Materials Science and Engineering Commons^™

Advancing Additive Manufacturing For Biomedical Applications: Antimicrobial And X-Ray Absorptive Composite Filaments For Fused Filament Fabrication, John M. Arnold Jr

University of New Orleans Theses and Dissertations

The objective of this research was to investigate the use of nano- and microparticle amendments for the creation of Poly-lactic Acid composite materials for use in biomedical applications using the Fused Filament Fabrication process of Additive Manufacturing. Composites were created with the goal of imparting the useful properties of antimicrobial activity and x-ray absorption to the material. In addition to testing the efficacy of the particle amendments in achieving the desired properties, the thermal and mechanical properties of the composite materials were tested to ensure that the composites would be compatible with the Fused Filament Fabrication process and would produce …

Investigating The Effect Of Bead Geometry On Fiber Orientation And Thermomechanical Properties For Large-Format Extrusion-Based Additive Manufacturing, Joanna F. Keaton

Electronic Theses and Dissertations

In large-format extrusion-based additive manufacturing of polymer composites, the relationship between material properties and processing parameters requires further investigation. This thesis focuses on the relationship between fiber orientation and thermomechanical properties for short fiber-filled thermoplastic polymer systems manufactured by extrusion-based additive manufacturing. Fiber orientation is particularly important in determining the thermomechanical properties of the composite material as properties in the direction of deposition are expected to be higher for highly aligned fibers than randomly aligned fibers. Fiber orientation distribution, which is related to processing parameters and deposition conditions, can be efficiently represented by the orientation tensor. The orientation tensor can …

Mechanical Characterization Of Automated Fiber Placement And Additive Manufacturing Hybrid Composites, Lucan Haviland

Electronic Theses and Dissertations

This thesis presents the optimization of processing parameters based on the mechanical properties of Continuous Fiber-Reinforced Thermoplastic (CFRTP) Unidirectional (UD) consolidated tapes. The UD tapes were consolidated using an AFP head and a thermoforming press for comparison. The adhesive strength of hybrid parts consisting of CFRTP UD tape bonded to a 3D-printed substrate with the same matrix system were investigated. Large Area Additive Manufacturing (LAAM) was utilized for the 3D-printed parts. Different types of thermoplastic composite materials were explored, including Glass Fiber reinforced Polyethylene Terephthalate Glycol (GF/PETG), Carbon Fiber reinforced Polyethylene Terephthalate Glycol (CF/PETG), Carbon Fiber reinforced Polycarbonate (CF/PC), and …

Additive Manufacturing Of High-Performance Nanolamellar Eutectic High-Entropy Alloys, Jie Ren

Doctoral Dissertations

Additive manufacturing, also called three-dimensional (3D) printing, is an emerging technology for printing net-shaped components layer by layer for applications in automotive, aerospace, biomedical and other industries. In addition to the vast design freedom offered by this approach, metal 3D printing via laser powder-bed fusion (L-PBF) involves large temperature gradients and rapid cooling and provides exciting opportunities for producing microstructures and mechanical properties beyond those achievable by conventional processing routes. Although these extreme printing conditions enable microstructural refinement to the nanoscale for achieving high strength. However, high-strength nanostructured alloys by laser additive manufacturing often suffer from limited ductility. Eutectic high-entropy …

Fatigue And Fracture Of Electron Beam Melting Ti-6al-4v, William A. Grell

Electronic Theses and Dissertations

For applications in the aerospace field, selection of materials for a given design requires an understanding of critical properties, like fatigue and fracture, in addition to static mechanical and physical properties. With the ongoing advancements in metallic additive manufacturing techniques and the interest in applying the process to aerospace applications, there is a clear need to fully characterize properties. Arguably, the most attractive alloy for applications in aerospace is the Ti-6Al-4V alloy. The current dissertation examines the mechanical properties of the alloy, made by the Electron Beam Melting (EBM) Powder Bed Fusion (PBF) method. As illustrated in this work, the …

Correlating Large-Format Additive Manufacturing Processing Parameters To Fiber Length And The Mechanical Performance Of Reinforced Polymer Composites, Andrew Phillip Rhodes

Masters Theses

The Big Area Additive Manufacturing (BAAM) system at Oak Ridge National Laboratory has been used to produce carbon fiber reinforced structures for several years, including vehicles, building constituents, composite tooling, etc. While the development of a large-format polymer additive manufacturing (AM) system has moved quickly, the impact of the BAAM’s extruder on the length of carbon fiber feedstock has not been systematically studied. Numerous studies in processing fiber reinforced thermoplastics in plasticizing and injection molding systems have shown that fibers are subjected to significant shear as they are processed, which can cause a drastic reduction in fiber length which negatively …

Multimaterial, Core-Shell Direct Ink Writing Of Flexible Strain Sensors For Pneumatically-Actuated Soft Robotic Hinge Joints, John Michael Burke

Graduate Theses, Dissertations, and Problem Reports

Direct ink writing (DIW) provides for an expansive material library and the ability to print multiple materials with tailored functionalities in a controllable and single-step process. Particularly beneficial is the net shape printing under ambient conditions of a wide range of materials normally incompatible with one another. Coaxial DIW is a 3D printing technique that allows for two dissimilar inks to be extruded simultaneously in a co-flow manner. In this work, custom-designed coaxial nozzles were 3D-printed using a stereolithography printer. Composite inks comprised of thermoplastic polyurethane and silver were developed and studied. The coaxial nozzles were then used to co-extrude …

Enhanced Performance Of 3d Electroactive Polymer Transducers Via Hierarchical Structures, Frederick B. Holness

Electronic Thesis and Dissertation Repository

Conjugated polymers (CPs) are a class of polymers that exhibit a change in size or shape in response to electrical stimuli. The unique combination of electrical and mechanical properties facilitates the fabrication of novel devices in a broad range of applications including: sensors, actuators, and lab-on-a-chip systems. The alternating single and double bonds along the polymer chain of CPs enables their electroactive properties but is also responsible for processability associated with CPs that has limited fabrication methods. Recently a photosensitive CP composite enabling additive manufacturing (AM) of 3D CP structures was developed. However, the introduction of a copolymer for mechanical …

A Study On Early Age Properties Of Concrete For Precast And 3d Printing, Debalina Ghosh

Doctoral Dissertations

Concrete is the second-most consumed material, leading the global Portland cement production of 4.1 billion tons in 2020 and 5-8% of global Carbon dioxide (CO₂) emission annually. As with any other material and practice, the construction industry is also ever-changing to meet market demand, evolving technology, and resource limitation. In the case of concrete construction, one of the main concerns is the lack of automation. In the last few decades, some new construction methods have risen to address this concern. Some of these economic and successful practices are precast construction, self-compacting concrete (SCC), and 3D printing of concrete(3DPC). …

Optimized 3d-Printing Of Carbon Fiber-Reinforced Polyether-Ether-Ketone (Cfr-Peek) For Use In Overmolded Lattice Composite, Ryan C. Ogle

Masters Theses

Current orthopedic implants are overwhelmingly composed from metallic materials. These implants show superior mechanical properties, but this can additionally result in stress shielding due to a modulus mismatch between the bone tissue and implanted device. Polymeric implants reduce this stress shielding effect but have much lower mechanical properties, limiting their use. Polylactic acid (PLA) is a widely used biodegradable thermoplastic polymer, however, its use has been limited by the polymer’s mechanical properties and rapid loss of strength during degradation in vivo. Polyether-ether-ketone (PEEK) is another common biocompatible polymer , with chemical and mechanical properties which make it a popular alternative …

Characterization Of Materials Properties In Additively Manufactured Aisi-420 Martensitic Steel Deposited By Laser Engineered Net Shaping, Md Mehadi Hassan

Nanoscience and Microsystems ETDs

Metal additive manufacturing (AM) is a disruptive technology enabling the fabrication of complex and near-net-shaped parts by adding material layer-wise. It offers reduced lead production time. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical, and mold tooling. Despite the tremendous advantages of AM, some challenges still prevent this technology's adoption in high-standard applications. Anisotropy and inhomogeneity in the mechanical properties of the as-built parts and the existence of pores and lack-of-fusion defects are considered the main issues in directed energy deposition (L-DED) parts. Laser-engineered net shaping LENS® offers excellent possibilities to fabricate metal tools …

Enabling Nanoimprint Lithography Techniques Across Multiple Manufacturing Processes, Vincent Einck

Doctoral Dissertations

Advanced nanooptics in the areas of flat lenses, diffractive elements, and tunable emissivity require a route to high throughput manufacturing. Nanooptics are often demanding of high refractive index materials, nanometer precision and ease of fabrication. Nanoimprint lithography (NIL) is a low-cost, high throughput manufacturing technique beginning to be realized in commercial industry.^1,2 The NIL process is an ideal manufacturing candidate due to its ability to have a fast process time, efficient use of materials, repeatability and high precision while also having wide diversity of potential structures and material choices. Appling NIL techniques to other facets of manufacturing enable the …

Mechanical Properties And Tension-Tension Fatigue Behavior Of A Novel Additively Manufactured Polymer Matrix Composite At Room And Elevated Temperature, Grayson M. Harber

Theses and Dissertations

The tension-tension fatigue behavior of a novel additively manufactured AM carbon fiber reinforced polymer matrix composite was studied. This novel material system consists of T1100 carbon fibers, and a UV photocured resin developed by Continuous Composites and Sartomer. Tensile properties and tension-tension fatigue were investigated for the 090 fiber orientation as well as for the ±45 fiber orientation. Specimens with 0/90 fiber orientation were tested at ambient laboratory temperature 23 °C and at elevated temperature 150 °C, while the specimens with the ±45 fiber orientation were tested only at ambient laboratory temperature. Tension-tension fatigue testing was carried out with a …

Ferrous Alloy Manufacturing For The Martian Surface Through In-Situ Resource Utilization With Ionic Liquids Harvested Iron And Bosch Process Carbon, Blake C. Stewart

Theses and Dissertations

As research continues for the habitation of the Lunar and Martian surfaces, the need for materials for construction of structural parts, mechanical components, and tools remains as a major milestone. The use of in-situ resource utilization (ISRU) techniques is critical due to the financial, physical, and logistical burdens of sending supplies beyond low-Earth orbit. The Bosch process is currently in development as a life support system at the National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) to regenerate oxygen (O2) from metabolic carbon dioxide (CO2) with the byproduct of elemental carbon (C). The Bosch process presents a …

Fundamental Understanding Of The Transient Melt Pool Dynamics, Solidification Kinetics And Build Texture In Spot-Melt Additive Manufacturing Of Ti-6al-4v, Rakesh Rajaram Kamath

Doctoral Dissertations

The overarching goal of this dissertation is to better understand the underlying process-structure relationships in play during the implementation of a spot melt strategy for metal additive manufacturing, which has become a popular alternative to the conventional raster melt strategy for site-specific microstructure control. In the first part of this dissertation, the effect of a spot melt strategy on the solidification texture, variant selection, phase fraction, and their variations along the build height of an E-PBF Ti-6Al-4V is investigated in comparison to a conventional linear melt strategy using high-energy synchrotron x-ray diffraction. In spite of the thermal excursions involved, the …

Additive Manufacturing Of Sub-Micron Features And Mechanical Linkages, David K. Limberg

Doctoral Dissertations

In recent years material constraints have become the limiting factor in several fields, including batteries, robotics, and medicine, and these needs have prompted the development of materials with programmable properties. To this end, much effort has been dedicated to designing metamaterials that have unprecedented optical, mechanical, and thermal properties, along with systems for additive manufacturing to build their complex structures with high precision and throughput. The field of additive manufacturing has proved to be a platform for innovation across many industries yet is still limited with regards to feature sizes, print rates, and diversity of materials. Mechanical devices like linkages …

On The Effects Of Additive Manufacturing Process Parameters On The Performance Of Hastelloy-X: A Neutron Diffraction Experiment And Crystal Plasticity Finite Element Model, Ahmed Aburakhia

Electronic Thesis and Dissertation Repository

Additive manufacturing (AM) is increasingly becoming one of the favourable manufacturing techniques in various industries, such as transportation and energy. The reason for the extensive use of AM lies in the ability to use a wide range of process parameters for manufacturing engineering parts with complex geometries that cannot be effectively manufactured using traditional methods such as casting or forging. Understanding the role of process parameters is crucial for developing predictive models, as well as for manufacturing engineering components with the desired properties.

This research aims to characterize the influence of AM process parameters on the deformation mechanisms of Hastelloy-X, …

Additive Manufacturing Of Variable Contrast Computed Tomography Anatomical Phantoms Using A Single Feedstock In Fused Filament Fabrication, Cory J. Darling

University of New Orleans Theses and Dissertations

Anatomical phantoms used in biomedical education and training benefit greatly from Fused filament fabrication’s (FFF) ability to rapidly produce complex and unique models. Current materials and methods used in FFF have limited ability to accurately produce phantoms that can mimic the radiological properties of multiple biological tissues. This research demonstrates that the CT contrast of FFF produced models can be modified by varying the concentration of bismuth oxide in acrylonitrile butadiene styrene (ABS) filaments and a tunable CT contrast that mimics the CT contrast ranging from fatty tissue to cortical bone using a single composite filament without introducing artificial image …

Effects Of Sizing Agents On Mechanical Properties Of Carbon Fiber–Polymer Composites Via Fused Filament Fabrication Additive Manufacturing., Benjamin D. Mitchell

Electronic Theses and Dissertations

This study demonstrated the effects of changing the sizing agent parameter during the preparation of carbon fibers on the mechanical properties of composite made with acrylonitrile butadiene styrene (ABS) as the matrix material and carbon fibers as the fiber material. Three types of sizing agents produced by Allnex were used to coat three different batches of carbon fibers that were mixed with a torque rheometer and extruded with a barrel-style melt extruder into continuous spools of 1.75 mm filament for use with commercial 3D printers. Tensile tests were conducted on the filaments and tensile bars printed from the materials. Results …

Additive Manufacturing Of Sensors For Extreme Environments, Kiyo Tiffany Fujimoto

Boise State University Theses and Dissertations

Advanced manufacturing based direct-write technologies have emerged as the predominant enabler for the fabrication of active and passive sensors for use in harsh operating environments. The ability to directly write and integrate electronic components onto physical packaging can be achieved with additive manufacturing (AM) methods such as direct write technologies (DWT) which include aerosol jet printing (AJP), Ink Jet Printing (IJP), Plasma Jet Printing (PJP), and Micro-Dispense Printing (MDP). In this work, we investigate the use of these methods to accelerate, modernize, and enhance the functionality of sensors and instrumentation to achieve the goal of improving the safety and efficiency …

Potential Solution To Meet Growing Demands Of Refractory Metal: Selective Laser Melting Of Molybdenum-Tungsten Alloy, Jae Yu

Theses and Dissertations

Selective laser melting (SLM) of refractory metals has been of high interest in research due to the metals’ potential desirable characteristics in aeronautical and space applications. In particular, molybdenum and tungsten have been the focus of several studies in the search for high temperature and high strength purposes in applications like supersonic aircraft, re-entry vehicles, nuclear fission, power generation, and other space systems. However, there is still a significant knowledge gap to process defect-free alloys and making use of them in practical engineering functions. The aim of this study is to characterize the relationship between the microstructure and mechanical properties …

Processing To Enable Direct-Write Additive Manufacturing Of Ceramics And Ceramic Composites, Austin Martin

Doctoral Dissertations

"This research focuses on the processing of novel feedstocks for and during direct-write additive manufacturing (AM), specifically the direct ink writing (DIW) and Ceramic On-Demand Extrusion (CODE) manufacturing processes, in order to produce ceramic and ceramic-based composite components. Strongly dispersed, concentrated (φ = 0.42), nanoparticle (d₅₀ ~0.3 µm), zirconia (ZrO₂) pastes were used to print densely filled, large continuous volume (≳ 1 cm³) ceramic components. An elastic shear modulus (G’) of 56,000 Pa and yield stresses between 6 and 10 Pa allowed for printed components of 34.5 mm in height over 115 layers without slumping …

Functionally Magnetic Gradient Copper-Nickel Material Fabricated Via Directed Energy Deposition, Vy Tran Phuong Nguyen

Graduate Theses, Dissertations, and Problem Reports

Functionally gradient materials (FGMs) of CuSn10 and Inconel 718 were fabricated via a hybrid directed energy deposition (DED) system. The objective of the present thesis is to determine the feasibility of manufacturing CuSn10 and Inconel 718 FGMs via DED and investigate the physical and mechanical properties and the microstructures of the resulting FGMs. The physical tests comprised of conductivity and Seebeck coefficient measurements. The microstructure analysis and mechanical testing include microscopic imaging, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and hardness test. In addition, compressive strength test was performed to analyze the interface bonding behaviors.

Additive Manufacturing Waste Management System - Plastic Extrusion Process, Gabriel Bennett, Lindsay Liebrecht, David Lyogky, Wilson Woods

Williams Honors College, Honors Research Projects

3D printing is a fast-growing market with its main source of waste being PLA and ABS plastics. In 2019, the global additive manufacturing market grew to over $10.4 billion, crossing the pivotal double-digit billion threshold for the first time in its nearly 40-year history. (SmarTech Analysis, 2020 Additive Manufacturing Market Outlook and Summary of Opportunities Report). The waste is generated from failed prints and rejected support structures which are common occurrences for personal use. Plastic recycling has become one of the leading discussions of environmental protection and waste management. The 3D market currently does not offer an effective and affordable …

Thermal And Mechanical Numerical Modeling Of Extrusion-Based 3d Printed Reinforced Polymers For Selecting Manufacturing Process Parameters, Sunil Bhandari

Electronic Theses and Dissertations

Extrusion-based 3D printing of thermoplastic polymer composites manufactures parts that have nonhomogenous, orthotropic, and process-dependent macro-scale material properties. As a part of the dissertation, research works were carried out to: • improve the interlayer mechanical properties and reduce the orthotropy, • use experimentally homogenized orthotropic material properties to numerically model the mechanical behavior of the non-homogenous orthotropic 3D printed parts, • create an efficient numerical thermal model to predict the process-dependent thermal history of the 3D printed part, and • aid the manufacturing process by selecting a suitable set of processing parameters based on a simplified sequentially coupled thermomechanical model. …

Structural Stability Of Thermosets During Material Extrusion Additive Manufacturing, Stian K. Romberg

Doctoral Dissertations

Over the past decade, the scale of polymer additive manufacturing has been revolutionized with machines that print massive thermoplastic parts with greater geometric complexity than can be achieved by traditional manufacturing methods. However, the heat required to print thermoplastics consumes energy and induces thermal gradients that can reduce manufacturing flexibility and final mechanical properties. With the ability to be extruded at room temperature and excellent compatibility with fibers and fillers, thermoset resins show promise to decrease the energy consumption, expand the manufacturing flexibility, and broaden the material palette offered by large-scale polymer additive manufacturing. However, structural instability in the uncured …

Optimization Of 3d Printed Mold Performance For Injection Molding Via Hollow Infill Patterns, Alan Fong

University Honors Theses

The applicability of hollow infill patterns has been explored for its applications in making 3D printed polymer-based injection molds in the additive manufacturing industry. Hollow infill patterns offer a significant reduction in material costs as well as the opportunity for reducing the cooling times via pumping a coolant fluid through the hollow cavity in a similar fashion to traditional conformal cooling channels. A 3D Jacks Support Hollow mold model was determined to be the best performing design. FEA analysis was conducted to determine the maximum reduction in internal volume (percentage of material saved) that could be achieved without exceeding the …

3d Printing Of Hybrid Architectures Via Core-Shell Material Extrusion Additive Manufacturing, Robert Cody Pack

Doctoral Dissertations

Biological materials often employ hybrid architectures, such as the core-shell motif present in porcupine quills and plant stems, to achieve unique properties and performance. Drawing inspiration from these natural materials, a new method to fabricate lightweight and stiff core-shell architected filaments is reported. Specifically, a core-shell printhead conducive to printing highly loaded fiber-filled inks, as well as a new low-density syntactic foam ink, are utilized to 3D-print core-shell architectures consisting of a syntactic epoxy foam core surrounded by a stiff carbon fiber-reinforced epoxy composite shell. Effective printing of test specimens and structures with controlled geometry, composition, and architecture is demonstrated …

Process-Structure-Property Relationships In 3d-Printed Epoxy Composites Produced Via Material Extrusion Additive Manufacturing, Nadim S. Hmeidat

Doctoral Dissertations

Extrusion-based additive manufacturing (AM) technologies, such as direct ink writing (DIW), offer unique opportunities to create composite materials and novel multi-material architectures that are not feasible using other AM technologies. DIW is a novel 3D-printing approach in which viscoelastic inks, with favorable rheological properties, are extruded through fine nozzles and patterned in a filament form at room temperature.

Recent developments in DIW of polymer composites have led to expanding the range of materials used for printing, as well as introducing novel deposition strategies to control filler orientation and create improved functional/structural composite materials. Despite these substantial advancements, the successful and …

Quality Assurance Of Lightweight Structures Via Phase-Based Motion Estimation, Ikenna E. Ifekaonwu

Electronic Theses and Dissertations

In recent years, lightweight structures have become mature and adopted in various applications. The importance of quality assurance cannot be overemphasized hence extensive research has been conducted to assess the quality of lightweight structures. This study investigates a novel process that exploits motion magnification to investigate the damage characteristics of lightweight mission-critical parts. The goal is to assure the structural integrity of 3D printed structures and composite structures by determining the inherent defects present in the part by exploiting their vibration characteristics. The minuscule vibration of the structure was recorded with the aid of a high-speed digital camera, and the …