Mechanical Engineering Commons^™

Turbulent Shockwave/Boundary-Layer Interactions Generated By Sharp Swept Fins, Dustin Levi Otten

Mechanical and Aerospace Engineering Dissertations

The shock/turbulent boundary layer interaction (STBLI) generated by a sharp fin with a 60 deg leading edge sweep mounted above a flat plate at Mach 2.5 was studied numerically. Incipient separation due to this highly swept fin was determined by varying the fin angle to the incoming freestream. The effect of a small fin/plate gap on STBLI incipient separation was established. Sweeping the fin increases the deflection required for incipient separation as the sweep reduces the interaction strength. A gap causes flow leakage under the fin, further reducing the interaction strength on the windward side. The incipient angle of attack …

Method-Of-Characteristics Models For Flowfield Evaluation Of Hypervelocity Test Facilities, Anannthkumar Jayamani

Mechanical and Aerospace Engineering Dissertations

Ground test facilities are an imperative part of the design and development of flying vehicles. In the case of high-enthalpy facilities, evaluating the gasdynamic and thermochemical state of the test gas poses challenges due to high temperature effects. This study aims to contribute to the development impulse facilities by developing reduced-order models resolving the flowfields of such facilities. Developed as a part of this study are various method-of-characteristics (MoC) algorithms which consider gases under varying levels of thermochemical complexity. The algorithms span from simple calorically perfect gases to full thermochemical nonequilibrium. The first set of algorithms was limited to unsteady …

Non-Intrusive Reduced Order Model Formulation For Inverse Shape Design Including Deforming Meshes And Multiphysics Problems., Kapil Aryal

Mechanical and Aerospace Engineering Dissertations

Despite significant advancements in computer capabilities for numerical simulations, engineers continue to face limitations when dealing with large-scale full-order model(FOM) simulations. These simulations often necessitate repeated solves, such as those encountered in inverse design, real-time solution prediction, error quantification, and solver convergence, among others. To address these challenges, reduced order modeling (ROM) has emerged as a valuable approach. This thesis focuses on the development of an ROM framework that combines Proper Orthogonal Decomposition (POD) with machine learning techniques. This integrated approach is applied to a diverse range of heat transfer and fluid flow inverse design problems. POD constructs optimal sets …

Cooperative Manipulation And Formation Control Using Multiple Aerial Vehicles, Uluhan Cem Kaya

Mechanical and Aerospace Engineering Dissertations

Recent advancements in autonomous systems have significantly impacted both academia and industry, opening new research avenues. One of them is the collaboration of multiple systems to achieve a common goal, which is known as a cooperative system. In the lack of human intelligence, decision making and perception capabilities, uncrewed autonomous systems could mutually benefit from each other’s capabilities when they are deployed and utilized together. This research tackles the collaboration of group of uncrewed aerial systems (UASs) where the constraint on individual vehicles requires a varying level of coordination and cooperation. Such cooperation can be in the form of a …

Microstructural Finite Element Modeling Of High-Performance Carbon Fiber-Reinforced Composites To Characterize Microscale Material Properties And Fiber-Direction Compressive Strength, Quy Tung Ling Vu

Mechanical and Aerospace Engineering Dissertations

Carbon fiber-reinforced composites are increasingly used in aerospace application thanks to their excellent specific stiffness and strength. However, incomplete understanding of their failure behaviors leads to composite components often being designed with a high Safety Factor, limiting their advantages. Using computational methods, this project studies carbon fiber-reinforced composite microstructures for the objective of understanding and improving material performances under compression load which is one of the main considerations in primary aerospace structure design. A Finite Element (FE) model for the evaluation of composite compression behaviors was developed, allowing the identification of several key material properties affecting composite performance. The numerical …

Cooperative Rendezvous In Multi-Vehicle Systems, Rajeev Shobhit Voleti

Mechanical and Aerospace Engineering Dissertations

The field of cooperative, multi-vehicle systems has witnessed a significant expansion and evolution, yielding considerable opportunities for improved autonomy, resilience, and robustness. Despite these promising developments, complex challenges persist in ensuring secure and efficient rendezvous among cooperative peers. The term "rendezvous," within the realm of cooperative control, refers to the simultaneous convergence of multi-vehicle systems to a designated target location. In missile guidance, the problem of multiple pursuer missiles achieving rendezvous with a target is termed as a salvo attack. Current methodologies often grapple with issues related to synchronization, high latency and network security, all of which can adversely impact …

Hitch Cart “Landing Gear”, Rebekah White, Jose Raygoza, Randy Hernandez, Brandon Leon

Mechanical Engineering

This report aims to allow our sponsor, to review our design process of the Hitch Cart Landing Gear Prototype. In the design overview section of this report, we discuss the primary design modifications we made to the wheel mechanism of the existing hitch cart prototype, including the addition of the ACME screws and the folding brackets. This allows our sponsor to see the intended improvements made to the past prototype and understand the primary goal of our project. Then, in the implementation section, we cover the entire manufacturing process to allow our sponsor to understand what manufacturing steps must be …

Utilizing Bayesian Optimization In Technoeconomic Analyses For Integrated Energy Systems, Anthoney Griffith

All Graduate Theses and Dissertations, Fall 2023 to Present

Technoeconomic analysis is a key element in the study of integrated energy systems. The goal of this analysis is the sizing of technologies resulting in the best economic outcome for the system. The evaluation of this system involves sizing the components and simulating the resulting market to determine an outcome. This simulation incorporates multiple possible values of uncertain parameters like grid price and wind generation. This problem is currently approached with the gradient descent optimization method. An alternative approach, Bayesian optimization, sees success on simple problems of a similar nature to technoeconomic analyses. These results motivate applying Bayesian optimization as …

Capstone Review: Filament Unit Multiplexing Engine, Gal Cohen

University Honors Theses

The Filament Unit Multiplexing Engine (FUME) is a Mechanical Engineering capstone project sponsored by Portland State University's Electronic Prototyping Lab (EPL). The project addresses the need for an automated system to manage 3D printing operations. The current manual process of selecting and routing a spool of filament to one of the available 3D printers is labor-intensive and limits the efficiency of the lab’s 3D printing farm. FUME aims to create a custom solution tailored for a multi-user, multi-spool, and multi-printer environment. The designed system includes key components: a spool holder, an engine, a track and shuttle system, and a funnel. …

Shape Memory Alloy Capsule Micropump For Drug Delivery Applications, Youssef Mohamed Kotb

Theses and Dissertations

Implantable drug delivery devices have many benefits over traditional drug administration techniques and have attracted a lot of attention in recent years. By delivering the medication directly to the tissue, they enable the use of larger localized concentrations, enhancing the efficacy of the treatment. Passive-release drug delivery systems, one of the various ways to provide medication, are great inventions. However, they cannot dispense the medication on demand since they are nonprogrammable. Therefore, active actuators are more advantageous in delivery applications. Smart material actuators, however, have greatly increased in popularity for manufacturing wearable and implantable micropumps due to their high energy …

Enhancing Miter Saw Safety: Challenges And Prospects Of Brake Incorporation With An Automatic Blade Retraction System, Derek S. Cole

University Honors Theses

Miter saws pose significant safety risks with thousands of injuries reported annually. Despite this risk, they are still used every day as they are a necessity for thousands of workers in the United States and globally. This leaves a demand to make these machines safer to mitigate any potential harm. This research addresses the critical need for an automatic safety system for miter saws, aiming to enhance user safety by retracting and stopping the blade upon skin contact. This analysis identified the primary challenge: The large force generated when braking at high speed on a miter saw blade, translates the …

Barcode Medication Administration (Bmca): 2023-24, Krishan R. Patel, Carlos E. Sosa, Mary Grace Sy

Industrial and Manufacturing Engineering

The Barcode Medication Administration is an important system implemented within a hospital. It is the process in which nurses and other healthcare professionals prescribe and distribute medication to the patients. It aids in organizing which patient got prescribed which medication from which doctor and provides records on who was given care by who. The whole BCMA system is a multi-step process from getting the medication prescribed, to the nurses having to pick up the medication from the medication cabinet, and then having to scan the patient and the medication to finally administer medications.

The current BCMA system implemented at the …

Impact Of Student Beliefs And Self-Efficacy On Performance In Higher Education Stem Courses, Lauren Nicole Fogg

Doctoral Dissertations

In engineering education, students often face feelings of inadequacy, leading to academic struggles and potential dropout. This dissertation investigates the impact of interactive course materials on students' confidence and self-efficacy in problem-solving, focusing on an Engineering Materials class at Louisiana Tech University. Over four quarters, involving seven sections and 218 students, a 13-question Likert scale survey was administered repeatedly, alongside demographic data and textbook usage surveys. The study aims to compare students’ attitudes and beliefs when not using a textbook versus when using an interactive web-native book. Hypotheses suggest that the interactive book will enhance problem-solving beliefs, confidence, and grades. …

Redesign Of Leg Assembly For Remote Walking Training Device To Improve Gait Kinematics, Jacob Anthony

Mechanical Engineering Theses

As modern medicine has improved, the average age of patients has increased. This has cause a growing number of patients to develop disabilities over time due to spinal cord injuries and stroke among other neurological ailments. This has led to an increased interest in developing robotic exoskeletons to help patients with neuromuscular rehabilitation. However, most exoskeletons do not accurately replicate the natural human gait kinematics due to a lack of degrees of freedom at the designed knee joint. In this thesis, the leg assembly for a robotic rehabilitation (RoboREHAB) device is redesigned to improve the gait kinematics and a reinforcement …

Recovery Of Cyber Manufacturing Systems From False Data Injection Attacks On Sensors By Reinforcement Learning, Romesh Prasad

Dissertations - ALL

Cyber-manufacturing systems (CMS) represent the future design vision for manufacturing systems, aiming to enhance product quality, and productivity, and reduce downtime. The third industrial revolution was driven by computer systems and automation, while the fourth industrial revolution was inspired by the internet, network, and connectivity. However, this integration also introduces vulnerabilities, particularly through false data injection attacks on sensors. Sensors play a pivotal role in the automation framework of manufacturing systems spanning five levels: process, operational, supervisory, plant, and enterprise. Sensors are instrumental in communicating information from the process level to the enterprise level. It also enables controllers at the …

Analyzing Heat Generated From Electro-Osmotic Flow Utilizing Computational Fluid Dynamics, Jordan Elizabeth Grothe

Honors Thesis

Without extensive vascularization, the transfer of fluid and nutrients through human tissue is limited to diffusion and weak interstitial flow. Electroosmosis, or the flow of fluid driven by an electrical field, has become a promising solution. Scientists have begun applying electricity to human tissue to promote stronger interstitial flow; however, optimization of this process has proven to be a challenge due to ohmic heating. Cells function within a small range of temperatures and exposure to voltages exceeding the threshold will cause cells to degrade and die prematurely. This research seeks to better understand and quantify the range of voltage where …

Application Of Biochar / Bentonite Based Admixtures In Reinforced Concrete For Corrosion Prevention, Jacob Fleury

Graduate Theses & Non-Theses

Reinforced concrete systems are in many sectors of infrastructure. Due to a combination of elevated compressive strength from the cement and aggregates and tensile strength from the reinforcing steel, reinforced systems are favorable in construction applications where high strength is desired. However, while reinforced concrete is in service, it can be introduced to contaminants that cause corrosion. Contaminants can leach through the porous matrix of the concrete structure and influence initiation of corrosion products on reinforcement. Corrosion is the primary cause for advanced deterioration of concrete structures. Concrete deterioration has promoted research efforts for the protection of future systems. This …

An Analysis Of Primary Stability Of Stemless Humeral Implants In Shoulder Arthroplasty, David Cunningham

Electronic Thesis and Dissertation Repository

There is a scarcity of literature on the performance of the stemless humeral components. This present work describes the development of a novel loading simulator for the quantification of implant performance, as well as its use in the evaluation of implant parametric design and surgical protocol decision variables.

Interface fixation of humeral components was first evaluated using computational methods to determine the optimal metric to quantify implant fixation. Distractive micromotion was found to be the defining micromotion direction in two different designs of humeral implants.

A loading simulator capable of replicating 3D physiological loads, and comprehensive loading and digital image …

Study Of Accidental Sliding-Mode Control, April Mary Miller

Theses and Dissertations

The objective of this paper is to examine the Quanser SRV-02 motor servo for the presence of an accidental sliding mode. The SRV-02 is used by undergraduate students to learn basic concepts in controls engineering and will display unexpected sliding mode behavior when its in the “out of box” configuration. To gain a strong background understanding in characteristics of sliding mode, a review of literature on sliding-mode control and sliding mode behavior is completed. Next, a theoretical analysis of the SRV-02 motor servo during the sliding mode is developed. An effort is made to find a Lyapunov function that proves …

Validating The Design Tensile Strength Of Grade 5 And Metric Class 8.8 Bolts, Paxton Charles Lifsey

Masters Theses

Bolted connections offer many benefits including ease of installation and maintenance and replaceable components, but must have sufficient strength in order to take advantage of these benefits. One of the major ways a bolted connection is loaded is under tension. In this loading condition, bolted connections can fail via tension in the threaded area, shear in the bolt threads, or shear in the nut threads. Standards such as FED-STD-H28/2B and ISO TR/16224 include equations for the stress area and strength of these limit states as well as for the required length of engagement such that tensile failure controls. These equations …

A Framework For Estimating Hybrid Manufacturing Costs, Nathan Joel Wilson

Masters Theses

Based on its potential to reduce lead times, hybrid manufacturing, which often includes both additive manufacturing and machining processes, is receiving more attention from manufacturers as they seek to increase their supply chain resilience and efficiency. A new solid-state additive manufacturing method, referred to as additive friction stir deposition (AFSD), has shown the potential to become an important process for hybrid manufacturing. To justify the selection of a hybrid manufacturing approach, the cost needs to be estimated for comparison to conventional approaches. This thesis proposes a suite of cost models that include AFSD, powder bed fusion (PBF), wire arc additive …

Deep Reinforcement Learning Of Variable Impedance Control For Object-Picking Tasks, Akshit Lunia

All Theses

The increasing deployment of robots in industries with varying tasks has accelerated the development of various control frameworks, enabling robots to replace humans in repetitive, exhaustive, and hazardous jobs. One critical aspect is the robots' interaction with their environment, particularly in unknown object-picking tasks, which involve intricate object weight estimations and calculations when lifting objects. In this study, a unique control framework is proposed to modulate the force exerted by a manipulator for lifting an unknown object, eliminating the need for feedback from a force/torque sensor. The framework utilizes a variable impedance controller to generate the required force, and an …

Digital Twin In Military Ground Vehicles: Design And Predictive Maintenance, Conner W. Eddy

All Theses

Digital twin technology builds upon virtual engineering models, computer simulation, and real-time field data streaming to enable next-generation designs and predictive maintenance. A digital twin is a computer-based high-fidelity collection of models that predicts the performance of dynamic systems per operating cycles, input feature parameters, and data communication from a physical plant. Product Lifecycle Management (PLM) is growing in importance and is central to virtual design processes where the digital twin toolset fits into this emerging architecture. The product design process can be advanced using digital twin resources by eliminating the need for, and cost from, continual physical prototyping, reliability …

Improved Ballistic Impact Resistance Of Nanofibrillar Cellulose Films With Discontinuous Fibrous Bouligand Architecture, Colby Caviness

All Theses

Natural protective materials offer unparalleled solutions for impact-resistant material designs that are simultaneously lightweight, strong, and tough. Particularly, the dactyl club of mantis shrimp features chitin nanofibrils organized in a Bouligand structure, which has been shown to effectively dissipate high-impact energy during powerful strikes. The mollusk shells also achieve excellent mechanical strength, toughness, and impact resistance with a staggered, layer-by-layer structure. Previous studies have shown that hybrid designs, by combining different bioinspired microstructures, can lead to enhanced mechanical strength and energy dissipation capabilities. Nevertheless, it remains unknown whether combining Bouligand and staggered structures in nanofibrillar cellulose (NFC) films, forming a …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Large Eddy Simulation Of Fluid Mixing In Migadome Facility For The Astfe Nuclear Thermal Hydraulics Cfd Competition, Kolten Strauss

Mechanical Engineering Undergraduate Honors Theses

This paper is a documentation of a submission to the First Annual ASTFE Nuclear Thermal Hydraulics Computational Fluid Dynamics (CFD) Competition [1]. To validate simulations of turbulent mixing in buoyancy-driven flows, an air and argon test case was set up inside the University of Michigan’s MiGaDome mixing vessel. This submission to the competition used a polyhedral mesh of about two and a half hundred thousand cells, a Large Eddy Simulation (LES) of the MiGaDome, and the Wall-Adapting Local Eddy-viscosity (WALE) subgrid approximation model. The competition included a factor considering the energy cost of our simulations, so it was decided to …

Flow Characterization With Acoustic Emission Sensing, Jackson Marsh

Mechanical Engineering Undergraduate Honors Theses

Acoustic emissions (AE) allow for non-intrusive sensing into many types of systems. In systems where there is flow of some type, AE is very useful as these types of systems can be characterized in many ways from the collisions or creation of the flow. Correctly setting up the AE system is extremely important. Failure to do so results in imprecision and inaccurate data being collected. Because of this synchronization techniques, sensor configurations, and data acquisition systems must all align. This can be done with off-the-shelf, commercial systems, but this does not allow for customization and the ability to tailor the …

Model-Based Comparison Of Biological Organism And Electro-Mechanical System Resiliency Strategies, Nicholas Ratycz

Mechanical Engineering Undergraduate Honors Theses

Bio-inspired design has been used by many engineers to solve difficult problems or to make manufacturing processes more efficient. Biomimetics is the study of implementing the structure or function of biological substances, materials, mechanisms, and processes onto artificial ones that mimic the original. The goal of the BIASD tool is to provide bio-inspiration for engineers by studying the fault-adaptive strategies that biological systems use, rather than just their structure or function. In this thesis, the fault adaptive strategies of both a biological example and that of a real cubesat are compared using three types of model-based system diagrams to show …

Cam And Design For Manufacturing: Developing A Project-Based Learning Course, Stephen Pierson

Mechanical Engineering Undergraduate Honors Theses

To effectively serve student career success, mechanical engineering programs must teach students how to account for manufacturing considerations in design. Despite this, manufacturing education is a glaring area of need in current engineering curricula. In fact, basic manufacturing knowledge is one of the only hard skills consistently ranked as one of the greatest weaknesses of mechanical engineering hires in surveys of industrial employers over the last few decades. Without radically changing departmental curriculum to include more emphasis on design-build projects, one solution to combat this is to incubate a lab course in mechanical engineering programs in which undergraduates would practice …

Mechanical Properties And Microstructure Of Multi-Materials Fabricated Through A Combination Of Lpbf And Ded Additive Manufacturing Techniques, Christopher J. Bettencourt

All Graduate Theses and Dissertations, Fall 2023 to Present

This research explores the use of different metals combined through 3D-printing to enhance the performance of materials, with a focus on making heat exchangers more cost-effective for renewable energy. The goal is to replace a costly high-temperature alloy with a more affordable low-temperature alloy, using metal additive manufacturing for its benefits such as less material waste, faster production, reduced weight, and the ability to print entire assemblies in one go. The study delves into a unique combination of two 3D-printing techniques, Directed Energy Deposition and Laser Powder-Bed Fusion, to create a multi-material composed of stainless steel 316L and a nickel-based …