Mechanical Engineering Commons^™

High-Throughput Tensile Testing Reveals Stochastic Properties In Additively Manufactured Steel, Bradley C. Salzbrenner

Mechanical Engineering ETDs

An adage within the Additive Manufacturing (AM) community is that “complexity is free”. Complicated geometric features that normally drive manufacturing cost and limit design options are not typically problematic in AM. While geometric complexity is usually viewed from the perspective of part design, this advantage of AM also opens up new options in rapid, efficient material property evaluation and qualification. This Thesis demonstrates how 100’s of miniature tensile bars can be produced and tested for comparable cost and in comparable time to a few conventional tensile bars. With this technique, it is possible to evaluate the stochastic nature of mechanical …

Alternative Method For Posterior Lumbar Discectomy And Development Of Associated Bench Top Test, Alfred Levinson, Parth Patel, Rahul Peddi, Sarah Peters, Jon Willard

Capstone Design Expo Posters

A discectomy is a common surgical procedure performed to remove the fibrous disc material between adjacent vertebrae in the spine, known as vertebral disc. Current methods and tools used in discectomies are time consuming and potentially dangerous, with opportunity for human error. There is a need for a new method of disc removal that can improve clinical results by reducing surgical times, preventing damage to surrounding anatomy, and more thoroughly removing the vertebral disc. A reduction in surgery times and increase of effective disc removal will help to increase success, recovery, and spinal fusion rates. This project aims to provide …

Low Velocity Impact And Rf Response Of 3d Printed Heterogeneous Structures, Sandeep Keerthi

Browse all Theses and Dissertations

Three-dimensional (3D) printing, a form of Additive manufacturing (AM), is currently being explored to design materials or structures with required Electro-Mechanical-Physical properties. Microstrip patch antennas with a tunable radio-frequency (RF) response are a great candidate for 3D printing process. Due to the nature of extrusion based layered fabrication; the processed parts are of three-layer construction having inherent heterogeneity that affects structural and functional response. The purpose of this study is to identify the relationship between the anisotropy in dielectric properties of AM fabricated acrylonitrile butadiene styrene (ABS) substrates in the RF domain and resonant frequencies of associated patch antennas and …

Design And Testing Of Scalable 3d-Printed Cellular Structures Optimized For Energy Absorption, Sagar Dilip Sangle

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Sandwich panel structures are widely used due to their high compressive and flexural stiffness and strength-to-weight ratios, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures that are often based upon honeycomb topologies. Interest in additive manufacturing (AM), popularly known as 3D printing (3DP), has rapidly grown in past few years. The 3DP method is a layer-by-layer approach for the fabrication of 3D objects. Hence, it is very easy to fabricate complex structures with complex internal features that cannot be manufactured by any other fabrication processes. Due to the …

On-Orbit Autonomous Repair: Systems Design And Project Management Of The Orbital Factory Ii Cube-Satellite, Mike Louis Everett

Open Access Theses & Dissertations

In 2016, a group of faculty, staff and students from the University of Texas at El Paso submitted a formal entry to the ULA CubeCorp competition to launch a 1U Cube Satellite into Orbit. In September of 2016, the team was awarded a launch opportunity to a prestigious GTO orbit to test and validate electrically conductive printing on within the Van Allen Radiation belts. This Dissertation is focused upon the management plan and specific decision that were implemented to accomplish this goal within a one year time frame and on a conservative budget.

In 2018 this satellite will launch aboard …

Design And Development Of A Foil Application Tool For A Foil Embedding Process In The Multi3d Manufacturing System, Betty Elizabeth Mckenzie

Open Access Theses & Dissertations

Additive manufacturing (AM) encompasses different technologies, including material extrusion 3D printing, a technology commonly referred to as fused deposition modeling (FDM), which is the focus of the work described in this manuscript. Additive manufacturing is a growing technology with many applications in numerous fields from the air force to medical offices. FDM is a process that uses thermoplastics, in this case polycarbonate (PC), where the PC is heated and selectively dispensed in a layer-by-layer process to create a 3D printed part. Currently, FDM systems have advantages over subtractive manufacturing or machining because cavities and other components (e.g., microchips, valves, and …

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical and Aerospace Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

Error Mapping Of Build Volume In Selective Laser Melting, Ninad Kulkarni

Masters Theses

“Selective laser melting is one of the commonly used additive manufacturing processes employed for production of functional part. Therefore, quality aspects such as dimensional accuracy have become a point of great interest. Like all of the other additive manufacturing processes selective laser melting process suffers from the issue if having wide range of process parameters making the process control a complex task. Additionally, issues specific to the selective laser melting process such as position dependency of accuracy of the part, makes it difficult to predict the resulting dimensional inconsistencies in the part manufactured by this processes. This research is an …

Design Optimization For Heat Dissipation In Polymer Additive Manufacturing With Joule Heating, Tania Alejandra Ventura

Open Access Theses & Dissertations

Nowadays, the use of additive manufacturing (AM) is mainly focused on the production of prototypes with the purpose of evaluating a design. This industry has become a subject of constant reinvention; in fact, an emerging application of AM is focused on creating parts with embedded electronics. However, the development of both traditional and additive manufactured electronics has led to an increase in power densities and size reduction. Consequently, thermal management has become essential in electronics, as overheating decreases reliability of the component leading to a premature failure.

In this study, a polycarbonate component design with integral electrical circuitry that is …

Comprehensive Finite Element Modeling Of Ti-6al-4v Cellular Solids Fabricated By Electron Beam Melting, Edel Arrieta

Open Access Theses & Dissertations

Additive manufacturing permits the fabrication of cellular metals which are materials that can be highly customizable and possess multiple and extraordinary properties such as damage tolerance, metamorphic and auxetic behaviors, and high specific stiffness. This makes them the subject of interest for innovative applications. With interest in these materials for energy absorption applications, this work presents the development of nonlinear finite element models in commercial software platforms (MSC Patran/Nastran) that permit the analysis of the deformation mechanisms of these materials under compressive loads. In the development of these models, a detailed multiscale study on the different factors affecting the response …

Low-Velocity Impact Behavior Of Sandwich Panels With 3d Printed Polymer Core Structures, Andrew Joseph Turner

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Sandwich panel structures are widely used in aerospace, marine, and automotive applications because of their high flexural stiffness, strength-to-weight ratio, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures, which are often based upon honeycomb topologies. The recent progress of additive manufacturing (AM) (popularly known as 3D printing) processes has allowed lattice configurations to be designed with improved thermal-mechanical properties. The aim of this work is to design and print lattice truss structures (LTS) keeping in mind the flexible nature of AM. Several 3D printed core structures were created …

Resilience And Toughness Behavior Of 3d-Printed Polymer Lattice Structures: Testing And Modeling, Mohammed Al Rifaie

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This research focuses on the energy absorption capability of additively manufactured or 3D printed polymer lattice structures of different configurations. The Body Centered Cubic (BCC) lattice structure is currently being investigated by researchers for energy absorption applications. For this thesis, the BCC structure is modified by adding vertical bars in different arrangements to create three additional configurations. Four designs or sets of the lattice structure are selected for comparison including BCC, BCC with vertical bars added to all nodes (BCCV), BCC with vertical bars added to alternate nodes (BCCA), and BCC with gradient arrangements of vertical bars (BCCG). Both experimental …

Additive Manufacturing Of Glass Using A Filament Fed Process, Junjie Luo

Doctoral Dissertations

"There are many scientific and engineering applications of glass including optics, communications, electronics, and hermetic seals, there has been minimal research towards the Additive Manufacturing (AM) of transparent glass parts. The special thermal and optical properties of glasses make them hard to be printed using conventional AM techniques. In this dissertation, two different AM techniques for glass AM were developed, Selective Laser Melting (SLM) and filament fed process.

Semi-transparent parts were printed with SLM process. However, the filament fed process was found to be more robust and promising for printing optically transparent glass parts. Therefore, this dissertation is focused on …

Selective Resistive Sintering: A Novel Additive Manufacturing Process, Austin Bryan Van Horn

Graduate Theses and Dissertations

Selective laser sintering (SLS) is one of the most popular 3D printing methods that uses a laser to pattern energy and selectively sinter powder particles to build 3D geometries. However, this printing method is plagued by slow printing speeds, high power consumption, difficulty to scale, and high overhead expense. In this research, a new 3D printing method is proposed to overcome these limitations of SLS. Instead of using a laser to pattern energy, this new method, termed selective resistive sintering (SRS), uses an array of microheaters to pattern heat for selectively sintering materials. Using microheaters offers significant power savings, significantly …

Revolutionized Additive Manufacturing, Matthew Walker, Winthrop Townsend, Luca Fuller

Mechanical Engineering

No abstract provided.

Non-Destructive Evaluation Of Functional Material Properties Performed On Additively Manufactured Coupons, Devin S. Plagge

Mechanical Engineering ETDs

This thesis presents the development of non-destructive characterization of functional material properties of additively manufactured metals. In particular, this study was focused on the common structural stainless steel alloy, 316L, utilizing a coupon designed specifically for simple modal analysis. Additive manufacturing (AM) has moved to the forefront of the manufacturing world, particularly in aerospace and defense segments because of the potential to produce multi-functional, highly optimized components. The ability to confidently qualify these complex, and thus expensive, components has been lagging behind the advancing technology. The adoption of traditional characterization techniques developed for wrought materials has been most common, and …

Fiber Length Attrition In Additive Manufacturing, Michael Chapiro

Materials Engineering

Chopped carbon fibers are used as reinforcements in thermoplastics, but the viscous shear forces that arise in melt-processing reduces the fiber length well below its critical length resulting in only moderate strength and stiffness gains compared to the neat resin. This research project aimed to experimentally determine the effect of the melt–flow portion of a single-screw- extrusion process on carbon fiber length attrition in isolation from the immediately preceding screw–plastication step that is responsible for most of the heat needed for melting. Carbon fibers with an initial length of 2 mm were stirred into 5,000 centipoise and 10,000 centipoise silicone …

Metals Am Design For Manufacturing, Maren Cosens, Ben Wong, Kevin Hale

Mechanical Engineering

We are looking to improve upon the current post processing techniques for metal additive manufacturing (AM). This project, sponsored by Lawrence Livermore National Laboratory (LLNL), will investigate ways to improve the design of stainless steel 316 parts made by AM, and how these designs will help with post processing techniques. We hope that the findings regarding stainless steel will apply to to improve the AM and post processing handshake in general. In particular, the project will focus on including different features in different basic part design shapes to aid in fixturing and post-processing of the part made by AM. This …

Metals Additive Manufacturing Powder Aging Characterization, Thomas Russell Lovejoy, Nicholas Karl Muetterties, David Takeo Otsu

Mechanical Engineering

The metallic additive manufacturing process known as selective laser melting requires highly spherical, normally distributed powder with diameters in the range of 10 to 50 microns. Previous observations have shown a degradation in powder quality over time, resulting in unwanted characteristics in the final printed parts. 21-6-9 stainless steel powder was used to fabricate test parts, with leftover powder recycled back into the machine. Powder samples and test specimens were characterized to observe changes across build cycles. Few changes were observed in the physical and mechanical properties of the specimens, however, there were indications of chemical changes across cycles. Potential …

Measuring Accuracy Of Two 3d Printing Materials, Mudassir Ali

Master of Technology Management Plan II Graduate Projects

Part accuracy is one of the important aspect in the manufacturing industry. The overall inaccuracy of the parts being built by RP technology has been one of the major challenges that need to be overcome. Though all the printing materials come with specifications, but the suppliers and manufactures does not specify the accuracy of the materials. In this study we established a study which compares the accuracy of the materials in consideration and performed an experiment to establish the superiority of a material in terms of accuracy over each other. The purpose of this project was to compare the dimensional …

Feasibility Of Attaining Fully Equiaxed Microstructure Through Process Variable Control For Additive Manufacturing Of Ti-6al-4v, Sarah Louise Kuntz

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One of the greatest challenges in additive manufacturing is fabricating titanium structures with consistent and desirable microstructure. To date, fully columnar deposits have been achieved through direct control of process variables. However, the introduction of external factors appears necessary to achieve fully equiaxed grain morphology using existing commercial processes. This work introduces and employs an analytic model to relate process variables to solidification thermal conditions and expected beta grain morphology at the surface of and at the deepest point in the melt pool. The latter is required in order to ensure the deposited microstructure is maintained even after the deposition …

Characterization Of Performance Of A 3d Printed Stirling Engine Through Analysis And Test, Julie Vodhanel

ETD Archive

This thesis involves the fusion of two technologies, Stirling engines and additive
manufacturing. The project began by building a Stirling engine primarily out of 3D printed parts. Methods to measure the power output were designed and built with a combination of 3D printed and off the shelf parts. The Stirling engine was tested to see if there was a correlation to analysis results, and a regenerator was installed to determine the effect on performance for this relatively low temperature engine. Finally, variations in test operation and the use of heat sinks were used to find a combination that will allow …

Creating Multi-Functional G-Code For Multi-Process Additive Manufacturing, Efrain Aguilera Jr

Open Access Theses & Dissertations

Additive manufacturing (AM) started over thirty years ago and with it a manufacturing revolution that moves industrial production into the personal home. With recent interest shifting into multi-functional parts fabricated through AM technologies, unified systems are being developed. Merging different manufacturing technologies into one single machine is a challenge but undergoing research has shown promise in the development of multi-functional systems. Concurrent work is being done in the software, automation, and hardware aspect of multi-functional systems. An effort to use industry compatible Computer Aided Design (CAD) software to design multi-functional parts including circuits, micro-machining, and foil embedding then exporting and …

Effect Of Build Parameters On Mechanical Properties Of Ultem 9085 Parts By Fused Deposition Modeling, Krishna Prasanth Motaparti

Masters Theses

"Additive manufacturing is a fabrication technique that is used to build components by depositing material in a layer-by-layer manner. Fused Deposition Modeling (FDM) is one of the additive manufacturing techniques which is widely used for prototyping and production applications of thermoplastic components. In load bearing applications, the flexural and compression forces often coexist. In order to avoid failure under these loads, it is essential to study the mechanical properties of the components fabricated by FDM. The main focus of this research is to study the mechanical properties of the fabricated components and to comprehend their dependence on various build parameters. …

Development Of The Thermal Wire Embedding Technology For Electronic And Mechanical Applications On Fdm-Printed Parts, Daniel Abraham Marquez

Open Access Theses & Dissertations

Additive Manufacturing (AM) has increased in popularity and attracted much attention from many fields such as automotive, aviation, aerospace, and even the fashion industry. Since the early 2000s, Fused Deposition Modeling (FDM) technologies have been the most popular in the AM world ("Wohlers Talk" Popularity of FDM). These technologies have been mainly used for building parts for prototype and structural type of applications such as a fixture for components or a housing for mechanisms.

With the current state of the FDM technologies, the functionality of the parts that are printed are limited to the applications listed before or simply just …

Modeling And Characterization Of Piezoelectric Based Multifunctional Structures, Ricardo Martinez Hernandez

Open Access Theses & Dissertations

Continuous monitoring of high pressure and high temperature in energy system applications has been a developing research area in today’s energy sector. Multifunctional materials have the potential to provide real-time monitoring of structures where temperature and pressure sensing is critical to its performance and efficiency. In this study, multifunctional materials are studied by embedding piezoelectric materials with two ongoing technologies, woven fabric composites and additive manufacturing (AM). The AM technology allows the flexibility of embedding a sensor within the structure, all while not compromising the mechanical performance requirements. The “smart parts” are fabricated modifying the standard additive manufacturing process, using …

An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan

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The continually growing market for metal components fabricated using additive manufacturing (AM) processes has called for a greater understanding of the effects of process variables on the melt pool geometry and microstructure in manufactured components for various alloy systems. Process Mapping is a general approach that traces the influence of process parameters to thermal behavior and feature development during AM processing. Previous work has focused mainly on Ti-6Al-4V (Ti64), but this work uses novel mathematical derivations and adapted process mapping methodologies to construct new geometric, thermal, and microstructural process maps for Ti64 and two nickel superalloy material systems. This work …

The Effect Of Laser Power And Scan Speed On Melt Pool Characteristics Of Pure Titanium And Ti-6al-4v Alloy For Selective Laser Melting, Chandrakanth Kusuma

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Selective Laser Melting (SLM) is an additive manufacturing (AM) technique that creates complex parts by selectively melting metal powder layer-by-layer. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy are melted on a substrate of the same material as powder using an in-house built SLM machine. Multiple combinations of laser power and scan speed are used for single bead fabrication while the laser beam diameter and powder layer thickness are kept constant. This experimental study investigates the influence of laser power, scan speed and …

Process Monitoring In Additive Manufacturing Aimed Toward Part Qualification, Shakerur Ridwan

Open Access Theses & Dissertations

Additive Manufacturing (AM), or layer-by-layer part fabrication, has played a tremendous role in the maker culture by allowing ideas to be materialized with limited resources or knowledge in manufacturing. Various cutting edge AM technologies exist today that are used to create end-use parts; however, these technologies are still new and the processes have not gone through the rigorous evaluation process that traditional manufacturing (i.e. milling, stamping, casting) methods have been through. As a result, several important questions arise when looking to adapt AM technology, including control of the manufacturing process, effect of manufacturing process on part properties, level of variance …

Freeze-Form Extrusion Fabrication Of Boron Carbide, Aaron Scott Thornton

Masters Theses

"Boron carbide is a safe, alternative to beryllium as a material for aerospace structures since it is also light-weight and exhibits high strength. This paper discusses a study of the Freeze-form Extrusion Fabrication (FEF) process to fabricate parts from boron carbide. Process parameters and hardware were modified to fabricate boron carbide specimens free of printed defects. Four-point bending tests were performed to measure the flexural strength of fabricated specimens. Observations of the presence of voids caused by ice crystals in fabricated parts led to further development and characterization of the boron carbide paste used with the FEF process. Additives were …