Mechanical Engineering Commons^™

Advancements And Challenges In Additively Manufactured Functionally Graded Materials: A Comprehensive Review, Suhas Alkunte, Ismail Fidan, Vivekanand Naikwadi, Shamil Gudavasov, Mohammad Alshaikh Ali, Mushfig Mahmudov, Seymur Hasanov, Muralimohan Cheepu

Engineering Technology Faculty Publications

This paper thoroughly examines the advancements and challenges in the field of additively manufactured Functionally Graded Materials (FGMs). It delves into conceptual approaches for FGM design, various manufacturing techniques, and the materials employed in their fabrication using additive manufacturing (AM) technologies. This paper explores the applications of FGMs in diverse fields, including structural engineering, automotive, biomedical engineering, soft robotics, electronics, 4D printing, and metamaterials. Critical issues and challenges associated with FGMs are meticulously analyzed, addressing concerns related to production and performance. Moreover, this paper forecasts future trends in FGM development, highlighting potential impacts on diverse industries. The concluding section summarizes …

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …

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 …

Point Heat Source Correlation To Microstructural Evolution In Advanced Manufacturing, Mark Anderson

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Although there are different ways that advanced manufacturing can be performed, the use of single-point heat sources has become the standard to control a final product’s properties. It is imperative to understand how the heat source used in the different advanced manufacturing processes affect the microstructure of interest. The intimate relationship between the heat source and microstructure allows for controlling and tailoring a part’s properties. Utilizing different microstructural analysis, the cross-correlation of various point heat sources to developed microstructure was conducted in this dissertation.

Laser powder bed fusion allows for unique print-to-part protocols, but the dynamics of the process makes …

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 …

Performance Evaluation Of Composite Sandwich Structures With Additively Manufactured Aluminum Honeycomb Cores With Increased Bonding Surface Area, M. Rangapuram, S. K. Dasari, Joseph William Newkirk, K. Chandrashekhara, H. Misak, P. R. Toivonen, D. Klenosky, T. Unruh, J. Sam

Materials Science and Engineering Faculty Research & Creative Works

Modern aerostructures, including wings and fuselages, increasingly feature sandwich structures due to their high-energy absorption, low weight, and high flexural stiffness. The face sheet of these sandwich structures are typically thin composite laminates with interior honeycombs made of Nomex or aluminum. Standard cores are structurally efficient, but their design cannot be varied throughout the structure. With additive manufacturing (AM) technology, these core geometries can be altered to meet the design requirements that are not met in standard honeycomb cores. This study used a modified aluminum honeycomb core, with increased surface area on the top and bottom, as the core material …

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 …

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 …

Additive Manufacturing Of Complexly Shaped Sic With High Density Via Extrusion-Based Technique – Effects Of Slurry Thixotropic Behavior And 3d Printing Parameters, Ruoyu Chen, Adam Bratten, Joshua Rittenhouse, Tian Huang, Wenbao Jia, Ming-Chuan Leu, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing of dense SiC parts was achieved via an extrusion-based process followed by electrical-field assisted pressure-less sintering. The aim of this research was to study the effect of the rheological behavior of SiC slurry on the printing process and quality, as well as the influence of 3D printing parameters on the dimensions of the extruded filament, which are directly related to the printing precision and quality. Different solid contents and dispersant- Darvan 821A concentrations were studied to optimize the viscosity, thixotropy and sedimentation rate of the slurry. The optimal slurry was composed of 77.5 wt% SiC, Y2O3 and Al2O3 …

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 …

Tini-Based Bi-Metallic Shape-Memory Alloy By Laser-Directed Energy Deposition, Yitao Chen, Cesar Ortiz Rios, Braden Mclain, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In this study, laser-directed energy deposition was applied to build a Ti-rich ternary Ti–Ni–Cu shape-memory alloy onto a TiNi shape-memory alloy substrate to realize the joining of the multifunctional bi-metallic shape-memory alloy structure. The cost-effective Ti, Ni, and Cu elemental powder blend was used for raw materials. Various material characterization approaches were applied to reveal different material properties in two sections. The as-fabricated Ti–Ni–Cu alloy microstructure has the TiNi phase as the matrix with Ti2Ni secondary precipitates. The hardness shows no high values indicating that the major phase is not hard intermetallic. A bonding strength of 569.1 MPa was obtained …

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 Continuous Carbon Fiber-Reinforced Sic Ceramic Composite With Multiple Fiber Bundles By An Extrusion-Based Technique, Ruoyu Chen, Adam Bratten, Joshua Rittenhouse, Ming-Chuan Leu, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Due to the high cost, complex preparation process and difficulty in structural design, the traditional methods for carbon fiber reinforced SiC ceramic composite preparation have great limitations. This paper presents a technique for the additive manufacturing multiple continuous carbon fiber bundle-reinforced SiC ceramic composite with core-shell structure using an extrusion-based technique. A conventional nozzle system was modified to print simultaneously a water based SiC paste with continuous carbon fibers. Different levels of binder contents were investigated to optimize the stickiness, viscosity, thixotropy and viscoelasticity of the paste. After sintering, SiC whiskers were generated on the surface of fiber, which is …

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 …

Open Source 3d-Printable Planetary Roller Screw For Food Processing Applications, Marcello C. Guadagno, Jacob M. Loss, Joshua M. Pearce

Michigan Tech Publications

Historically, open source agriculture (OSA) was based on grassroots technology generally manufactured by hand tools or with manual machining. The rise of distributed digital manufacturing provides an opportunity for much more rapid lateral scaling of open source appropriate technologies for agriculture. However, the most mature distributed manufacturing area is plastic, which has limited use for many OSA applications. To overcome this limitation with design, this study reports on of a completely 3D-printable planetary roller screw linear actuator. The device is designed as a parametric script-based computer aided design (CAD) package to allow for the easy adaption for a number of …

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 …

Design, Fabrication, And Reliability Effects Of Additively Manufactured First Level Compliant Interconnects For Microelectronics Application, Tumininu David Olatunji

Graduate Theses and Dissertations

Semiconductor packaging and development is greatly dependent on the magnitude of interconnect and on-chip stress that ultimately limits the reliability of electronic components. Thermomechanical related strains occur because of the coefficient of thermal expansion mismatch from different conjoined materials being assembled to manufacture a device. To curb the effect of thermal expansion mismatch between conjoined parts, studies have been done in integrating compliant structures between dies, solder balls, and substrates. Initial studies have enabled the design and manufacturing of these structures using a photolithography approach which involves a high number of fabrication steps depending on the complexity of the structures …

Modeling And Analysis For Unit Cell Size, Material Anisotropy And Material Imperfection Effects Of Cellular Structures Fabricated By Powder Bed Fusion Additive Manufacturing., Yan Wu

Electronic Theses and Dissertations

Cellular structures are networks of interconnected struts or walls with porosities and are widely found in many natural load-bearing structures such as plants and bones. Cellular structures offer unique functional characteristics such as high stiffness to weight ratio, tailorable heat transfer coefficient, and enhanced mechanical energy absorption, which makes them highly attractive in various engineering disciplines such as biomedical implants, electrodes, heat exchangers, and lightweight structures. There exists an abundance of literatures that have investigated various mechanical properties of various cellular structures such as Poisson’s ratio, elastic modulus, ultimate strength, yield strength, and failure characteristics. Based on the classic cellular …

The Effect Of Compaction Temperature And Pressure On Mechanical Properties Of 3d Printed Short Glass Fiber Composites, Pushpashree Jain Ajith Kumar Jain

Mechanical & Aerospace Engineering Theses & Dissertations

Among many thermoplastics that are used in engineering, polyamide 6 (nylon 6) is an extremely versatile engineering thermoplastic. Nylon filled with glass fibers has higher mechanical strength and high wear resistance than general purpose nylon. 3D printed composites, based on fused filament modeling, typically suffer from poor bead-to-bead bonding and relatively high void content, limiting their mechanical properties

This thesis explores the effect of compaction pressure and temperature on improving the mechanical properties of 3D printed composites. Engineering moduli in the printing and transverse to printing direction, as well as ultimate strength were measured using the tensile testing with Digital …

Laser Powder Bed Fusion Of Nitihf High-Temperature Shape Memory Alloy: Effect Of Process Parameters On The Thermomechanical Behavior, Mohammadreza Nematollahi, Guher P. Toker, Keyvan Safaei, Alejandro Hinojos, S. Ehsan Saghaian, Othmane Benafan, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia

Mechanical Engineering Faculty Publications

Laser powder bed fusion has been widely investigated for shape memory alloys, primarily NiTi alloys, with the goal of tailoring microstructures and producing complex geometries. However, processing high temperature shape memory alloys (HTSMAs) remains unknown. In our previous study, we showed that it is possible to manufacture NiTiHf HTSMA, as one of the most viable alloys in the aerospace industry, using SLM and investigated the effect of parameters on defect formation. The current study elucidates the effect of process parameters (PPs) on the functionality of this alloy. Shape memory properties and the microstructure of additively manufactured Ni-rich NiTiHf alloys were …