Mechanical Engineering Commons^™

Failure Mode, Effects And Criticality Analysis Of A Very Low Earth Orbit Cubesat Mission, Robb Christopher Borowicz

Mechanical & Aerospace Engineering Theses & Dissertations

When space programs launch vehicles into orbit, multiple failures could arise throughout the mission and corrective actions are often not an option. Applying reliability engineering approaches during the design phase focuses on analyzing risk by anticipating potential failures and mitigating uncertainties in the design. Old Dominion University, in partnership with the U.S. Coast Guard Academy, and the U.S. Air Force Institute of Technology designed and developed a 3U CubeSat mission to validate on-orbit, three space technology payloads. Mission SeaLion will fly as a secondary payload on stage two of Northrop Grumman’s Antares rocket and will be deployed in a very …

Mechanics Of Preimpregnated Fiber Tow Deposition And Compaction, Virginia Meredith Rauch

Mechanical & Aerospace Engineering Theses & Dissertations

In additive manufacturing, such as Automated Fiber Placement (AFP), defects often develop during the deposition and compaction of preimpregnated composite material, which reduce the strength of the resultant material. It is necessary to reduce defects and have good adhesion between plies to optimize the laminate performance and reduce delamination between composite layers. The aim of this work is to study the adhesion and deformation of preimpregnated (prepreg) composite material during the deposition and compaction stage in the composite forming process and how material parameters can be used to increase laminate strength. Two types of experimentation were performed on thermoset IM7/8552 …

Examining The Different Snap-Through Characteristics Of Bistable Cfrp Composite Laminates, Vishrut Deshpande

All Theses

Bistable carbon fiber composites, whose bistability arises from having asymmetric fiber layouts in different layers, have shown immense potential for use in shape morphing and adaptive structure applications. While many studies in this field focus on these composite laminates’ external shapes at the two stable states, their snap-through behavior of shifting from one stable shape to the other remains a critical aspect to be investigated in complete detail. Moreover, symmetric loading conditions have been extensively studied based on the classical lamination theory, but the asymmetric loading conditions received far less attention. Therefore, this study examines an asymmetric, localized point load …

A Central Compact Hybrid-Variable Method With Spectral-Like Resolution, Md Mahmudul Hasan

Open Access Theses & Dissertations

Numerical methods for hyperbolic conservation laws have been a driving force for theresearch in scientific computing and simulation science in the past decades, as many physical, biological, and engineering systems are governed by these equations, such as fluid mechanics, tumor growth, and virtual wind tunnel simulations. Despite the existence of many schemes in the literature, people have never stopped searching for more accurate and efficient methods for these problems. Indeed, the increasing complexity of systems in emerging applications demands better resolution of sub-grid scale phenomenon whereas classical methods usually fail to deliver high-fidelity simulation results of such systems within realistic …

Rheological Behavior Of Dspc-, Dbpc-, And Dppc-Oxygen Microbubbles And Their Effectiveness In Improving Survival In A Rat Model Of Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome, Riaz Ur Rehman Mohammed

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

Acute respiratory distress syndrome (ARDS) causes 75,000 deaths in the U.S., annually. It is characterized by hypoxemia and damage to the lung alveoli. ARDS Management strategies involve extracorporeal membrane oxygenation (ECMO) and mechanical ventilation, but none of these methods improve the mortality rates. Oxygen microbubbles (OMBs) consist of a lipid shell with an oxygen core and have potential to augment oxygenation to manage ARDS. Previous studies demonstrated significant improvements in systemic oxygenation and mortality upon administering OMBs.

We replicated an ARDS rat model by intratracheal administration of lipopolysaccharide at a 24 mg/kg dose. After inducing the disease in rats, the …

Ambient Temperature Phase Change Launcher, Johnny Molloy

Senior Honors Projects

JOHNNY MOLLOY (Mechanical Engineering) Ambient Temperature Phase Change Launcher Sponsor: Bahram Nassersharif (Mechanical Engineering)

Deployment of payloads stored in watertight cylindrical bodies in underwater environmental conditions are of interest to the marine and naval community. The proposed work will investigate the possibility of using inert carbon dioxide gas compressed into its liquid state and stored under pressure to launch payloads by means of expansion from a cylindrical tube. To suit the needs of the Naval Undersea Warfare Center (NUWC), this launching system must fire from up to 14 ft underwater, have two degrees of freedom, and the payload must not …

Corrosion Assessment Of Biodegradable Metal Implants For Orthopedic Applications, Wendy B. Reynoso-Diaz

Honors Theses

Magnesium alloys are the most promising materials to be used as biodegradable implants mainly due to their superior biocompatibility and lower specific density compared to other biodegradable metals (i.e., zinc and iron-based alloys). This study is investigating the effect of two different manufacturing methods and purity levels on the corrosion rates of a novel Mg-Zn-Ca-Mn-based alloy. Experimental in vitro corrosion tests were conducted on the biocompatible Mg-Zn-Ca-Mn-based alloy fabricated using conventional casting and hot rolling with low and high purity levels. The experimental research conducted, assessed the corrosion rates of the following Mg-1.2Zn-0.5Ca-0.5Mn-based alloys: Hot Rolled High Purity, As-Cast High …

Atomic Force Microscopy Based Dna Sensing And Manipulation, Matthew Shubert

Mechanical Engineering Undergraduate Honors Theses

Sequencing DNA provides a positive impact for the biomedical community by understanding a wide variety of applications such as human genetics, disease, and pathogens. The reason the Arkansas Micro & Nano Systems lab is involved with research in DNA sequencing is due to the current, leading industry method. Nanopore sequencing was developed by Oxford Nanopore Technology in which its sequencing method separates double stranded DNA to electrically characterize individual nucleotides traveling through a charged nanopore. Unfortunately, nanopore sequencing uses biological materials that require a shelf life and drives high cost. Therefore, the Arkansas Micro & Nano Systems lab has developed …

Biofidelic Considerations For Improving Standardized Airflow And Firmness Testing For Infant Sleep Products, Wyatt D. Davis

Boise State University Theses and Dissertations

Background

Over the last 30 years, 83 infant fatalities (113 reported, 30 incidental) directly involving crib bumpers have been reported to the Consumer Product Safety Commission. Of these reports, 90% are for infants under a year old, with 61% occurring for infants between 1 and 4 months of age (Safety, 2020). There are currently a few regulations governing the design of crib bumper products, but none test the suffocation risk associated with these products using biofidelic methods.

Goals

We sought to explore the development of new testing methods that can determine the safety of different products and are physiologically representative …

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

LSU 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 …

Strain-Based Design Of Steel-Polymer-Steel Composite Pipes, Vul Thang

LSU New Orleans Theses and Dissertations

Many offshore single-wall pipelines and structural failures have occurred in the past. As a result, lives were lost, and billions of dollars were spent. In addition, natural disasters such as earthquake fault zones can cause a large volume of soil movement. This can easily damage single-wall pipelines or piles of fixed offshore platforms in the earthquake fault zone.

Currently, the single-wall pipelines are used for the offshore and onshore oil and gas industry. This research investigated the use of double-wall composite pipe steel-polymer-steel (SPS) in place of single-wall pipe to prevent such failures. The double-wall composite pipe has a larger …

Cal Poly Fluid Power Vehicle Challenge 2022, Sangmin Sung, Eddy Rodriguez, Travis Welch, Jeremy Baechler, Kevin Pauls

Mechanical Engineering

In this report, the Featherweight Cycles design team puts forth the scope and overview of their design project, discusses background research and competitor analysis, and presents the project’s final design and manufacturing plans. The overall goal of this project is to fabricate and compete in the Fluid Power Vehicle Challenge, hosted by the National Fluid Power Association. To better define the design process, the team researched previous year’s designs from Cal Poly, as well as winning designs from the last two years to form a baseline of knowledge about competing schools’ designs. After researching multiple design paths, Featherweight Cycles chose …

Cfd Simulation Of Varying Fuel Jet Placement Of Mach 2 Flow (Poster), Sara Broad

Honors Capstone Projects

No abstract provided.

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 …

Investigating The Application Of Flettner Rotors On The Great Lakes, Garrett C. Bond

Senior Honors Theses

Climate change is quickly becoming one of the leading problems of the twenty-first century, and the maritime transportation sector is beginning to react. Wind propulsion technologies have been making a comeback led by the Flettner rotor. The deck-mounted, vertical, spinning cylinder generates a lift (or thrust) force perpendicular to the wind by utilizing the Magnus effect. Rotor performance has been studied extensively on many ocean shipping routes, but has not been on the Great Lakes, a region with a large maritime industry. This study aims to assess whether or not Flettner rotors are practical in the region by calculating propulsive …

Properties Of 25cr7ni Stainless Steel Fabricated Through Laser-Powder Bed Fusion., Arulselvan Arumugham Akilan

Electronic Theses and Dissertations

Stainless steel is a low carbon high alloyed system with higher concentrations of Cr& Ni, which impart high corrosion resistance to them. Alloys with approximately 25% Cr & 7% Ni in their chemical composition are commercially referred to as ‘Super Duplex Stainless Steel’. They have a unique phase composition of approximately 50% ferrite & 50% austenite, yielding a robust combination of high mechanical strength & corrosion resistance. They find extensive interest & application in the fields which demand a longer service life under intense mechanical / corrosive environment such as offshore oil rigs & pipelines in nuclear power plants. Traditional …

Nucleate Boiling Under Different Gravity Values: Numerical Simulations & Data-Driven Techniques., Sandipan Banerjee

Electronic Theses and Dissertations

Nucleate boiling is important in nuclear applications and cooling applications under earth gravity conditions. Under reduced gravity or microgravity environment, it is significant too, especially in space exploration applications. Although multiple studies have been performed on nucleate boiling, the effect of gravity on nucleate boiling is not well understood. This dissertation primarily deals with numerical simulations of nucleate boiling using an adaptive Moment-of-Fluid (MoF) method for a single vapor bubble (water vapor or Perfluoro-n-hexane) in saturated liquid for different gravity levels. Results concerning the growth rate of the bubble, specifically the departure diameter and departure time have been provided. The …

Fluid Structure Interactions Within A Common Rail Diesel Injector., Russell Prater

Electronic Theses and Dissertations

The internal flow of a high-pressure diesel injector is simulated numerically to investigate the complex transient flow structures and the unsteady forces imparted to the injector needle that result from the asymmetric flow fields developed during operation. The gas-liquid two phase flow is simulated using a mixture model with the cavitation numerically modeled using the Zwart-Gerber-Belamri model. Both the k-ε model and the detached eddy simulation (DES) model are used, and the numerical results are compared. This dissertation looks at the internal flow of a generic injector at different lifts and characterizes the flow parameters at high lift and low …

Generative Designs Of Lightweight Air-Cooled Heat Exchangers, Connor Miller

Mechanical Engineering Undergraduate Honors Theses

The development of high-performance air-cooled heat exchangers is required to permit the rapid growth of vehicle and aircraft electrification. In electric vehicles and airliners, the motors and power electronics are integrated into a compact space, leading to unprecedently high power density. To achieve higher overall thermal efficiency, the heat exchangers must be extremely light while maintaining their heat transfer performance and mechanical robustness. Recently advances in 3D metal printing, e.g., direct metal laser sintering, and selective laser melting, have enabled the manufacturing of high-performance robust heat exchangers by eliminating thermal boundary resistance and ensuring a uniform thermal expansion coefficient. Nonetheless, …

Durability Of Non-Metallic Materials For Additively Manufactured Heat Spreader Fabrication, Rafael Estrella

Mechanical Engineering Undergraduate Honors Theses

Power electronics are necessary to convert power from DC sources for AC applications. As this technology trends toward smaller packaging for denser power loads, the increased electrical losses result in deleterious excess heat. Thermal management devices are required to prevent the effects of thermal runaway from shortening the longevity of these modules. Nonmetallic jet impingement heat spreaders provide several benefits in terms of weight and performance over conventional cold plates while not accentuating EMI from the switches in the power module; however, the polymer makeup of the materials previously used for fabricating these devices raises durability concerns under the high …

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 …

Suitability Of Low-Cost Additive Manufacturing For Polymer Electrolyte Fuel Cells, David Alexander

Open Access Theses & Dissertations

The purpose of this dissertation is to study the feasibility of low-cost additive manufacturing to fabricate polymer electrolyte fuel cell bipolar plate materials. Traditional manufacturing techniques include molding, milling, hollow embossing, hydro-forming, rolling, and electromagnetic forming. These processes are employed when a design has been selected due to higher costs at low volumes. The combination of high initial costs and bipolar plates being the most expensive component of the polymer electrolyte fuel cell creates incentive to mitigate this obstacle. The feasibility of low-cost additive manufactured bipolar plates will be proven by fabrication, post-processing, and characterization of printed test specimen. The …

Material Synthesis And Additive Manufacturing Of Ceramics, Elsa Bramasco-Rivera

Open Access Theses & Dissertations

This research is divided into two main topics: vitrimer polymers and alumina ceramics. Additive manufacturing is an emerging technology. In this research, two main methods of additive manufacturing are used: material extrusion and vat photopolymerization. The hypothesis of self-healing and mechanochromism functionalities was tested through the synthesis of vitrimers, a novel material combining properties of both thermosets and thermoplastics. These vitrimers were 3D printed using material extrusion. Casted vitrimers showed stiffening effects after submergence in water. Lithography based ceramics have gained attention in recent years due to their wide range of applications. Alumina ceramics were additively manufactured using digital light …

Application Of The Continuum Damage Mechanics Wilshire-Cano-Stewart (Wcs) Model, Jaime Aaron Cano

Open Access Theses & Dissertations

In this study, the applications of the continuum damage mechanics-based Wilshire-Cano-Stewart (WCS) model are explored to predict rupture time, minimum-creep-strain-rate (MCSR), damage, damage evolution, and creep deformation. Increase knowledge in manufacturing methods has pushed the limit of material science and the development of new materials. Conventional testing is required to qualify materials against creep which according to the ASME B&PV III code, 10,000+ hours of experiments are necessary for each heat before materials are put into service. This process is costly and not feasible for new materials. As an alternative, models have been employed to predict creep behaviors and reduce …

Femtosecond Laser Machining Of Drilled Holes In Silicon Nitride, Stephani Nevarez

Open Access Theses & Dissertations

In this study, the laser drilling parameters of a Nd:YAG ultrashort pulsed laser are evaluated to produce zero taper through holes on silicon nitride ceramics. Manufacturing of ceramics is expensive and difficult because of the mechanical and thermal properties of ceramics, limiting applications. Additionally, the high level hardness of the ceramic can affect the ceramic and the manufacturing tool. There is a need to explore non-contact machining such as laser machining to expand the uses of ceramics in industry applications.In order to accomplish this goal, understanding of the physical mechanisms that occurs while laser ablation is needed. Furthermore, the minimum …

All-In-One Multi3d System: Exploring Potential Of 5-Axis Material Extrusion Additive Manufacturing, Angel Vega

Open Access Theses & Dissertations

Additive Manufacturing (AM) has experienced consistent growth since its inception across its seven process categories, especially Material Extrusion (MEX) with systems that can be seen in commercial and industrial settings. As MEX evolves, innovation can be traced in the growing variety of available process materials and new system capabilities leading to greater interest in the technology across various industries including automotive, aerospace and even nuclear weapons. This has created an increasing demand for end-use parts from MEX systems leading to more complex machines with additional Degrees of Freedom (DoF), specialized workflows, and expanded post processing that address the drawbacks of …

Development Of High Conductivity Copper Coatings For Srf Cavity, Himal Pokhrel

Physics Theses & Dissertations

The development of metallic coatings with high purity and high thermal conductivity at cryogenic temperature could be very important for application to the superconducting radiofrequency (SRF) cavity technology. The deposition of such bulk coatings on the outer surface of a niobium cavity could result in higher heat conductance and mechanical stiffness, both of which are crucial for enhancing the cavity performance at a reduced cost.

Cold spray technology was used to deposit bulk coatings of pure copper and copper-tungsten alloys on the niobium substrate and the samples of size 2 mm × 2 mm cross section were cut and subjected …

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 …

Ng-Torque/Tension Testing Of Bolts With Epoxy Primer, Gabrielle Van Brunt

Undergraduate Honors Capstone Projects

This capstone project is in conjunction with Northrop Grumman (NG). The goal of the project is for NG to apply an epoxy in the future to aerospace structures that they produce. This epoxy is meant to prevent corrosion of threaded joints in the structures. Although NG has the epoxy and has no issues procuring it, NG does not know the properties of the epoxy; it cannot be used until the epoxy’s nut factor is experimentally determined. The epoxy nut factor will be used for design and drawing purposes on various projects. To determine the nut factor, the Aggiepoxy team created …

Material Synthesis And Machine Learning For Additive Manufacturing, Jaime Eduardo Regis

Open Access Theses & Dissertations

The goal of this research was to address three key challenges in additive manufacturing (AM), the need for feedstock material, minimal end-use fabrication from lack of functionality in commercially available materials, and the need for qualification and property prediction in printed structures. The near ultraviolet-light assisted green reduction of graphene oxide through L-ascorbic acid was studied with to address the issue of low part strength in additively manufactured parts by providing a functional filler that can strengthen the polymer matrix. The synthesis of self-healing epoxy vitrimers was done to adapt high strength materials with recyclable properties for compatibility with AM …