed to assess the impact of build orientation and as-built conditions on the shearing behavior of this material. Experimental results from DMLS SS GP1 and AM Inconel 718 from literature were used to constitutively model the material responses of these additively manufactured metals. Overall, this framework has been designed to serve as standard, from which build orientation selection can be used to meet specific desired industry requirements.
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Date Issued
2018
Identifier
CFE0007097, ucf:52883
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007097