Mechanical Engineering Commons^™

Additively Manufactured Nature Inspired Morphology For Redesign: Advancing Next Generation Energy Systems, Vanshika Singh

Doctoral Dissertations

To meet cleaner energy goals and increasing demand, energy systems such as gas turbines and power plants are required to be operated under harsh loading conditions like higher temperatures and pressures, fluctuating loads, and corrosive environments. Advanced manufacturing techniques such as additive manufacturing (AM) have put us on the trajectory for next-generation system designs, allowing complex geometries and high-temperature alloys with tailored material properties. We need new and systematic design philosophies to use AM's unique characteristics prudently. For a given functionality, nature tends to provide similar solutions in animate and inanimate structures. We propose to take inspiration from nature's repetitive …

Laser Assisted Direct Writing Of Liquid Metal For Microprinting Applications, Olga Vargas Cruz

Theses and Dissertations

This paper presents a research study for potential printing of a Liquid Metal (LM) Eutectic Gallium Indium alloy (EGaIn) through the applications of the innovative additive manufacturing technology LIFT (Laser Induced Forward Transfer). LIFT is a precise printing technology that allows to create small, detailed printing. The liquid metal in study, EGaIn, has demonstrated great potential for microelectronics applications due to its minimum toxicity and high conductivity. Throughout this research different printing parameters are studied to comprehend the behavior of EGaIn printing with LIFT technique, these include laser energy, laser pulse, receiver material substrate, donor layer thickness, and …

An Investigation Into The Challenges Of Contemporary Additive Manufacturing: Insights Into The Metallurgical Response Of Materials And Relevant Solution, Huan Ding

LSU Doctoral Dissertations

Additive Manufacturing (AM) has gained attention in recent years due to its unique capabilities in the fabrication of complex parts. As with any new research, there is still a lack of sufficient understanding in the field of additive manufacturing, and further investigation is needed to solve existing problems. Ultimately, the aim is to enable the widespread use of AM components across various industries.

Chapter One provides a brief introduction to the background and current bottlenecks of additive manufacturing technology. Chapter two focuses on the development of high-strength 7075 aluminum alloy (Al7075) for Fused Deposition Modeling and Sintering (FDMS) technology. Al7075 …

Spall Characteristics Of Additively Manufactured Stainless Steel, Kevin Lamb

Doctoral Dissertations

Additive manufacturing (AM) has rapidly transformed from a novelty prototyping technology into a growing sector of production across a wide range of industries. Much work has been documented in literature to demonstrate the behavior of AM products under static and quasi-static loading conditions. However, the behavior of AM materials under high strain rate loading is not as well understood. This research attempts to advance the fundamental knowledge of the relationship between the unique aspects of AM and the mechanical performance under high velocity impact loading conditions.

This project examines the behavior of AM 316L stainless steel (SS) exposed to high …

In Situ Process Monitoring And Machine Learning Based Modeling Of Defects And Anomalies In Wire-Arc Additive Manufacturing, Eduardo Miramontes

Masters Theses

Wire Arc Additive Manufacturing (WAAM) has made great strides in recent years however, there remain numerous persistent challenges still hindering more widespread adoption. Defects in the parts produced degrade their mechanical performance. Inconsistency in the geometry of the weld beads or undesirable anomalies such as waviness, or humps can lead to loss of geometric accuracy and in extreme cases, when anomalies propagate to subsequent layers, build failure. Such defects can be mitigated by a controls framework, which would require a model that maps undesirable outcomes to information about the process that can be obtained in real time. This thesis explores …

Consumer 3d Printing For Remote Control Aircraft Wings: Development Of Novel Wingbox Structure, Ian Clark

University Honors Theses

Remote control aircraft construction and can be a very expensive and time-consuming hobby. With 3D printer consumer adoption rates skyrocketing, there is a gap between demand for RC aircraft and suitable well-designed models available to creators and hobbyists. By creating and testing two iterations of wingbox geometries, this research aims to help close that gap by producing an easily printable wing structure. While there are improvements that can be made on this work, this research has been effective in generating a novel wingbox structure for FFF 3D printing that has distinct advantages over other designs currently available.

Additive Manufacturing Of Stretchable Strain Sensors: Fabrication, Optimization And Application, John Nady Shihat Bastawrous

Theses and Dissertations

In this project, a novel strain sensor design is fabricated employing different additive manufacturing techniques. The spring sensor's primary material is PLA-Like resin with a nanocomposite encapsulation layer as the functional material. The main principle of Straining the sensors results in a change in resistivity as the distances among the conductive carbon particles change according to the strain applied.

Sensor fabrication consists of two parts: spring manufacturing and development of nanocomposite encapsulation The nanocomposite matrix is developed through the dispersion of Graphene and Carbon nanotubes in Thermoplastic Polyurethane through sonication and magnetic hotplate stirring. While the spring itself is manufactured …

Feasibility Of Thermoplastic Extrusion Welding As A Joining Method For Vacuum-Assisted Additively Manufactured Tooling, Chase C. Flaherty

Electronic Theses and Dissertations

In recent years, additive manufacturing (AM) has been successfully utilized for the production of large-scale composite tooling. Within these endeavors, however, limited research has focused on joining methods between printed sections. This work evaluates the feasibility of thermoplastic extrusion welding as a joining method for additively manufactured tooling structures. This joining method was assessed based on industry specifications of conventional thermoset tooling for wind blade manufacturing utilizing the vacuum-assisted resin transfer molding (VARTM) process. The specifications include requirements for the mechanical strength, vacuum integrity, roughness, and hardness of the tool surface. The feasibility of this welded polymer joint was demonstrated …

Cycle Time Reduction In Additive Manufacturing Using Peltier Thermoelectric Cooling Devices, Trevor Carlton

Honors College Theses

Thermoelectric cooling and the Peltier effect were discovered in 1834, over 188 years ago. Additionally, the first iterations of additive manufacturing (i.e., 3D printing) began in the early 1980s, more than 40 years ago. Despite these technologies’ age and years of advancements, the application of Peltier cooling-based devices in additive manufacturing has not yet been realized. These devices can be used for the active thermal management of print beds in 3D printers. Developing a mechanism to heat and cool a print bed can reduce the cycle time to manufacture a part. In 3D printing, waiting for the heated bed to …

Accelerating Manufacturing Decisions Using Bayesian Optimization: An Optimization And Prediction Perspective, Taofeeq Olajire

Graduate Theses, Dissertations, and Problem Reports

Manufacturing is a promising technique for producing complex and custom-made parts with a high degree of precision. It can also provide us with desired materials and products with specified properties. To achieve that, it is crucial to find out the optimum point of process parameters that have a significant impact on the properties and quality of the final product. Unfortunately, optimizing these parameters can be challenging due to the complex and nonlinear nature of the underlying process, which becomes more complicated when there are conflicting objectives, sometimes with multiple goals. Furthermore, experiments are usually costly, time-consuming, and require expensive materials, …

An Experimental Study On The Mechanical Properties And Chemical Composition Of Lcd 3d Printed Specimens, Sebastian Gomez

Electronic Theses and Dissertations

Additive manufacturing technologies have been enhanced throughout the years yet have surprised the manufacturing industry due to their high-end surface finish and dimensional accuracy. Different experiments have been done to identify a specific phenomenon known in the vat-polymerization field. Distortion and dimensional inaccuracy tend to affect the overall properties of the process, either physical or chemical. This approach allows the understanding of how the physical properties have been affected and how to study the chemical properties to avoid this type of phenomenon. The chemical reaction between polymer and UV light has been studied and experimented with to the point that …

A Machine Learning Approach To Robotic Additive Manufacturing Of Uv-Curable Polymers Using Direct Ink Writing, Luis A. Velazquez

LSU Master's Theses

This thesis presents the design and implementation of a robotic additive manufacturing system that uses ultraviolet (UV)-curable thermoset polymers. Its design considers future applications involving free-standing 3D printing by means of partial UV curing and the fabrication of samples that are reinforced with fillers or fibers to manufacture complex-shape objects.

The proposed setup integrates a custom-built extruder with a UR5e collaborative manipulator. The capabilities of the system were demonstrated using Anycubic resin formulations containing fumed silica (FS) at varying weight fractions from 2.8 to 8 wt%. To fully cure the specimens after fabrication, a UV chamber was used. Then, measurements …

Development And Evaluation Of Modeling Approaches For Extrusion-Based Additive Manufacturing Of Thermoplastics, Christopher C. Bock

Electronic Theses and Dissertations

This work focuses on evaluating different modeling approaches and model parameters for thermoplastic AM, with the goal of informing more efficient and effective modeling approaches. First, different modeling approaches were tested and compared to experiments. From this it was found that all three of the modeling approaches provide comparable results and provide similar results to experiments. Then one of the modeling approaches was tested on large scale geometries, and it was found that the model results matched experiments closely. Then the effect of different material properties was evaluated, this was done by performing a fractional factorial design of experiments where …

Modelling, Sensing, And Control Of Weld Beads In Gravity Aligned And Non-Gravity Aligned Orientations For Wire Arc Additive Manufacturing, Joshua J. Penney

Doctoral Dissertations

Wire Arc Additive Manufacturing (WAAM) has recently developed into a viable manufacturing process for large, complex metal parts. The WAAM process uses a Gas Metal Arc Welding (GMAW) torch mounted to an automated motion platform to execute a predetermined path plan based on a desired CAD geometry. As the desired geometry becomes more complex, it is advantageous to utilize out-of-position welding techniques used by human welders to stabilize the weld pool during the deposition of large overhangs. To ensure part accuracy and quality, adding layers of real-time control to manage various aspects of the WAAM process is critical. First, a …

Development Of Oxide Dispersion Strengthening (Ods) Alloys Powder For Additive Manufacturing, Changyu Ma

Graduate Theses, Dissertations, and Problem Reports

Additive manufacturing (AM) fabricated oxide dispersion strengthened (ODS) alloys are given high expectations for critical structural components such as the first stage turbine blade for their excellent creep strength and oxidation resistance compared to superalloys. However, the powder feedstock processing is still an open question since current state-of-the-art processes are not capable of achieving ultrafine strengthening elements such as Y₂O₃ in powder which leads to agglomeration issues in as-consolidated alloys. In this research, the oxidation behavior and stability of ultrafine oxide in AM-printed alloys using mechanically alloyed powders were evaluated at 1100 ^oC. In addition, a …

A Study Of Reduced Activation Ferritic Martensitic Metal Core Wire For Wire Arc Additive Manufacturing, Alexander L. Reichenbach

Electronic Theses and Dissertations

This study seeks to determine the technical feasibility of fabricating reduced activation ferritic martensitic (RAFM) steel parts, using a wire arc additive manufacturing (WAAM) process. The WAAM process, manufactures a part by depositing layers of metal onto a substrate to build a large scale near net shape part. RAFM alloy steels are next generation steels designed to resist radiation effects in the radiation intense working environments, such as nuclear reactors. To achieve this, process development and testing to design the WAAM production process with the custom RAFM filler wire was carried out. Several welding waveform modes were tested, and it …

Design And Fabrication Of A Polymer Fdm Printer Capable Of Build Parameter Monitoring And In-Sit Geometric Monitoring Via Photogrammetry, Travis Roberts

All Theses

Additive manufacturing, or 3D printing, is a complex process that creates free-form geometric objects by sequentially placing material in a location to construct an object, usually as a layer-by-layer process. One of the most widespread methods is Fused Deposition Modeling (FDM). FDM is used in many of the consumer-grade polymer 3D printers available today. While consumer grade machines are cheap and plentiful, they lack many of the features desired in a machine used for research purposes and are often closed-source platforms. Commercial-grade models are more expensive and are also usually closed-source platforms that do not offer flexibility for modifications often …

Assessing Mechanical Performance Of Dissimilar Steel Systems Made Via Wire-Arc Additive Manufacturing, Obed Daniel Acevedo

Masters Theses

Hot stamping is part of a specific type of metalworking procedure widely used in the automotive industry. This research seeks to help make hot stamp tooling component production more cost-effective by using large-scale additive manufacturing. Additive manufacturing can produce dissimilar steel components that can be more cost-effective and time-efficient and allow for complex geometries to be made. A dissimilar steel system consisting of 410 martensitic stainless steel and AWS ER70S-6 mild steel is proposed to make hot stamps, making them more cost-efficient. However, the material interface's mechanical behavior in 410SS-mild steel additively manufactured material systems is not well understood. This …

Additive Manufacturing Of Cork, A Cold Spray Technology, Kimberly Kay Dickey

Theses and Dissertations

Cold Spray Additive Manufacturing is a technology capable of mass manufacturing components with complicated geometry and coating substrates in hard-to-reach areas. In addition, cold spray also has the ability of conducting a green manufacturing process, with zero waste of renewable feed material, and zero gas and chemical emission. This paper investigates solely cold spray as an additive manufacturing technology with cork as the natural material. CFD results were used to predict the physical behavior of air and the cork particles. After unsuccessful coatings, final results showed that when moisture is added, cork is successfully cold sprayed, and agglomeration is experienced. …

Transients In Plastic Instabilities During Thermo-Mechanical Reversals In An Additively Manufactured Ti6al4v, Sabina C. Kumar

Doctoral Dissertations

A complex interaction of process variables in an evolving geometry during Additive Manufacturing (AM), can bring about spatial and temporal transients of temperature and stress within each layer in a part. Although AM shares commonalities with conventional processing techniques such as casting, welding, and thermo-mechanical process, published literature has shown that the steady-state conditions are not strictly valid during AM process. Macro-scale fluctuations of thermal gradients (dT/dx: 10³ to 10⁷ K/m) combined with local changes in thermal expansion coefficients, crystallographic strains and localized stress-strain constitutive properties in conjunction with thermal cycles, can bring about a plastic strain gradient …

Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications, William Anderson

Electronic Thesis and Dissertation Repository

Due to sensor size and supporting circuitry, in vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this thesis is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in biomechanical applications. The capacitive transducer membrane of the FXTH87 was modified, and a relationship was reported between applied compressive deformation and sensor signal value. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. Finite element analysis was an effective tool to …

Med-Drop Pill Dispenser, Cole Pike, Taylor Morris, Christopher Bruni, Jose Gomez

Mechanical Engineering

Veterans’ Affairs home care nurses currently spend anywhere from thirty minutes to two hours filling out monthly prescriptions one pill at a time to veterans who are unable to leave their homes. The goal of this project was to create an easy-to-use device that could be left at a patient’s home that nurses could use to quickly and accurately dispense medication into the patient’s monthly pill box.

Design Of A Cable-Driven Manipulator For Large-Scale Additive Manufacturing, Phillip Chesser

Masters Theses

Additive manufacturing of concrete is a growing field of research, yet current motion platforms do not offer viable routes towards large scale deployable systems. This thesis presents the design and analysis of a novel cable-driven robot for use in large scale additive manufacturing. The system developed, termed SkyBAAM, is designed to be easily deployable to a construction site for on-site additive manufacturing of buildings and other large structures. The design philosophy behind this system is presented. Analysis of this system first explores the kinematics, and stiffness as a function of cable tension. Analysis of the workspace and singularities is also …

Development Of In-Situ Radiometric Inspection Methods For Quality Assurance In Laser Powder Bed Fusion, Cody S. Lough

Doctoral Dissertations

“Laser Powder Bed Fusion (LPBF) metal Additive Manufacturing (AM) fabricates 3D metal parts layer-by-layer. The process enables production of geometrically complex parts that are difficult to inspect with traditional methods. The LPBF parts experience significant geometry driven thermal variations during manufacturing. This creates microstructure and mechanical property inhomogeneities and can stochastically cause defects. Mission critical applications require part qualification by measuring the defects non-destructively. The layer-to-layer nature of LPBF permits non-intrusive measurement of radiometric signals for a part’s entire volume. These measurements provide thermal features that correlate with the local part health. This research establishes Optical Emission Spectroscopy (OES) and …

Design For Additive Manufacturing (3d Printing), Michael O'Donnell, Michael J. Levy

Williams Honors College, Honors Research Projects

The goal of this project is to study the performance of a 3D printed mechanical part subjected to topology optimization. A part that is somewhat complex in its load bearing and geometry will be selected. That part will then be designed, finite element analysis will be performed on it to optimize its topology, and then it will be 3D printed and tested. The goal of topology optimization is to either save material cost and/or part weight due to the ability of 3D printing to manufacture parts with complex and obscure geometry.

Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am, Sayed Ehsan Saghaian N.E.

Theses and Dissertations--Mechanical Engineering

Laser Powder Bed Fusion (L-PBF) is one of the most promising Additive Manufacturing (AM) methods to fabricate near net-shape metallic materials for a wide range of applications such as patient-specific medical devices, functionally graded materials, and complex structures. NiTi shape memory alloys (SMAs) are of great interest due to a combination of unique features, such as superelasticity, shape memory effect, high ductility, work output, corrosion resistance, and biocompatibility that could be employed in many applications in automotive, aerospace, and biomedical industries. Due to the difficulties with traditional machining and forming of NiTi components, the ability to fabricate complex parts, tailor …

Study On The Viability Of Preparing Plaster Molds For Rapid Prototyping Of Complex Ceramic Parts Using The Lost Pla Method, Shelton F. Fowler Iv

Honors College Theses

In the field of metal casting, cast parts often require an internal cavity to be made to meet design requirements. Frequently, these interior surfaces are not manufacturable through standard machining processes, and even when possible, they would most likely involve expensive and time-consuming operations. In order to avoid these machining costs, expendable ceramic or sand cores are manufactured and placed into the mold to allow the direct casting of complex internal geometries. This research seeks to use relatively inexpensive plastic 3D printing technology and the lost PLA casting process for the production of low-cost and rapidly producible ceramic cores. A …

Development Of A Process For Thermal And Mechanical Modelling Of Screw-Driven Pellets Extrusion, Kaixiang Shi

Master’s Theses

The overall goal of the thesis project is to develop a process for thermal and mechanical modelling of the screw-driven pellets extrusion process, and applying the model results to design extruder temperature and flow rate controllers.

The proposed extruder is designed for metal 3D printing. The device demonstrates great potential in tackling some of the major issues faced by the metal additive manufacturing community. It eliminates the use of metal powder for workplace and workers safety. It is able to produce end-use parts with industrial grade mechanical and microstructural properties. It utilizes low cost metal-loaded polymer pellets as feedstock. However, …

Hydrokinetic Turbine Composite Blades And Sandwich Structures: Damage Evaluation And Numerical Simulation, Mokhtar Fal

Doctoral Dissertations

“Composite materials are gaining interest due to their high strength to weight ratio. This study deals with both experimental and numerical approaches to cover the aspects of the failure of composite materials in hydrokinetic turbine applications. In Part I, the location and magnitude of failure in the horizontal axis water turbine carbon fiber-reinforced polymer (CFRP) composite blades with different laminate stacking sequences were investigated. Two lay-up orientations were adopted for this work ([0⁰]₄ and [0⁰/90⁰]_2s). A finite element analysis model was generated to examine the stresses along the blade. Five angles were introduced to study the effect …

Influence Of Input Energy On Mechanical Properties Of Laser Powder Bed Fused Aisi 304l Stainless Steel, Tan Pan

Masters Theses

“Powder Bed Fusion process with selective laser melting technique is popularly adopted in additive manufacturing area on account of its layer by layer manufacturing fashion capable of fabricating components with complex internal and external geometries and structures. However, the process-property map is unique and vital for different materials and AM configurations used for fabrication. The process parameter is identified as a significant factor that heavily influences the properties and performances of the printed materials.

Current work aimed to extend the existing knowledge on Laser Powder Bed Fusion fabricated AISI 304L by accessing the influence of varying energy input on the …