Mechanical Engineering Commons^™

A Computational Approach To Graduated Centrifuge Profiles For Partial Gravity Planetary Environments, Cabell W. Jones

Mechanical & Aerospace Engineering Faculty Publications

Missions such as NASA’s Artemis and SpaceX’s Starship aspire towards creating permanent settlements beyond Earth. In order to achieve this goal, it must be considered that the gravity present on planetary surfaces such as the Moon (0.165 g) and Mars (0.378 g) may be insufficient to support human physiology for long term habitation. On near-Earth missions, issues such as muscular atrophy, neuro-ocular changes, cardiopulmonary variations, and bone mineral density loss have been observed proportional to the duration spent in microgravity. Further studies have suggested that the severity of these conditions scales linearly with decreasing gravity, meaning that astronaut health can …

Atomized Oxidative Polymerization As A 3d Printing Platform For Binder-Free, Bulk Conductive Polymer Architectures, Tazdik Patwary Plateau, Hiep Pham, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Translating the ultrahigh intrinsic conductivity of conjugated polymers into bulk 3D architectures remains a formidable challenge due to the fundamental dichotomy between rheological printability and electronic purity. Existing strategies necessitate a compromise: solution-processing requires insulating binders that degrade charge transport, while binder-free vapor-phase polymerization (VPP) is kinetically confined to surface-limited thin films by diffusion constraints. Here, we introduce atomized oxidative polymerization (AOP), a manufacturing paradigm that overcomes these kinetic barriers via active, layer-by-layer monomer atomization. This approach ensures stoichiometric reaction conditions throughout the printed volume, driving a structural transition toward highly conductive quinoid-dominant chains with enhanced π-π stacking. The resulting …

A Framework For Enhanced Circular Product Development With Total Life Cycle Considerations, Gisele Bortolaz Guedes, Fazleena Badurdeen, Ibrahim S. Jawahir

Mechanical Engineering Faculty Publications

Advancing circular product development (CPD) requires design decisions that account for the entire product life cycle, from material sourcing and manufacturing to use and end-of-use (EoU) stages, to ensure enhanced sustainability performance. Existing Product Development Process (PDP) models tend to emphasize isolated phases or perspectives with limited explicit consideration of the total product life cycle. This hinders the systematic embedding of various Circular Economy (CE) strategies during product development. Thus, designers and engineers lack a unified framework to determine when and where critical decisions should be made to effectively incorporate CE strategies such as effective resource selection, extending product use-life, …

Stoichiometry-Controlled Surface Reconstructions In Epitaxial Abo3 Perovskites For Sustainable Energy Applications, Habib Rostaghi Chalaki, Ebenezer Seesi, Gene Yang, Mohammad El Loubani, Dongkyu Lee

Faculty Publications

ABO₃ perovskite oxides are a versatile class of materials whose surfaces and interfaces play essential roles in sustainable energy technologies, including catalysis, solid oxide fuel and electrolysis cells, thermoelectrics, and energy-relevant oxide electronics. The interplay between point defects and surface reconstructions strongly affects interfacial stability, charge transport, and catalytic activity under operating conditions. This review summarizes recent progress in understanding how oxygen vacancies, cation nonstoichiometry, and electronic defects couple to atomic-scale surface rearrangements in representative perovskite systems. We first revisit Tasker’s classification of ionic surfaces and clarify how defect chemistry provides compensation mechanisms that stabilize otherwise polar or metastable …

Guitar Amplifier Directivity, Rachel C. Edelman, Brian E. Anderson, Samuel D. Bellows, Timothy W. Leishman

Directivity

No abstract provided.

A Unified Finite Element Framework For Cardiac Growth And Remodeling In Mitral Regurgitation Incorporating Fiber Reorientation And Baroreflex, Mohammad Mehri, Jonathan F. Wenk

Mechanical Engineering Faculty Publications

Mitral regurgitation (MR) triggers complex cardiac remodeling responses that alter the structure and function of the left ventricle (LV). While several models have been developed to predict myocardial growth in MR, they often neglect key concurrent adaptive mechanisms that influence both the pattern and severity of LV dilation. This study presents a unified finite element framework to systematically evaluate the individual and combined contributions of fiber reorientation (FR) and baroreflex regulation to LV growth and remodeling, along with the effects of myocardial material property changes associated with the acute and chronic phases of MR. A healthy baseline model and multiple …

Vibration-Based Fault Diagnosis In Industrial Rotating Machinery, Yaman Pandey

All Graduate Theses, Dissertations, and Other Capstone Projects

Unplanned downtime caused by rotating machines results in a significant percentage of the total downtime in manufacturing plants. These downtimes cause significant loss of production time. While preventative maintenance helps minimize lot of these downtimes, it can’t predict the upcoming downtimes and prevent them from occurring. That gave birth to predictive maintenance. While various techniques are used for predictive maintenance, vibration analysis is one of them. In this study, data driven and expert validated diagnosis using vibration analysis for rotary machinery is used. The data is collected from a manufacturing site in Minnesota where 32 rotating assets, including motors and …

Nonlinear Oscillations In Structural Dynamics: Computational Techniques, Data-Driven Tools, And Model Order Reduction, Dalton Stein

Open Access Dissertations

Funding and support for this research was provided by the National Institute for Undersea Vehicle Technology (NIUVT) through the Office of Naval Research (ONR). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.

The content of this dissertation has been removed because it is CUI.

Physics-Constrained Generative Adversarial Networks For Dimensionality Reduction In Optimization, Samuel Sisk, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft make a unique form of urban air mobility due to their low noise, zero emission, and precision control. To maximize efficiency, high-fidelity simulation-based multidisciplinary design optimization discovers the optimal balance among subsystems within an eVTOL. However, conventional multidisciplinary design optimization is computationally intensive due to excessive high-fidelity model evaluations. Moreover, complex nonlinear constraints deteriorate optimization efficiency and convergence. While surrogate models enable efficient design optimization, surrogate modeling suffers in large-scale applications and surrogate-based optimization still has to deal with nonlinear constraints. To address these challenges, the authors' previous work proposed physics-constrained generative adversarial …

Tomo-Piv Study Of Baseline Flow Structures Behind A Strut Injector, Josiah Mcdermott, Connor Bell, Davide Viganò

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Stabilizing combustion in scramjet engines is a formidable challenge due to the small-time scales afforded for air-fuel mixing. Numerous studies in this area have demonstrated the potential of strut-style platforms for fuel injection and mixing enhancement, which remains an active area of research. In the Aerodynamics Research Laboratory at Missouri S&T, a strut-style injector system has recently been installed. In this study, we characterize the baseline flow structures behind this platform absent fuel injection. The wake generated by a strut itself has an appreciable impact on the resulting air-fuel mixing, which motivates its characterization. In future studies, this characterization will …

Optimal Takeoff Trajectory Prediction Of Electric Drones Based On A Fully Automated Optimal Experimental Design Method, Jiachen Wang, Dheeraj Paramkusham, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft is attracting great interest as a viable solution to promote urban aerial mobility with promising flexibility as well as emission reductions. However, the low specific energy of the current battery is still a strong constraint on the range and endurance of eVTOL flights, especially considering the significant power demands during the takeoff process. Engineering design optimization permits promising solutions for the minimum takeoff energy consumption but can be computationally intensive due to iteratively evaluating simulation models. Surrogate-based design optimization is efficient but still relies on optimization iterations which prohibit real-time decision-making. To fill …

Impact Of Dispersed Crystalline Domains On Lithium-Ion Conductivity In Amorphous Li2.99ba0.005ocl Electrolytes, Emmanuel Olugbade, Junquan Ou, Leon Shaw, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Solid-state electrolytes promise safer, high-energy batteries, yet ionic transport is limited by structural heterogeneity and interfacial resistance. We combine hydrothermal synthesis and molecular dynamics (MD) to determine how dispersed crystallinity and interfacial orientation govern lithium-ion conduction in barium-doped anti-perovskite Li_2.99Ba_0.005OCl. Structural and thermal analyses identify a largely amorphous matrix with embedded nano crystallites, and MD captures the same short-range order and dispersion seen experimentally. Electrochemical impedance spectroscopy separates high amorphous-phase conductivity from a pellet-scale response dominated by interfacial limitations, consistent with direct-current polarization. Cyclic voltammetry indicates a broad electrochemical stability window. We quantify transport in crystalline …

Multiphysics Modeling Of Melt Pool Dynamics And Powder Bed Stability In Lpbf Of Inconel 718 For A Circular Cavity, Nayan Pundhir, Oluwapelumi O. Adejumo, Kumbla Chandrashekhara, Joseph W. Newkirk, Heath Misak, Cesar Ortiz Rios

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a metal additive manufacturing process in which a concentrated laser beam selectively melts successive powder layers to fabricate components. Final part quality is highly sensitive to process parameters such as hatch spacing, powder bed density, laser power, and scanning speed. In this study, a computational fluid dynamics model employing discrete element method has been developed in FLOW-3D to simulate LPBF of Inconel 718. The modeled powder bed incorporates particle size distribution data obtained from scanning electron microscopy and is evaluated for single-layer, single-track deposition over a circular cavity. The model captured melt pool dynamics …

Distributed Vibration Sensing For Identification Of Loose Connectors In Coaxial Data Transmission Lines, Saidanvar Esanjonovich Valiev, Anthony C. Okafor, Jeremiah J. Rittenhouse, Jie Huang, Daniel S. Stutts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This study investigates the effect of vibration-induced loose connections on signal reflection (S11) for loose connection identification in aerospace coaxial cables using distributed sensing approach, which is effective in filtering the noise and identifying minor discontinuities. In this approach, a sliding gated window is applied to S11 signal, a fast Fourier transform is performed over the gated windows, cross-correlation is computed between the baseline and vibration-affected signals, and the standard deviation is mapped along the cable length. Sinewave signals from 9 kHz to 5 GHz were swept through cables with vibrating connectors under three conditions: fully tightened, loosened by 180°, …

Nonlinear Control Of A Ciws-Style 2-Dof Turret, Ryan Baur, Ethan Wang, Nilay Kant

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper develops and compares multiple control strategies for a two-degree-of-freedom CIWS (Close-In Weapon System)-style turret tracking rapidly maneuvering airborne targets. A simplified nonlinear manipulator model with realistic actuator torque limits is used as the plant. Five controllers are implemented: a baseline PID (Proportional-Integral-Derivative) controller, a feedforward PID, a Kalman-filter-assisted PID, and two feedback-linearized designs using PID and LQR (Linear-Quadratic-Regulator)-based surrogate dynamics. Controller performance is evaluated on increasingly aggressive three-dimensional target trajectories under varying sensor noise. Results show that PID-family controllers achieve competitive tracking accuracy while remaining torque-efficient and largely unsaturated. Feedback-linearized controllers improve tracking accuracy only when sufficient actuator …

Design, Construction, And Initial Testing Of A Oxy-Acetylene Testing Facility, Blake Bowman, Davide Viganò

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Thermal Protection Systems (TPS) are critical for atmospheric re-entry and hypersonic flight vehicles, yet ground-based evaluation of TPS materials remains challenging due to the cost, complexity, and limited availability of large arc-jet and inductively coupled plasma (ICP) facilities. Oxy-acetylene testing provides a low-cost and accessible alternative for preliminary material screening, sensor development, and fundamental studies of material response under high heat-flux conditions. This paper presents the design, construction, and initial validation of the High-Enthalpy Acetylene Testing (HEAT) facility at Missouri University of Science and Technology. The facility incorporates a modular experimental architecture, independently controlled oxygen and acetylene mass-flow systems, and …

Tomo-Piv Study Of A Parallel Two-Dimensional Jet In Supersonic Flow, Josiah Mcdermott, Connor Bell, Davide Vigano

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Stabilizing combustion in supersonic flows is a formidable challenge due to the small time scales afforded for air-fuel mixing. Numerous studies in this area have demonstrated the potential of strut-style platforms for fuel injection and mixing enhancement, which remains an active area of research. In the Aerodynamics Research Laboratory at Missouri S&T, a strut-style injector system has recently been installed. In this study, we characterize the flow structures behind this platform in a range of injection pressures and corresponding mass flux ratios. The wake generated by a strut and injection plume, even absent combustion or mixing enhancement geometry, has an …

Supersonic Wind Tunnel Free Stream Turbulence Characterization Using 2-Point Focused Laser Differential Interferometry, Joseph Villarreal, Joshua Gary, Davide Vigano

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Non-intrusive laser-based diagnostics, such as Two-Point Focused Laser Differential Interfer-ometry (2-FLDI), play a crucial role in modern aerodynamic research by enabling simultaneous measurements of density and velocity in compressible flows. A 2-FLDI system has been developed and implemented for the Missouri S&T Supersonic Wind Tunnel to characterize free stream turbulence fluctuations and free stream convective velocity. Design choices that enabled the 2-FLDI to overcome low turbulence to measure free stream velocity are detailed. The free stream velocity measurements are validated against previous particle image velocimetry data, showing good agreement. Analysis of normalized velocities and density-based turbulence intensities found that the …

2-Point Focused Laser Differential Interferometry Measurements Of A Parallel Jet In Supersonic Flow, Joshua Gary, Joseph Villarreal, Davide Vigano

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Turbulence in compressible flows plays a central role in applications such as air-fuel mixing in supersonic combustors and is significantly more complex than incompressible turbulence due to the presence of fluctuating thermodynamic quantities. As such, models like the Strong Reynolds Analogy (SRA) are used to relate these quantities. However, SRA validity has been examined primarily in boundary-layer flows. In this work, a newly developed Two-Point Focused Laser Differential Interferometry (2-FLDI) system is implemented in a two-dimensional parallel supersonic jet. The diagnostic is described in detail, including optical alignment procedures, calibration methods, and data analysis techniques. Measurements acquired at multiple streamwise …

Adaptive Machine Learning Framework For Microstructural Optimization And Mechanical Performance Prediction In Steels, Henry Adekola Haffner

Doctoral Dissertations

Evolution of microstructures, such as polygonal ferrite, acicular ferrite, bainite, and martensite, plays a pivotal role in determining the final microstructural and mechanical properties of steel products. Given the established inter-relationship between processing parameters, microstructure, properties, and performance, precise control of phase transformation is essential to achieve pre-determined properties. To understand transformation routes in different steel grades, time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams are necessary and can be described using the Johnson-Mehl-Avrami-Kolmogorov equation and Scheil’s additivity rule. This study presents a comprehensive computational framework for predicting and optimizing microstructure and mechanical properties in advanced high-strength steels (AHSS) using adaptive machine …

Passive Communication Across Diverse Swarm Formations And Scales Utilizing Wake Signatures For Messaging And Object Inference, Bryan Varela

Open Access Master's Theses

Passive wake signatures in fluid flows can support perception and low-rate communication in swarms. In cluttered or contested underwater environments, conventional acoustic, radio, and optical links can be power-hungry, intermittent, or undesirable when low observability is required. Wake-mediated cues offer a local, directional channel that does not require line of sight because each agent naturally sheds coherent vortices that persist downstream and can be sampled by followers with only a small number of probes.

This study evaluates whether sparse downstream probes are sufficient to infer agent attributes and decode simple messages from wakes generated by established source shapes. Computational fluid …

Development Of An Active Heave Compensation System On A Cost Effective Microcontroller For A Fiber Optic Tether Management System, Frances Truong

Open Access Master's Theses

Fiber optic tether systems are used for real-time data transmission to remotely operated vehicles (ROV) due to their ease of deployment and light weight, but are prone to damage from tension loads. An active heave compensation system applied to a fiber optic tether system can address these challenges by actively managing the tether payout to reduce peak loads. Tether management systems with active heave compensation have been in use for larger systems such as work class vehicles and offshore oil rigs, but few are developed for small maritime systems. This work focuses on the development and incorporation of an active …

Effect Of Kelvin Seamount On Acoustic Propagation, Lindsey Moss

Open Access Master's Theses

This thesis contains CUI. It cannot be distributed, exported, uploaded, or published until it has gone through the proper public release process.

Field-Assisted Post-Processing Of Cold-Sprayed Pure Copper, Alan Hensley

Theses and Dissertations--Mechanical and Aerospace Engineering

The properties of materials processed through cold spray, and many other AM processes, are non-uniform and unpredictable. In most cases, post-processing is required to achieve desired properties and better uniformity. In cold spray, the typical method is an annealing heat treatment (AHT), which can improve bond strength, reduce porosity, and restore ductility, among other effects. AHT alone, however, is unable to completely remedy any of the unfavorable properties. In addition, long treatments at high temperatures are often needed for satisfactory results. This increases energy consumption and extends production times for products made by the process. For these reasons, numerous investigations …

Multiphysics Transport In Porous Thermal Protection Systems: Experimental Characterization Of Gas Permeability And Radiative Properties, Yejajul Hakim

Theses and Dissertations--Mechanical and Aerospace Engineering

Porous thermal protection systems (TPS) used in hypersonic vehicles exhibit coupled gas and radiative transport across multiple regimes and length scales. Accurate performance prediction requires reliable characterization of permeability, slip-flow behavior, and radiative transport properties, particularly for low-permeability and charred materials where existing data are limited. This dissertation presents experimental methods for characterizing multiphysics transport in porous TPS materials. A modular flow system was developed to measure permeability and slip behavior in both virgin and charred materials under relevant environments. A transient pressure decay method enables accurate permeability estimation in low-permeability regimes and provides insight into effective pore structure. Results …

Reciprocity-Based Transfer Function Techniques For Acoustic Source Reconstruction, Spring Isolator Characterization And Structural Damping Assessment, David Pum Thian Lal Paite Neihguk

Theses and Dissertations--Mechanical and Aerospace Engineering

Reciprocity implies that a system responds identically when the source and receiver positions are interchanged. This dissertation applies this principle to address three practical challenges in noise and vibration characterization, where conventional approaches are limited by inaccessible interfaces, constrained excitation conditions, or metrics that do not fully capture vibroacoustic behavior.

The first study develops and validates an inverse method to characterize ducted acoustic sources using acoustic free velocity. Acoustic reciprocity is applied to simplify transfer function measurements. The method is extended to large cross-section ducts, where the source is reconstructed as a collection of point sources along a plane. Validation …

Process-Guided Learning Via Data-Driven Modeling And Controller Synthesis, Benton Clark

Theses and Dissertations--Mechanical and Aerospace Engineering

This work introduces process-guided learning, a framework in which process characteristics and learning algorithms are combined in the modeling process of engineering applications with the aim of uniting traditional and data-driven modeling and control techniques. Traditional engineering methods using simplified analytic models fail to capture the increasing complexities of engineering problems with sufficient accuracy to achieve modern requirements. More advanced modeling and control techniques using high-fidelity models often produce a computational burden that is infeasible for real-time solutions. Data-driven modeling offers a simple and flexible algorithm for producing real-time capable, high-fidelity models, but naive implementations lack the physical constraints of …

A Full Polymer Piezoelectric Flextensional Energy Harvester, Nadia Ahbab, Sidra Naz, Bingqi Zhao, Tian-Bing Xu

Mechanical & Aerospace Engineering Faculty Publications

This study presents a full polymer piezoelectric flextensional energy harvester (FPPFEH) comprising a single-layer poly(vinylidene fluoride) (PVDF) film bonded to a 3D-printed polylactic acid (PLA) flextensional frame. For an arm inclination angle of θ=10°, the free-body model gives a theoretical geometric force-amplification factor of M_F=cot θ ≈ 5.67; this value represents an ideal upper bound and was not independently validated by local force or strain measurements. During assembly, the film was tensioned only to remove visible slack and maintain a flat configuration. No intentional pretension was applied, and any residual tension was not measured. Off-resonance force-controlled tests showed …

Computational Modeling And Machine Learning For The Design Of Polymer-Based Protective Systems Under Dynamic Loading, Jonathan Tate Villada

Open Access Dissertations

Computational modeling and machine learning offer powerful pathways for designing polymer-based protective systems subjected to dynamic loading, particularly for mitigating the early shock-dominated response generated by near-field underwater explosions (UNDEX). As naval, offshore, and submerged infrastructure systems continue to grow in strategic importance, there is an increasing need for lightweight, damage-tolerant protective solutions capable of reducing transmitted pressure, deformation, and energy transfer under extreme impulsive environments. Since large-scale experimental testing under such conditions are costly and limited, validated numerical frameworks provide an efficient means to evaluate polymeric coatings, architected metastructures, and data-driven predictive tools across broad design spaces. The first …

Extending Low-Frequency Traveling-Wave Propagation In A Water-Filled Cylindrical Waveguide Using Active Impedance Control, William Slater

Open Access Dissertations

This dissertation investigates extending the frequency range over which a one-dimensional, plane traveling wave can be generated in a water-filled, steel-walled waveguide under ocean temperature and hydrostatic pressure conditions. The wave guide considered is a thick-walled, steel cylinder filled with a water/glycol mixture with a transducer at each end and a hydrophone array along the length. One transducer excites a plane wave while the other cancels reflections, resulting in a traveling wave in the waveguide. The current (open-loop) measurement system is advertised to generate traveling waves for low frequencies where only 3.4% of a wavelength can be measured (kL …