Multiobjective Optimal Design Of Hierarchical Control Architectures For Quadcopter Systems: Linear And Hybrid Approaches, Xinhuang Wu

Theses, Dissertations and Capstones

This thesis investigates the design of many-objective optimal controllers for quadcopter unmanned aerial vehicles (UAVs), focusing on both linear and hybrid control structures. In Chapter 2, a multi-input–multi-output (MIMO) optimal control system is developed for a six-degree-of-freedom UAV actuated by four brushless DC motors. The UAV dynamics are first derived and linearized around an operating point, and then organized into a three-loop nested control structure. The outer loop computes the roll and pitch angles required to maneuver the vehicle in the global X and Y directions, the middle loop regulates attitude and altitude, and the inner loop controls the angular …

Improving The Reliability Of Parts Produced Via Laser Powder Bed Fusion Through A Data-Driven Geometry Optimization Methodology, Federico Venturi

Mechanical and Aerospace Engineering Dissertations - Archive

This research aims to qualify the effect of design geometry on quality metrics of additively manufactured (AM) components that define reliability. Through the use of a novel methodology to characterize these quality metrics, AM components are inspected for the presence of defects such as surface roughness notches and porosity. These directly hinder the high-cycle fatigue characteristics demonstrated through the Kitagawa-Takahashi diagram and the El-Haddad model. By demonstrating the effect of geometry through a designed experiment and the adoption of the Murakami square root area parameter and Arola-Ramulu model, the improvement to fatigue life can be quantified. Incorporating this data into …

Stress Analysis Of Anisotropic Inclusion Problems Using Complex Variables, Liming Chen

Mechanical and Aerospace Engineering Dissertations - Archive

This research presents an analytical framework for determining stress fields in an elastic medium containing a circular anisotropic inclusion embedded in an infinitely extended isotropic matrix subjected to far-field uniform stresses. Stress distributions within both the inclusion and the matrix are described using classical stress functions, widely employed in two-dimensional elasticity theory.

To manage the complexity of the mathematical derivations, symbolic computation software (Mathematica) is used to streamline the analysis and obtain closed-form solutions. This approach overcomes traditional computational barriers that have limited the practical application of complex variable methods (CVM) in elasticity.

The methodology builds upon the foundational work …

Design Strategy For Hybrid Thrust Air Bearings: Comparative Analysis Of Rigid Vs. Foil Bearings Considering Optimum Taper Angle And Orifice Location With Experimental Validation, Ehiremen Ebewele

Mechanical and Aerospace Engineering Dissertations - Archive

Gas foil thrust bearings (GFTBs) are contactless bearings that offer advantages such as lightweight construction and the ability to accommodate misalignments and geometric irregularities. However, their load capacity is lower than rigid or magnetic bearings. The structure and geometry of the foil significantly influence GFTB performance. The taper-flat design is the most used configuration due to its effectiveness and ease of implementation. Key parameters in designing this geometry include taper ratio, taper height, orifice size, and orifice location. These parameters must be optimized alongside manufacturing constraints to produce an effective GFTB. This study presents a design optimization investigation of various …

Experimental And Numerical Modelling-Based Optimization Of Additive Manufacturing Processes, Vishnu V. Ganesan

Mechanical and Aerospace Engineering Dissertations - Archive

ABSTRACT

Experimental and Numerical Modeling-Based Optimization of Additive Manufacturing Processes

Vishnu V Ganesan, Ph.D.

The University of Texas at Arlington, 2025

Supervising Professor: Dr. Ankur Jain

Experimental and numerical modeling play a pivotal role in advancing additive manufacturing technologies by enabling a deeper understanding of complex, multi-physics processes that govern part quality, performance, and reliability. These manufacturing techniques—ranging from Powder Bed Fusion (PBF) and Material Extrusion (MEX) to Automated Fiber Placement (AFP)—involve tightly coupled thermal, mechanical, and material phenomena that are challenging to capture through empirical observation alone. Experimental methods offer critical validation and insights into real-world behavior, while numerical …

Intelligent Microfluidic Systems For Precision Manipulation And Real-Time Recognition Via Dielectrophoresis And Deep Learning, Negar Danesh

Mechanical and Aerospace Engineering Dissertations - Archive

This dissertation introduces intelligent microfluidic platforms by combining advanced DEP-based manipulation with real-time visual feedback. A DEP device featuring circular corral traps and dual-plane electrodes enables precise submicron particle trapping, high-resolution particle separation, and cell-particle co-assembly. Simulations and experiments confirm enhanced electric field control and stable confinement. To enable adaptive operation in EWOD systems, a deep learning model (U-Net) was developed for real-time droplet meniscus segmentation. The model achieved 98% accuracy and remained robust under noisy, low-contrast conditions. A live video pipeline was implemented, enabling consistent frame-by-frame feedback for closed-loop control. Together, these innovations establish a foundation for autonomous, high-performance …

Nonlinear Bump Stiffness Model And Its Effect On Structural Stiffness And Nonlinear Rotordynamic Characteristic Of Foil Bearing, Woongeon Lee

Mechanical and Aerospace Engineering Dissertations - Archive

Bump foils are the most widely used in foil bearings, but the behaviors of bump foils are complicated, and their characteristics have been a focus of research for decades. Bump foils are usually modeled as stiffness and damping are accounted for through interactions with shaft eccentricity, loading, shaft speed and excitation frequency. These nonlinear characteristics of the bump foil of radial foil bearings can be observed during both manufacturing and operational processes because of their inherent structural properties such as bump geometry, forming process, age-hardening process and complicated contact behavior with bearing housing. These nonlinear characteristics are one of the …

Multi-Objective Design Optimization Of Hypoid Geared Rotor Systems, Xinqi Wei

Mechanical and Aerospace Engineering Dissertations - Archive

Hypoid gears represent one of the most generalized and complex forms of gearing, widely used for power transmission of skew shafts in vehicles, aviation, and marine transmission applications. Optimizing their performance remains challenging due to the complex tooth surface and contact behavior. Specifically, the design parameters of the tooth surface are multi-scale, interdependent, and subject to strong constraints, leading to strong nonlinearity and an ill-conditioned Jacobian matrix in the parameter identification model. Moreover, feasible and insensitive contact conditions are difficult to constrain due to the inherent complexity of local conjugate contact between the meshing surfaces. These challenges significantly increase optimization …

Deep Neural Network Models For Heatsink Performance Prediction And Optimization In Single Phase Immersion Cooling: Framework For Future Design Tools And Digital Twin Integration, Braxton J. Smith

Mechanical and Aerospace Engineering Theses - Archive

The rapidly rising computational power of modern computing components combined with the advanced packaging techniques being implemented has resulted in exponentially increasing thermal design powers (TDP) from CPUs and GPUs. Traditional air-cooling methods are approaching their effective cooling limits for many of these components, requiring lower supply air temperatures, higher supply air flowrates, and much larger heatsinks to remain feasible. Transitioning from air-cooling to single-phase immersion cooling offers numerous benefits in thermal performance, data-center size reduction, and energy efficiency. To leverage the merits of immersion cooling, the performance of a given heatsink must be predicted and optimized for best performance …

Study On Motion Prediction Analysis Of Large Vessels Entering Kaohsiung Port Second Harbor, Li-Heng Cheng, Hsing-Yu Wang

Journal of Marine Science and Technology–Taiwan

Pilotage is a primary service offered by ports, ensuring the safe passage of entering and exiting vessels. This study applied motion prediction analysis to large vessels navigating the constrained waterways of Kaohsiung Port’s second harbor. To address the needs of pilots and port operators, a simplified planar motion equation was developed that incorporated speed over ground and rate of turn (ROT) as primary variables. The model relied on inputs of limited navigational data, enabling pilots to predict changes in heading and position over time and determine the conditions for safe harbor entry. Vessel paths and turning angles were analyzed to …

Materials Reliability In Direct-To-Chip Cooling: A Systematic Study Of Aluminum Corrosion In Next-Generation Data Center Coolants, Fnu Harish Gangadhara

Mechanical and Aerospace Engineering Theses - Archive

Data centers are rapidly scaling to support artificial intelligence, cloud platforms, and other high-performance workloads, driving a sharp increase in chip and rack power densities that are now approaching, and in some cases surpassing, 50–100 kW per rack. In response, direct-to-chip liquid cooling has become a key enabling technology for managing these extreme thermal loads, yet the durability of materials in contact with the coolant remains a major reliability concern over system lifetimes. Copper has traditionally been used for cold plates and cooling-loop components, but its relatively high cost, mass, and supply-chain uncertainty are motivating a shift toward aluminum as …

Development Of A Design Tool For Tow-Steered Composite Structures With Machine Learning-Assisted Modeling, Bangde Liu

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Fiber-reinforced composites (FRCs) are widely used in aerospace, automotive, and other engineering applications due to their lightweight characteristics and superior mechanical properties. Traditional FRCs employ a fixed fiber orientation in each layer, and while different layup sequences can tailor performance, the mechanical properties remain spatially uniform. Tow-steered composites, which enable fibers to follow curvilinear paths, offer the potential for spatially varying stiffness and strength, improving structural performance.

This dissertation addresses key challenges in modeling and designing tow-steered composite structures, including the lack of commercial design tools, the high computational cost of design optimization, and the need to efficiently evaluate manufacturing …

Evaluation Of The Maneuverability Of An 85m Fishing Trawler (Focusing On Dynamic Stability), Chun-Ki Lee, Su-Hyung Kim

Journal of Marine Science and Technology–Taiwan

Most fishing vessels are less than 100 meters in length, so IMO maneuverability standards do not apply. As a result, studies on the maneuverability of fishing vessels are considerably fewer compared to those on merchant ships. However, with technological advancements, the size of fishing vessels continues to grow, and as more fishermen are on board, accidents could lead to fatal casualties. In response, the authors determined that research on the maneuverability of fishing vessels is urgently needed. Thus, the authors conducted a maneuverability evaluation on a fisheries training vessel with the hull shape of a fishing trawler, 85 meters in …

A Hybrid Image Filtering Approach For Improving Edge Detection Of Riverbed Particles With Complex Textures, Po-Wei Lin, Hsun-Chuan Chan

Journal of Marine Science and Technology–Taiwan

The distribution of particle size in gravel-bed rivers affects the flow condition, sediment transport, and river morphology. However, conventional particle size analysis is laborious and time-consuming. To enhance the efficiency of particle size analysis, image-based methods have been widely explored, but complex particle textures increase the difficulty in identifying particle edges during image analysis. This study develops a filtering approach based on the rolling guidance filter and leverages the differences in grayscale gradients between particle edges and textures to design a guidance image tailored for the rolling guidance filter. This design enables the filter to preserve particle edges while smoothing …

Comparison Of Canopy Materials To Improve The Performance Of Sea Anchors Used For Fishing Operations, Namgu Kim, Su-Hyung Kim, Yoo-Won Lee, Kyung-Jin Ryu

Journal of Marine Science and Technology–Taiwan

Sea anchors used for fishing operations help improve catch rates by stabilizing vessel drift speeds to match tidal or ocean currents. The underwater resistance experienced by a sea anchor's canopy significantly impacts its performance, yet there has been limited research on canopy materials. This study investigates how different canopy materials can enhance sea anchor performance. Specifically, we tested sea anchors made from three fabrics: the currently used polyamide (PA) material, PA material with increased yarn density in the weft direction, and polyester (PES). Using Korean national standards, we compared the yarn density, weight, water absorption capacity, drying rate, air permeability, …

Research On Ship Track Prediction Based On Ipso-Cnn, Xiangen Bai, Nuo Chen, Xiaofeng Xu

Journal of Marine Science and Technology–Taiwan

With the rapid development of the global economy, international imports and exports have become increasingly important. Timely and effective tracking and prediction of ship trajectories are important in the face of complex maritime traffic. Based on AIS data, this study establishes a ship trajectory prediction model combining improved particle swarm optimization (IPSO) and a convolutional neural network (CNN) that uses the ship's historical navigation trajectory data to predict the future navigation trajectory. The historical ship trajectory data of the Port of Ningbo-Zhoushan were selected for the experiment, and the IPSO-CNN model experiment results were compared with those of other models. …

Fault Tree Analysis For Robust Design, Jonathan Degroff, Gene Jean-Win Hou

Mechanical & Aerospace Engineering Faculty Publications

The objective of this research is to incorporate system failure into a robust design formation and solution process. The system failure referred to here will be built using fault tree analysis (FTA), which will take all lower-level failure events into consideration. Two examples are investigated here. One will directly treat the probabilities of the basis events as design variables, The other will be formulated in five different models: deterministic design optimization, the reliability index-based, the “and” gate-based, the “or” gate-based and the “inhibit” gate-based robust design. Their corresponding optimization solutions will be compared with each other. The post-optimality analysis of …

Polarized Positrons At Ce⁺Baf, A. Ushakov, J. Benesch, M. Bruker, L. Cardman, J. Conway, S. Covrig Dusa, P. Degtiarenko, Y. Enomoto, S. Gessner, P. Ghoshal, S. Gopinath, J. Grames, C. Gulliford, S. Habet, G. Hays, C. Hernández-García, A. Hofler, R. Kazimi, M. Kostin, V. O. Kostroun, F. Lin, V. Lizárraga-Rubio, K. Mahler, Y. Morikawa, S. Nagaitsev, S. Ogur, G. Palacios-Serrano, N. Raut, B. Rimmer, Y. Roblin, A. Seryi, K. Smolenski, M. Stutzman, R. Suleiman, A. Sy, N. Taylor, D. Turner, A. Ushakov, C. Valerio-Lizarraga, E. Voutier, S. Wang, Y. Zhang

Mechanical & Aerospace Engineering Faculty Publications

A baseline concept for a continuous wave (CW) polarized positron injector was developed for the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab [1]. This concept is based on positron beam generation by a high current polarized electron beam (1 mA, 120 MeV, >85% polarization) irradiating a rotating water-cooled tungsten target or liquid metal target. The update on the development of the Ce⁺BAF injector concept including the polarized electron source, the development of high power targets, simulations of positron capture, the design of the transport line from the positron injector to the CEBAF North Linac and the planned experiment …

Deep Learning Approaches For Predicting Strain Energy In Heterogeneous Materials, Junesh Gautam

Electronic Theses and Dissertations

Finite Element Analysis (FEA) faces computational challenges when analyzing nonlinear and heterogeneous materials. Utilizing the Mechanical MNIST dataset, comprising 60,000 simulated samples of 28x28 pixel domains under large deformation, the study evaluates classical regression methods (Linear Regression, Random Forest, Gradient Boosting) and advanced deep learning architectures (Convolutional Neural Networks (CNN) and Residual Networks (ResNet)). CNN models achieved superior performance, with a Mean Squared Error (MSE) of 4.21 and an R2 value of approximately 0.982, outperforming classical regression models and slightly surpassing ResNet architectures. These deep learning methods automatically learn spatial relationships from pixel-based representations, eliminating the need for manual feature …

Nonlinear Dynamics And Control Of An Autonomously Operated Towed System, Brian Allan Carr

Wayne State University Theses

Emergency towing vessels are a vital component of maritime safety. This study works to improve on previous works in the area of automating the towing of disabled ships. In doing so control methods for transient three degree of freedom dynamics of a tug and tow system which is connected with a finite element cable are evaluated. A Heaviside unit step function is inserted to void both the elastic and viscous interaction between the massive elements whenever the distance between two neighboring masses appears to be below the corresponding undeformed distance. This follows the representation of the cable as a one-dimensional …

The Design Of A Bioinspired Impact Mitigation System Towards The Prevention Of Brain Injuries, Bryce H. Reimer

Master’s Theses

Traumatic brain injuries (TBIs), including concussions and chronic traumatic encephalopathy (CTE), remain a major concern across contact sports, military operations, and transportation. Despite advancements in protective equipment, current strategies often fall short in preventing the mechanical conditions that contribute to long-term neurological damage. This thesis presents the design and validation of a bioinspired impact mitigation system modeled after bighorn sheep horn structures, which have evolved to endure high-energy collisions without apparent brain injury.

Using biomimetic principles, the research integrates experimental and computational methods to evaluate how horn-like geometries reduce impact-induced accelerations. A custom drop tower was built to test dynamic …

Nebraska Summary #1293: Fendt 618 Vario, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

In‑Situ Characterization And Modeling Of Machining‑Induced Residual Stresses In Peripheral Milling Of Ti–6al–4v With Rounded Cutting Edges, Matthias Wimmer, Julius M. Schoop, Michael F. Zaeh

Mechanical Engineering Faculty Publications

The residual stress state in the sub-surface of machined components can significantly impact the properties and performance of parts, such as tribological properties, fatigue life, and dimensional distortion. The evolution of residual stresses depends on the selected process parameters and tool geometry, which affect the thermo-mechanical load imposed on the workpiece. The cutting-edge radius is among the most important factors influencing the resulting residual stresses. In this paper, a semi-analytical model for the determination of residual stresses after peripheral milling of Ti–6Al–4V is presented. It considers the physical principles of orthogonal machining, including the complex geometric and kinematic relationships during …

Transient Thermal Finite Element Simulation For Process Modeling In Wire Arc Additive Manufacturing, Satya Sai Kumar Pilli

Dissertations, Master's Theses and Master's Reports

This thesis presents the development of a transient thermal framework for Wire Arc Additive Manufacturing (WAAM) created using ANSYS Workbench. This study aims to understand the inherent properties and thermal behavior of WAAM by using the Finite Element (FE) simulation technique to reduce the need for experiments. Specifically, the transient thermal WAAM simulation framework uses the heat source Goldak model to understand the thermal behavior for a given voltage, initial temperature, and travel speed during the process to predict process temperature. The outcomes of this thesis aim to significantly decrease material waste and repetitive experiments and accelerate production process design …

Actuator Disk Model For Aeropropulsive Coupling Effects In Vortex Particle Method, Eduardo Alvarez, Vineet Ahuja, Vinod Lakshminarayan, Aaron Perry, Ryan Anderson, Andrew Ning

Faculty Publications

Blown lift and distributed electric propulsion aircraft pose strong aeropropulsive coupling effects that cannot be ignored during the early stages of design. In this study, we develop an advanced actuator disk model (ADM) for aeropropulsive coupling effects of ducted fans with the vortex particle method (VPM). The advanced ADM consists of (1) an actuator disk at the rotor plane, (2) a surface vortex sheet modeling the mixing and convection of blade tip vorticity along walls, and (3) a powered wake at the exhaust. With these three components, a propulsion jet with an arbitrary velocity profile is formed and interactions with …

Comparing The Sensitivity And Specificity Of Novel Motor Assessments For Traumatic Brain Injury, Paula K. Johnson, Ariana M. Hedges-Muncy, Erin D. Bigler, Lorie Richards, Steven Knight Charles

Faculty Publications

Background: Portable technology that records movements with high accuracy provides potential for sensitive clinical movement tests for individuals who experienced a traumatic brain injury (TBI). Objective: (1)To present impairments assessed using markerless motion capture (MMC) and (2) to compare the sensitivity and specificity of the MMCmediated tests to each other and to common clinical tests. Design: Screening study, using as criterion standard the ability to classify participant with TBI versus control participant. Setting: Research laboratory. Participants: The study included 30 individuals with TBI and 101 control participants. Entry criteria included most recent head injury < 5 years old, no history of movement issues prior to injury, no movement-affecting medications, and sufficient cognitive ability to follow instructions. Interventions: Not applicable. Main Outcome Measures: Performance on MMC-mediated tests and existing clinical analogs. MMC-mediated tests included finger oscillation, simple reaction time, and visually guided movement tasks. For comparison, participants also completed the following clinical tests: Halstead–Reitan finger tapping, simple reaction time test, and Beery Visuomotor Integration test. Impairments were identified as test scores of participants with TBI that fell outside of the 95% interval of control participants’ test scores. Random forest analysis was used to calculate the sensitivity and specificity of MMC and clinical tests according to their ability to correctly classify participants with TBI and control participants. Results: MMC-mediated tests revealed impairments in more participants with TBI than clinical tests in all three TBI groups (mild, repeated, and moderate to severe). Similarly, MMC-mediated tests revealed a higher percentage of scores as impairments than clinical tests in all three groups with TBI. Furthermore, MMC-mediated tests proved more sensitive and more specific than clinical tests (70% versus 50% and 98% versus 93%, respectively). Conclusion: MMC-mediated tests are sensitive and specific (compared to traditional clinical tests) and have potential to fill a gap in clinical care of TBI.

Development Of A Compliant Soft Gripper With Embedded Force Sensors, Ayman Abbas, Abdelrahman Said, Tamer Kahlil, Mahmoud Magdy

Mechanical Engineering

Robotic manipulators have the capability to perform repetitive tasks with a level of efficiency and precision that exceeds the capabilities of human operators. Currently, they are commonly found and extensively utilized across various disciplines. However, robotic manipulators have gradually begun to make inroads into fields beyond manufacturing, such as medicine and agriculture. Due to the diverse range of industries utilizing robotic manipulators, the nature of tasks assigned to these devices can often be more intricate and multifaceted than conventional assignments. Hence, conventional mechanical grippers may not always be suitable, prompting a growing need for grippers capable of adapting to effectively …

Design And Implementation Of Smart Automation For Sustainable Plastic Recycling With Iot Integration, Mostafa Abdelaziz, Mahmoud Khedr, Amr Bakkar, Yossef Zidan, Abdelrahman Youssef, Mahmoud Magdy

Mechanical Engineering

Plastic pollution poses a critical environmental challenge, infiltrating ecosystems and impacting human health. One innovative solution involves repurposing recycled plastics into interlocking blocks as a sustainable alternative to concrete in construction. However, manual production methods hinder scalability, efficiency, and product consistency while generating material waste. This research addresses these limitations by automating the production process using PLC and IoT technologies. The findings demonstrate that automation significantly enhances production rates, ensures consistent quality, and minimizes waste, thereby improving operational efficiency and environmental sustainability. IoT is integrated to enhance the system's capabilities by providing real-time connectivity and data exchange. The IoT dashboard, …

Ai-Driven Robotic System For Predictive Maintenance: Urban Road Defect Detection In Smart Cities, Mostafa Abdelaziz, Mahmoud Khedr

Mechanical Engineering

This paper presents the development and evaluation of an integrated AI & robotic solution for predictive maintenance in smart cities, focusing on urban road defect detection. The proposed system integrates a mobile robot equipped with a high-resolution camera and a GPS module to capture video footage and geolocation data of road surfaces. The collected data is processed using cloud-based AI models, with YOLOv9 and Roboflow 3.0 Object Detection (Fast) identified as the most effective for analyzing footage to detect cracks and potholes. Experimental results validate the system's ability to accurately identify defects and generate timely reports for maintenance teams. While …

Pre-Programmable Directional Stiffness In Continuum Robotic Arms: Effects Of Truss Configurations, Mostafa Abdelaziz, Zahy Elgendy, Mahmoud Magdy

Mechanical Engineering

This paper investigates the implementation of trussed designs in modular tendon-driven continuum arms (CAs) to address stiffness and stability limitations while maintaining adaptability. Various truss configurations— Single-Level, Combined-Level, and Alternated trusses—were analyzed using Finite Element Analysis (FEA) to evaluate their impact on flexural and axial stiffness under realistic loading conditions. Results demonstrate that truss placement significantly influences performance, with bottom-level trusses improving flexural stiffness by up to 33%, middle-level trusses enhancing axial stiffness by 43%. Further, Combined-Level configurations provide superior overall stiffness, with MiddleBottom trusses achieving a 66.5% improvement in flexural stiffness and a 70.9% increase in axial stiffness, while …