Mechanical Engineering Commons^™

Residual Stress Generation In Additive Manufacturing Of Complex Lattice Geometries, Katie Bruggeman, Nathan Klingbeil, Anthony N. Palazotto

Faculty Publications

Residual stresses developed during additive manufacturing (AM) can influence the mechanical performance of structural components in their intended applications. In this study, thermomechanical residual stress simulations of the laser powder bed fusion (LPBF) process are conducted for both simplified (plate and cube-shaped) geometries as well as five complex lattice geometries fabricated with Inconel 718. These simulations are conducted with the commercial software package Simufact Additive©, which uses a nonlinear finite element analysis and layer-by-layer averaging approach in determining residual stresses. To verify the efficacy of the Simufact Additive© simulations, numerical results for the plate and cube-shape geometries are analyzed for …

Energy Efficiency In Additive Manufacturing: Condensed Review, Ismail Fidan, Vivekanand Naikwadi, Suhas Alkunte, Roshan Mishra, Khalid Tantawi

Engineering Technology Faculty Publications

Today, it is significant that the use of additive manufacturing (AM) has growing in almost every aspect of the daily life. A high number of sectors are adapting and implementing this revolutionary production technology in their domain to increase production volumes, reduce the cost of production, fabricate light weight and complex parts in a short period of time, and respond to the manufacturing needs of customers. It is clear that the AM technologies consume energy to complete the production tasks of each part. Therefore, it is imperative to know the impact of energy efficiency in order to economically and properly …

Damage Detection With An Integrated Smart Composite Using A Magnetostriction-Based Nondestructive Evaluation Method: Integrating Machine Learning For Prediction, Christopher Nelon

All Dissertations

The development of composite materials for structural components necessitates methods for evaluating and characterizing their damage states after encountering loading conditions. Laminates fabricated from carbon fiber reinforced polymers (CFRPs) are lightweight alternatives to metallic plates; thus, their usage has increased in performance industries such as aerospace and automotive. Additive manufacturing (AM) has experienced a similar growth as composite material inclusion because of its advantages over traditional manufacturing methods. Fabrication with composite laminates and additive manufacturing, specifically fused filament fabrication (fused deposition modeling), requires material to be placed layer-by-layer. If adjacent plies/layers lose adhesion during fabrication or operational usage, the strength …

Numerical Study Of Solar Receiver Tube With Modified Surface Roughness For Enhanced And Selective Absorptivity In Concentrated Solar Power Tower, Shawn Hatcher, Mathew Z. Farias, Jianzhi Li, Peiwen Li, Ben Xu

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Concentrated solar power (CSP) is a reliable renewable energy source that is progressively lowering its cost of energy. However, the heat loss due to reflected and emitted radiation hinders the maximum achievable thermal efficiency for solar receiver tubes on the solar tower. Current solar selective coatings cannot withstand the high temperatures that come with state-of-the-art CSP towers often needing to be recoated soon after initial operation. We intend to use Inconel 718 with different additive manufacturing (AM) practices to construct surfaces that allow for more light-trapping to occur. By adjusting printing parameters, we can tailor a surface to allow for …

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 …

Design Of Machine Tool Cross Beam Using Metal Big Area Additive Manufacturing, Tyler Poon

Masters Theses

The modern world would not be what it is now without machine tools. Advances in materials and processes, such as carbon fiber and additive manufacturing (AM), enable the design space for machine tool components to expand. However, machine tool components require accurate geometry, which is not available from parts produced by metal Big Area Additive Manufacturing (mBAAM). This project outlines the process in which a traditionally manufactured machine tool component, a welded box structure on an existing machine tool, was redesigned to be made using mBAAM. The goal was to design a structure that was printable using the MedUSA system …

Image Segmentation With Human-In-The-Loop In Automated De-Caking Process For Powder Bed Additive Manufacturing, Vincent Opare Addo Asare-Manu

Theses and Dissertations

Additive manufacturing (AM) becomes a critical technology that increases the speed and flexibility of production and reduces the lead time for high-mix, low-volume manufacturing. One of the major bottlenecks in further increasing its productivity lies around its post-processing procedures. This work focuses on tackling a critical and inevitable step in powder-bed additive manufacturing processes, i.e., powder cleaning or de-caking. Pressing concerns can be raised with human involvement when performing this task manually. Therefore, a robot-driven automatic powder cleaning system could be an alternative to reducing time consumption and increasing safety for AM operators. However, since the color and surface texture …

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 …

Fast-, Light-Cured Scintillating Plastic For 3d-Printing Applications, Brian G. Frandsen, Michael Febbraro, Thomas Ruland, Theodore W. Stephens, Paul A. Hausladen, Juan J. Manfredi, James E. Bevins

Faculty Publications

Additive manufacturing techniques enable a wide range of possibilities for novel radiation detectors spanning simple to highly complex geometries, multi-material composites, and metamaterials that are either impossible or cost prohibitive to produce using conventional methods. The present work identifies a set of promising formulations of photocurable scintillator resins capable of neutron-gamma pulse shape discrimination (PSD) to support the additive manufacturing of fast neutron detectors. The development of these resins utilizes a step-by-step, trial-and-error approach to identify different monomer and cross-linker combinations that meet the requirements for 3D printing followed by a 2-level factorial parameter study to optimize the radiation detection …

Material Extrusion-Based Additive Manufacturing: G-Code And Firmware Attacks And Defense Frameworks, Haris Rais

Theses and Dissertations

Additive Manufacturing (AM) refers to a group of manufacturing processes that create physical objects by sequentially depositing thin layers. AM enables highly customized production with minimal material wastage, rapid and inexpensive prototyping, and the production of complex assemblies as single parts in smaller production facilities. These features make AM an essential component of Industry 4.0 or Smart Manufacturing. It is now used to print functional components for aircraft, rocket engines, automobiles, medical implants, and more. However, the increased popularity of AM also raises concerns about cybersecurity. Researchers have demonstrated strength degradation attacks on printed objects by injecting cavities in the …

Exploring Additive Manufacturing In A Space Environment - A Capstone Design Project Experience, Zain Zafar Khan, Zachary Alan Sobelman, Sharanabasaweshwara Asundi

Mechanical & Aerospace Engineering Faculty Publications

The employment of additive manufacturing in the non-standard environments like space, ships, or submarines has the potential to be an advanced utility not only in the pre-flight production of aerospace components and structures, but also for the onboard manufacturing of components and tools necessary for future space missions. For example, the ability to produce tools and structural components on the International Space Station can provide the space community the opportunity to make repairs and upgrades to the space station without wasting time and resources transporting such materials through additional missions. Additive manufacturing would allow for space missions to use on …

A Numerical Simulation Of The Powder Bed Additive Manufacturing Process With Molecular Dynamics Simulation, Yeasir Mohammad Akib

Theses and Dissertations

Many manufacturing industries utilize powder bed fusion (PBF) since it can produce microscale precision 3D parts. During PBF, powder particles are selectively fused layer by layer using thermal energy. The build quality in the PBF process relies heavily on powder bed properties and thermal energy deposition. Powder flowability, spreadability, and packing fraction are some of the insightful factors that determine the quality of the powder bed. In this study, a two-dimensional powder bed is developed using the LAMMPS package. A cloud-based pouring of powders with varying volumes and initialization is adopted for the work. A blade-type and circular recoater is …

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 …

Influence Of Nano-Sized Sic On The Laser Powder Bed Fusion Of Molybdenum, Nathan E. Ellsworth, Ryan A. Kemnitz, Cayla C. Eckley, Brianna M. Sexton, Cynthia T. Bowers, Joshua R. Machacek, Larry W. Burggraf

Faculty Publications

Consolidation of pure molybdenum through laser powder bed fusion and other additive manufacturing techniques is complicated by a high melting temperature, thermal conductivity and ductile-to-brittle transition temperature. Nano-sized SiC particles (0.1 wt%) were homogeneously mixed with molybdenum powder and the printing characteristics, chemical composition, microstructure, mechanical properties were compared to pure molybdenum for scan speeds of 100, 200, 400, and 800 mm/s. The addition of SiC improved the optically determined density and flexural strength at 400 mm/s by 92% and 80%, respectively. The oxygen content was reduced by an average of 52% over the four scan speeds analyzed. Two mechanisms …

Automated Posture Positioning For High Precision 3d Scanning Of A Freeform Design Using Bayesian Optimization, Zhaohui Geng, Bopaya Bidanda

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Three-dimensional scanning is widely used for the dimension measurements of physical objects with freeform designs. The output point cloud is flexible enough to provide a detailed geometric description for these objects. However, geometric accuracy and precision are still debatable for this scanning process. Uncertainties are ubiquitous in geometric measurement due to many physical factors. One potential factor is the object’s posture in the scanning region. The posture of target positioning on the scanning platform could influence the normal of the scanning points, which could further affect the measurement variances. This paper first investigates the geometric and spatial factors that could …

Additive Manufacturing Of Molybdenum For High Temperature Structural Applications, Megan L. Bustin

Theses and Dissertations

This research considered additive manufactured (AM) molybdenum (Mo) and the effect of three variables on microstructure, mechanical properties, and the relationship between the two. Test temperature, laser speed, and shield gas or build atmosphere were varied, and samples tested and analyzed using a three-point bending test, chemical composition, and optical and scanning electron microscopy. The relationship among variables and results using a Design of Experiments was limited compared to the inclusion of every tested sample. Most effects were expected: samples tested at room temperature were brittle without statistical significance; increasing laser speed resulted in decreased ductility and strain, smaller grain …

Ultrafast Laser Ablation Of Inconel 718 For Surface Improvement, Sampson Canacoo, Enrique Contreras Lopez, Oscar Coronel, Farid Ahmed, Jianzhi Li, Anil K. Srivastava

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Inconel 718 is considered difficult to machine because of its ability to maintain its properties at high temperatures. The low thermal conductivity of the alloy causes accelerated tool deterioration when machining. Selective laser melting (SLM) additive manufacturing introduces a possibility of eliminating these difficulties, and producing complex shapes with this difficult-to-machine material. However, high surface roughness and porosity usually occur at the surface of components produced through additive manufacturing. In this study, the surfaces of Inconel 718 samples produced through selective laser melting were treated using laser ablation. The process parameters for the laser ablation process were analyzed in …

Optimizing Build Plate Adhesion Of Polymers In Fused Granule Fabrication Processes, Alex Schroeder, Jason Weaver

Faculty Publications

Perhaps the most crucial element of fused granule fabrication (FGF) is material adhesion; in order to achieve a successful product, the material being printed must adhere to the build plate. For optimal products, the material should only adhere to the build plate until the print is complete, then be easily removable. This paper examines the effects of different build plates, environments, and bonding agents on material adhesion during the FGF process in a CNC mill machine. The force to remove polycarbonate (PC) and polypropylene (PP) from build plates was tested with various bonding agents. Except in one case, the adhesive …

A Comparison Of Layer Deposition And Open Molding Of Petg By Fused Pellet Fabrication In An Additive Manufacturing System, Alex Gibson, Jason Weaver

Faculty Publications

Additive manufacturing continues to offer new possibilities in both production and economics. The industry has quickly adopted it to rapidly produce parts that would be difficult or cost preventative otherwise. Recent innovation has expanded its capabilities, however there are still significant limitations. Most AM processes are restricted by materials available, in producing large parts, or by not achieving material deposition speeds to make certain products feasible. In addition, tight tolerances for features and surfaces cannot be produced without substantial post processing. High-speed Fused Pellet Fabrication (FPF) in combination with Hybrid Manufacturing (HM) offers expanded capabilities as additive and subtractive process …

Additively Manufactured Polymer And Metal Lattice Structures With Eulerian Path, Adeeb Ibne Alam

Electronic Theses and Dissertations

Lattice structure manufacturing with polymers and metals can benefit from the use of Eulerian paths. In this research, two types of lattice fabrication methods are studied where the Eulerian path can be applicable. Polymer lattice is improved by using a new assembly design, while a new way of metal lattice fabrication is discussed.

For the fused filament fabrication process, a new interlocking design and assemble-based lattice structure building approach is investigated by increasing continuity in layers and avoiding support structures. To minimize contour plurality, Eulerian paths between the edges were enforced. Two configurations in the form of cubic and octet …

Additive Manufacturing Of Aluminum Alloy By Metal Fused Filament Fabrication (Mf3)., Luke J. Malone

Electronic Theses and Dissertations

This research studies metal-fused filament fabrication (MF3) for manufacturing aluminum alloy parts. An aluminum alloy powder-based feedstock with a polymer-binder system was extruded via capillary rheometry to form a filament. The filament was used to print green parts that were involved in a two-step debinding process combining solvent and thermal extraction of the polymer binder, then sintered in a partial vacuum. Resulting grain structure, sintered density, and mechanical properties will be characterized and compared to metal injection molded (MIM) specimens. The main objective is to gain an understanding of the MF3 process characteristics and the ensuing material properties and microstructure …

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 …

Autonomous Material Refill For Swarm 3d Printing, William C. Jones

Mechanical Engineering Undergraduate Honors Theses

3D printing currently offers robust and cheap rapid prototyping solutions. While standard 3D printing remains at the periphery of mass production, the technology serves as a starting point for the development of swarm manufacturing. Since swarm manufacturing is predicated upon autonomy, swarm technology companies such as AMBOTS are seeking to minimize human involvement in the swarm’s functions. At present, the 3D printing swarm consists of the printers, a transporter which can take them between job sites, and the floor tiles which provide power and support the build surfaces. To add to this ecosystem, this project is focused on the design …

Multistage Modeling Of Fatigue Of Ti-6al-4v Fabricated By Different Additive Manufacturing Techniques, Lionardo Lado, Saeed Ataollahi, Mohammad J. Mahtabi

Honors Theses

Thanks to its high strength-to-weight ratio and corrosion resistance, Ti-6Al-4V has gained a lot of attention in additive manufacturing (AM) of complex parts with aerospace and medical applications. The realistic loading condition in these applications is mostly cyclic. However, the main challenge with AM of this alloy - and in general AM of metallic parts - is fatigue resistance and durability of the part, which has been reported to be much lower than the conventional materials. In this study, fatigue life performance of three additive manufacturing methods was compared using the Multistage Fatigue model (MSF). MSF model predicts the fatigue …

Effects Of Varied Oxygen Levels, Laser Powers, And Scanning Speeds On Manufactured Components By Laser-Based Powder Bed Fusion, Amelia Mcnamee

Honors College Theses

This project addresses the effects of oxygen concentration, laser power, and scanning speed on the melt pool geometry of laser-based powder bed fusion (L-PBF) additively manufactured components. A parametric analysis using the substrate alone was conducted to determine a range of desirable laser powers and scanning speeds. The parameter with the more significant effect will be decided upon based on the depth-to-width ratios (D/W) of the resultant laser weld bead. A range of oxygen levels and scan speeds was selected for the next phase. These samples were then be analyzed for depth-to-width ratios. It was expected that higher oxygen concentrations …