Mechanical Engineering Commons^™

Temporal Forecasting Of High-Rate Dynamic Using Physics-Informed Machine Learning And Hardware-Software Co-Design, Puja Chowdhury

Theses and Dissertations

Due to aging, fatigue, corrosion, and even natural disasters; the health of the structure is prone to degradation throughout its service life. The explosively-fast growing efforts on Structural health monitoring (SHM) always try to exploit different aspects of the automation of damage detection, localization, and prognosis tasks. One of the main challenges is the hardware and software co-design to implement the model in real-life situations. On the other hand, the fast-advancing artificial intelligence draws the researchers' attention to adopt different data-driven approaches in this field. This brings other challenges like domain-specific model adaptation, data bias, data scarcity, model validation by …

Development Of A Haptic System For Robot-Assisted Femur Fracture Surgery, Fayez H. Alruwaili

Theses and Dissertations

Robot-assisted surgery has emerged within the field of surgical technology, driven by the need for greater accuracy and speed in the ongoing evolution of healthcare. This advancement has influenced numerous areas requiring enhancements to achieve optimal surgical results. However, surgical robotics tends to lack the surgeon’s connection to the operation, creating a gap in the intuitive skill set required for successful operations. The gap is seen through the lack of sense of touch, which may result in tissue damage and additional injury when the robot interacts with the patient. Furthermore, challenges faced during femur fracture surgery have positioned robot-assisted surgery …

Effect Of Gas Tungsten Arc Welding Process Variants On The Microstructure And Properties Of Az31b Magnesium Alloy And 304hcu Austenitic Stainless Steel Welds, Srinivasan S

Theses and Dissertations

The automotive and aero sectors seek materials with high specific strength & specific stiffness for enhanced efficiency / emission control. Mg alloys, known for their low density, are used in the as-cast, and wrought forms, depending on the service requirements, and are predominantly used for non-loaded structural parts in varied engineering applications. Welding Mg alloys is of great interest to industry, not only for the fabrication of components but for the repair welding of casting as well. There has been considerable research in the fusion & solid-state welding of Mg alloys. Gas tungsten arc welding (GTAW) has often been preferred …

Identification Of Delamination Defect In Fibre Reinforced Polymer Composite Tapered Plate Based On Vibration Measurement, Venkatesan M

Theses and Dissertations

Fibre-reinforced polymer (FRP) composite plates have been widely used in various engineering applications due to their high strength-to-weight ratio, corrosion resistance, and durability. Despite their many benefits, Delamination is a separation of the layers in composite material and can occur due to various factors such as impact, fatigue, and manufacturing defects. Identifying delamination in composite structures is crucial for ensuring safety and reliability. In this study, model-dependent vibration methods, which are an effective non-destructive technique, were utilised for delamination identification. The primary objective is to investigate the dynamic behaviour of delaminated thickness-tapered plates and develop a reliable methodology for delamination …

Thermodynamic Modeling Of Uranium Nitride With Select Actinides And Fission Products, Eric Reece Mcmanus

Theses and Dissertations

Uranium mononitride fuel is being investigated as a potential nuclear fuel for a Westinghouse lead-cooled fast reactor due to factors such as its high uranium density, high melting point, and favorable thermal conductivity. To obtain an understanding of the thermochemical behavior of UN fission products and minor actinides, thermodynamic data was obtained from various resources to create a database to represent the behavior of the fuel. This database was used to generate an Ellingham diagram to represent the relative thermodynamic stability of the phases over the reactor temperature range. A simulation was run computing the equilibrium state of the fuel, …

Microchannel Slip Flow Characteristics By Time Travel After Photobleaching Velocimetry, Brandon James Sellers

Theses and Dissertations

Interfacial science follows the study of observing behavior between two or more phases of matter when in contact. For example, a liquid solution passes through a microchannel, and the walls interact with the fluid shearing along the surface. The fluid particles develop momentum changes from interfacial phenomena and slip along the wall begins to affect the fluid body. Slip flow is a name for the phenomenon, and with it, modeling velocity for the interfacial behavior demands both resolution and minimal interference. Laser-induced fluorescence photobleaching anemometry (LIFPA) works as a sound method for acquiring data on microchannel flow, but it needed …

The Effect Of Chromium Coatings On Hydrogen Uptake In Zirconium Alloy Nuclear Fuel Cladding, Jorie Lyn Walters

Theses and Dissertations

The amount of hydrogen in a nuclear reactor can have a profound impact on its performance and safety when it is absorbed into or released from fuel rods. Hydrogen pickup in modern fuel cladding materials has been minimized by alloying additions and microstructural texture engineering, but these materials are still susceptible to hydrogen release during high temperature oxidation. The nuclear accident at the Fukushima Daiichi power plant in 2011 resulted in hydrogen gas production and subsequent explosions which led the United States Department of Energy to initiate a program to develop enhanced nuclear fuel cladding materials. New cladding materials include …

A Holistic Quality Management Model For Optimization Of Quality Assurance In Manufacturing, Devon Blakeney Clark

Theses and Dissertations

Quality Management (QM) is essential in manufacturing to ensure products are consistent and functional every time. Consumers expect high quality products that last, and industries unable to accomplish this are destined to fail. Therefore, product quality has always been at the forefront of manufacturer decision making, though it is normally viewed as a given more than as a goal. This means that businesses want quality because it is needed for their survival, but there has not been consideration for how to incorporate innovation into this essential field. Quality needs to be viewed holistically with regards to all manufacturing factors that …

A Plug-And-Produce Connectivity Framework For Manufacturing Systems, Theodros Abraham Tarekegne

Theses and Dissertations

The Industrial Internet of Things (IIoT) movement has birthed technologies that enable the fusing of physical and digital environments. However, the extensive number of available options for industrial communication and data formatting has remained a barrier to achieving digital knowledge synonymy in industry. There have been previous attempts to establish standards for industrial connectivity and communication, but legacy machines, as well as custom and non-proprietary devices, still face issues communicating data with other manufacturing equipment. To address these challenges, the Industrial Internet of Things initiative has led to the creation of the Plug and Produce (PnP) concept to facilitate the …

Experimental And Computational Understanding Of Solid Oxide Iron Air Battery Performance, Chaitali Morey

Theses and Dissertations

Long-duration energy storage (LDES) (10+ hours) is considered a key technical solution for a widespread penetration of renewable energy into the utility market. However, the currently available storage technologies are limited to less than 10 hours for cost reasons. The benchmark Li-ion battery technology would be economically prohibitive if the storage time goes beyond 4 hours. Therefore, developing new low-cost LDES-compatible battery technologies is highly desirable. A solid oxide iron air battery (SOIAB) has been developed which consists of a reversible solid oxide cell (RSOC) and energy storage unit (ESU) of an iron bed. This battery is considered a promising …

Crystal Plasticity Modeling Of Heterogeneous Microstructure Of Additively Manufactured Metals, Md Mahabubur Rohoman

Theses and Dissertations

Additive manufacturing (AM) has emerged as a promising technique in the manufacturing industry for producing complex metal components as it provides shape freedom and simplistic processing chain.

Powder bed fusion is the widely used AM technique that uses laser or electron beam as the energy source to melt the metal powder and deposit it in a layer-by-layer fashion. While doing so, the previously molten layers are constantly are in re-heating and re-cooling processes which end up creating an intricate solidification for the deposited layers. Due to the complexity involved in the thermal cycles for the solidification process, columnar grains develop. …

Application Of Machine Learning Techniques And The Unscented Kalman Filter To Real-Time Gas Turbine Clearance Prediction, Donald Earl Floyd

Theses and Dissertations

The growth in renewable energy sources and retirement of large baseload coal-fired power stations has led to an accompanying decrease in reliability and security of the electrical grid. Since renewable energy sources are typically non-dispatchable, this can lead to blackouts and/or brownouts for customers. Heavy duty gas turbine power plants (HDGT) offer a solution to this problem. HDGTs are dispatchable, clean, and offer flexibility in the fuel they consume, but operational limitations must be well understood to fully exploit their benefits.

One of the main operational limitations is the tip clearances in the gas turbine. In many cases, the gas …

Enhanced Two-Phase Heat Spreading Enabled By Dropwise Condensation, Kai Luo

Theses and Dissertations

The rapidly increasing power density of electronic systems has raised challenges for thermal management. Efficient heat spreading plays an important role in distributing high-density heat to the large-area heat sink and maintaining the junction temperature below the temperature limit during operation. Vapor chambers, a type of flat heat pipe utilizing two-phase heat transfer and fast travel of vapor flow, can achieve far more efficient two-dimensional heat spreading than most conduction-based thermal ground plane materials. By promoting dropwise condensation in vapor chambers, the thermal performance and scalability can be further improved due to the enhanced condensation heat transfer and unique droplet …

Simultaneous Crack & Wave Propagation And Acoustic Emission Signal Modelling Using Peri-Elastodynamic, Md Mushfiqur Rahman Fahim

Theses and Dissertations

This work presents the use of Peri-Elastodynamic, a guided wave simulation method based on meshfree non-local Peridynamics theory. To model simultaneous crack and wave propagation simulation and its application on Acoustic Emission (AE) signal modelling, a new formulation is presented. The field of nondestructive evaluation (NDE) and structural health monitoring (SHM) is slowly embracing the advancement in Machine Learning (ML) / Artificial Intelligence (AI) for better and cost-effective assessment of structures and damage prediction. AI/ML can revolutionize the NDE/SHM field by automating the data collection and analyzing processes. However, the big challenge is that the model needs a sheer amount …

Tribology Of Mos2 Thin Films Stabilized By A Chromium Underlayer And Max Phase, Nihal Ahmed

Theses and Dissertations

MoS2 is a popular solid lubricant with limited application at room temperature due to its’ sensitivity to atmospheric oxygen and humidity. This thesis focuses on the stabilization of molybdenum disulfide (MoS2) coatings on aluminum substrates to enhance their tribological performance at room temperature. MoS2 exhibits exceptional lubricating properties in vacuum conditions, but its reactivity with atmospheric oxygen leads to the formation of abrasive molybdenum trioxide (MoO3), restricting its effectiveness in ambient environments. This thesis investigates the effects of a Chromium underlayer and the incorporation of MAX phase (Ti3SiC2) on the tribological performance and chemical stability of MoS2 solid lubricant. Physical …

Natural Language Processing For Automated Sysml Diagram Generation, Joshua Andre Ontiveros

Theses and Dissertations

This thesis explores the applications of natural language processing (NLP) techniques in model-based system engineering (MBSE) to help generate System Modeling Language (SysML) diagrams. MBSE is a method that aids in enhancing traditional engineering practices by modeling to help improve understanding and communication in systems development. SysML, one of the modeling languages for MBSE, helps represent a system's architecture, behavior, and information flow. Translating systems requirements and specifications into SysML models can be time-consuming and can lead to errors when created manually. Automating the creation of SysML diagrams from textual descriptions with the help of NLP techniques can aid in …

Advancements In Aerial Vehicle Platforms: A Guide For Design, Validation, And Implementation Of 3d Printed Drones, Alan Salvador Urteaga

Theses and Dissertations

Additive manufacturing methods have revolutionized the way products are designed and developed through a product's entire design life cycle. This is in part correlated with the nature of additive manufacturing methods that differentiate them from traditional methods. Some of the benefits of additive manufacturing methods include customizability, rapid prototyping, the production of complex design geometry, and embedded assembly manufacturing. Unmanned aerial vehicles have been on the rise for various military, commercial, or personal applications. The focus of this study is to provide detailed instructions on how to engineer a viable drone design that is impact-resistant, modular, and customizable. This study …

In Situ Shear Exfoliation Of Layered Materials And Fabrication Of Multifunctional Composites, Md Abdur Rahman Bin Abdus Salam

Theses and Dissertations

To harness the extraordinary properties of 2D nanomaterials across a range of applications, including but not limited to device fabrication (such as sensors and transistors), energy storage and conversion systems (like batteries and solar cells), as well as biomedical applications (such as drug delivery and tissue engineering), it is imperative to achieve proper synthesis to single-layer form from bulk material, ensuring defect-free synthesis. Recognizing the criticality of defect-free synthesis and high yield for nanocomposite production, our focus centered on developing a facile, contamination-free, single-step, in situ shear exfoliation process for bulk materials (such as graphene, hBN, coal) within elastomers, which …

Feature Extraction From Vibration Signature Acquired From Railroad Bearing Onboard Condition Monitoring Sensor Modules, Kevin Quaye

Theses and Dissertations

The University Transportation Center for Railway Safety (UTCRS) has designed an onboard monitoring system that tracks vibration waveforms over time, to obtain a direct and more accurate indicator of bearing health. The data collected by these sensors is used for vibrational analyses of the bearings. The speed of the bearing is a fundamental parameter needed to carry out the analysis. GPS data can be used to determine bearing speed if available; however, due to size, cost and power constraints GPS is typically not available at the sensor location. This means that analysis must be delayed until the data is uploaded …

Bridging Human Emotion And Autonomous Vehicle Control: Reinforcement Learning Enhancements In The Carla Simulator, Timothy Marion Jude Lyons

Theses and Dissertations

Autonomous vehicles are a key component for an evolution in transportation as they may lead to increased safety and productivity. As autonomous vehicles advance industries will look to further increase customer satisfaction through personalized experiences for autonomous vehicle passengers. Reinforcement learning may be the key to success for autonomous vehicles. The development of autonomous vehicles, utilizing reinforcement learning, which consider the emotions of the passenger, will be a breakthrough for the automotive industry. This thesis presents a unique approach to autonomous vehicles developed with reinforcement learning which consider the human emotions of the passenger. It is a stepping stone to …

Attachment Of 2d Nanomaterials Onto 1d Nanofibers For Separation And Sensing Applications, Elmmer A. Vera Alvarado

Theses and Dissertations

Advancing materials for water desalination and sensing is essential for tackling global issues related to clean water and efficient energy systems. This thesis explores the application of 2D nanomaterials, specifically graphene, integrated onto 1D poly(vinylidene fluoride) (PVDF) nanofibers to enhance their effectiveness in these areas. Utilizing innovative techniques such as Forcespinning® and plasma treatment, PVDF nanofibers were strengthened with graphene and conductive polymers like poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). The research involved thorough assessments using direct contact membrane distillation (DCMD) systems, oil-water separation tests, and various mechanical and electromechanical evaluations. Heat-pressed membranes consistently delivered a flux of 0.33 kg/m²/hr and …

Investigating The Fatigue Life Of Asymmetric And Novel Helical Gear Drives, Rajesh S

Theses and Dissertations

The present research work investigates the contact and bending fatigue life of asymmetric helical gear and novel helical gear based on the finite element analysis. In the first phase, the contact and bending fatigue life of the asymmetric helical gear drives is estimated based on the strain life approach.

Further, a parametric study is carried out to investigate the influence of important helical gear parameters such as module, pressure angle, helix angle, gear ratio, teeth number and face width on contact and bending fatigue life of asymmetric helical gear drives. It is noted that the asymmetric helical gear shows a …

Surface Acoustic Waves-Based Point-Of-Care Biosensor, Debdyuti Mandal

Theses and Dissertations

A biosensor is an analytical tool consisting of biologically active material used in close conjunction with a device that converts a biochemical signal into a quantifiable electrical signal. The early detection of the disease biomarkers can enhance the increased curability of the disease, reduce healthcare costs, and finally, improve the quality of life for patients. Thus, for the following purpose, there is always a need for an effective biosensor as a diagnostic device. The biosensor typically consists of an actuator, a bio-recognition component, and a transducer that converts captured signals into a meaningful display. The bio-recognition component uses biomolecules to …

Multidimensional Simulation Of Cool Diffusion Flame, Ejaz Ahmed

Theses and Dissertations

Understanding the behavior of spherical cool diffusion flames in microgravity conditions is crucial for advancing combustion research. This knowledge has significant implications for both fundamental science and practical applications, such as spacecraft fire safety and the development of advanced, high-efficiency engines that benefit from low-temperature chemistry. Spherical cool diffusion flames are typically characterized by peak temperatures between 500 and 1000K and are often followed by the radiative extinction of a hot flame. Some low-temperature ignitions can sustain indefinitely at around 700K, leading to chain-branching pathways that produce intermediate species such as C2H4, H2O2, HO2, CH2O, CH3O, and HCO. In some …

Accelerating Numerical Modeling And Optimization Of Structural Mechanical Systems, Fatemeh Hashemian

Theses and Dissertations

This research proposal presents Bayesian optimization and reduced order modeling methods to accelerate numerical analysis and design of structure mechanical system. First, a holistic framework of Bayesian optimization (BO) based on parameterized numerical models and genetic algorithm-guided adaptive sampling is developed to automate and accelerate the design of a front-loading washing machine. The research aims to address challenges associated with the model parameterization and global optimization and design. A multibody dynamics model of the washing machine incorporating a set of 9 key design variables is developed. The design variables are implemented to enable automated modifications of the dynamics model for …

Development Of A Large Format Additive Manufacturing System Based On An Off-The-Self Pellet Extruder, Aywan Das

Theses and Dissertations

Large Format Additive Manufacturing (LFAM), or Big Area Additive Manufacturing (BAAM), was introduced to resolve the limitations of the low deposition rate, low scalability, and therefore long print times, of traditional 3D printing methods when applied to the manufacturing of large structures and tooling. LFAM can be used to overcome the high conventional tooling costs of large structures. However, even with robotic setups, LFAM still mainly relies on quasi-planar, 2.5D printing strategies. This fails to reap the advantages of multi-axis printing, such as improved adhesion, reduced support material use, and the ability to create complex curved surfaces. In this research, …

Enhancement Of Polytetrafluoroethylene-Polyvinyl Alcohol Nanofibers Triboelectric Effect With Carboxylic Functionalized Multiwalled Carbon Nanotubes Coating, Fernando Viesca

Theses and Dissertations

In this study, we fabricated a TENG using Forcespinning® (FS) Polytetrafluoroethylene microfibers (FS-PTFE-MFs) and Electrospun (ES) Polyvinyl alcohol nanofibers (ES-PVA-NFs). The FS-PTFE-MFs were physically linked with functionalized carboxylic multiwall carbon nanotubes (MWCNTs-COOH) employing water dispersions. MWCNTs-COOH were dispersed using three different surfactants: Sodium Dodecyl Sulfate (SDS), Sodium dodecylbenzenesulfonate (SDBS), and Triton X-100 (TX-100). Coated FS-PTFE-MFs were then characterized using a field emission scanning electron microscope (FESEM) with an energy dispersive X-ray spectroscopy (EDS) attachment and Fourier-transform infrared spectroscopy (FTIR). While no significant difference in performance was observed with different surfactants, electrical results of the TENG recorded a notable enhancement of …

Development Of A Mechanical Boot For Prevention Of Deep Vein Thrombosis In Outpatients, Julian David Trevino

Theses and Dissertations

This work presents the development of a mechanical boot designed to prevent Deep Vein Thrombosis (DVT) in high-risk individuals such as those who have just had major procedures. DVT is a serious condition characterized by the formation of blood clots in the deep veins, particularly of the lower limbs, which can lead to life-threatening complications if not adequately addressed. The mechanical boot utilizes the principle of Continuous Passive Motion (CPM) to facilitate blood flow in the lower extremities, thereby mitigating the risk of clot formation. Through a combination of mechanical engineering, biomedical research, and user centered design, the project outlines …

Repair And Surface Functionalization Of Fiber Reinforced Polymer Composites By Cold Spray, Ibnaj Anamika Anni

Theses and Dissertations

Fiber-reinforced polymer composites are widely used in industries and applications such as energy, automotive, defense, and aerospace. This study investigates the application of polymer cold spray, an emerging additive manufacturing process, for coating and repair of fiber-reinforced polymer (FRP) composites. The research starts with feasibility studies focused on the cold spray deposition of thermoplastic nylon-6 particles on woven glass fiber-reinforced composites (GFRP). A parametric study determines critical process parameters window, ensuring successful deposition and bonding without compromising the macroscale mechanical behavior. These findings indicate that the cold spray process does not adversely affect the fiber integrity or surface quality of …

Design, Fabrication, And Characterization Of Multifunctional Cellular Structures For Enhanced Impact Energy Mitigation Performance, Kazi Zahir Uddin

Theses and Dissertations

This dissertation investigates the relationship between the structural design of cellular solids and their macroscopic behavior and focuses on the customization of properties through advanced fabrication techniques. The concepts of density gradation and their integration in both non-ordered and ordered cellular structures have been proposed. The investigation focuses on the development of functionally graded foam materials (FGFMs) and mechanical metamaterials to obtain tunable mechanical performance. One significant focus is the fabrication of density-graded foam stacks with various interface adhesives. From the insights gained from the study of interfaces in density-graded foams, certain design and fabrication principles are applied to enhance …