Mechanical Engineering Commons^™

High-Throughput Characterization Of Creep In Additively Manufactured 316l Stainless Steel, Raushan Kumar Singh

All Graduate Theses and Dissertations, Fall 2023 to Present

Advanced materials are widely used in industries such as nuclear energy, aerospace, and automotive engineering, where components are exposed to extreme temperatures and stresses over long periods of time. As new materials continue to emerge, researchers need efficient ways to evaluate their mechanical performance so they can be used safely and effectively. Among several mechanical challenges, creep is a major concern in these conditions. Creep is a type of mechanical failure in which materials gradually deform when exposed to high temperatures and constant load. Conventional methods for evaluating creep typically involve testing a single specimen at a time, which can …

Prompt-Driven Tabletop Robotic Manipulation With A Structured Llm Interface And Visual Verification, Tomas Franco

Master's Theses

Creating a tabletop robotic manipulation system that connects language goals to robot actions is a challenging problem. Large language models can interpret mission objectives and reason through actions, but when placed directly in control of hardware they can produce hallucinated commands that result in unsafe behavior without the proper safeguards.

This thesis presents a constrained LLM-guided manipulation system built around the Quanser Qarm, a four degree of freedom manipulator with a mounted Realsense RGB-D camera and a gripper with readable current. Every decision made by the LLM planner is routed through a gated command interface that restricts the model to …

Development And Testing Of A Computer Vision Pose Estimation System For Planar Mobile Robots, Andrew Jones

Master's Theses

This thesis details the development and testing of a computer vision-based real-time pose estimation system for differential drive robots. A single camera with a fisheye lens is used to locate ArUco markers placed at fixed locations and attached to robots. Using the OpenCV library, the Perspective-n-Point (PnP) problem is solved to facilitate the transformation of 2-D robot positions in an image to world-frame coordinates. An analytical solution is presented to estimate robot poses based on a single PnP solution, rather than solving the PnP problem for each pose estimate. Pose information is relayed to individual robots using a multi-microcontroller architecture …

Automated Guided Wave Characterization Of Marcelling: In-Plane Fiber Waviness In Thermoplastic Composites, Sourav Banerjee, Ana Tudor, Corey Leydig, Thomas Ferguson, Tally Bovender, Darun Barazanchy, Josh Widosky, Paul Ziehl

Faculty Publications

Thermoplastic composite (TPC) materials often develop in-plane fiber waviness during manufacturing, a defect known as marcelling. Marcelling negatively impacts the strength and overall performance of the composite and are hard to control. While it may appear as a surface imperfection, it can also extend partially through the thickness of the material. Currently, there is no established nondestructive evaluation (NDE) method to reliably detect and quantify marcelling in composites after manufacturing. As marcelling is not a local defect but spans across the surface in in-plane dimensions of the structure, traditional pulse-echo and phased-array ultrasonic NDE are ineffective. Automated multi-directional guided …

Thermal Conversion Of Cotton Gin Byproducts Into Liquid Fuels And High-Value Chemicals, Emmanuel Asare

Mechanical Engineering Theses

In this study, we performed fast pyrolysis, catalytic fast pyrolysis (CFP), and catalytic hydropyrolysis (CHP) of cotton gin byproducts (CGB) to investigate their conversion into hydrocarbon-rich liquid fuels and high-value aromatic chemicals. Five CGB fractions (CC1, CC2, SM, TM, and FCGB) were collected from different stages of cotton ginning operation and characterized by proximate, ultimate, and higher heating value (HHV) analysis. The feedstocks contained 41.5 44.8 wt.% carbon, 54.2–58.5 wt.% volatile matter, 6.0–15 wt.% ash, and higher heating values of 15.2–16.8 MJ kg⁻¹. All pyrolysis experiments were performed using a Pyroprobe 5200 coupled with GC-MS/FID, while catalyst loading, hydrogen pressure, …

Theory, Implementation, And Practical Applications Of A Modern Parabolized Navier-Stokes Code, Logan B. Freeman

All Graduate Theses and Dissertations, Fall 2023 to Present

The Parabolized Navier-Stokes (PNS) method is a specialized computational approach for solving the equations that govern fluid flowing faster than the speed of sound, known as supersonic flow. By leveraging unique physical properties of supersonic environments—specifically that information cannot travel upstream—this method allows for significantly more efficient calculations than traditional approaches. Supersonic flows are important for many military and civilian applications including hypersonic weapons, high-speed passenger aircraft, and reentry. This thesis provides a comprehensive review of the two-dimensional PNS formulation, detailing the mathematical derivation and its practical implementation for solving flow problems. Through performance analysis and error assessment, this research …

A Cfd-Dem Framework For Characterizing Nanoparticle Adhesion Effects On Creeping-Flow Permeability In Composite Manufacturing, Gavin Stoker

All Graduate Theses and Dissertations, Fall 2023 to Present

Modern aircraft, spacecraft, and high-performance vehicles are increasingly built from composite materials, engineered combinations of plastics and fibers that are lighter and stronger than traditional metals. Researchers are now pushing these materials further by mixing in microscopic particles thousands of times smaller than a human hair, called nanoparticles, to make them even tougher and more resistant to damage. The challenge is getting those nanoparticles distributed evenly. During manufacturing, liquid plastic resin is pumped through a network of tightly packed fibers, carrying the nanoparticles along with it. But nanoparticles tend to clump together and stick to surfaces as they travel, clogging …

0905: American Car And Foundry (Acf) Collection, 1916-2019, Marshall University Special Collections

Guides to Manuscript Collections

The collection includes only documents that were found in the plant in 2021. These primarily consist of files on capital projects from the 1970s through the 1990s. Also included are notebooks with job descriptions and classifications; ledger books containing maintenance purchase orders; quality assurance manuals; visitors register books from 1973-2019; drawings of plant machinery and operations; slides and photographs; and miscellaneous materials.

The forerunner to ACF was Ensign Manufacturing Company, founded in 1871 at Huntington, West Virginia, by William H. Barnum and Ely Ensign, both from prominent families of Lime Rock, Connecticut. It was chartered (incorporated) on November 1, 1872, …

Smart Process Planning For Automated Fiber Placement, Matthew J. Godbold

All Dissertations

Automated Fiber Placement (AFP) is a preeminent manufacturing technology for producing high-performance composite structures, offering precise material placement, reduced waste, and the potential for highly optimized lightweight designs. While AFP has been widely adopted in aerospace applications, its broader use across industries such as automotive, wind energy, maritime, and sporting goods remains limited. A key barrier to wider adoption is the traditional separation of design, manufacturing, and inspection processes, which drives up cost and results in inefficiencies, sub-optimal designs, and limited feedback between lifecycle stages. In current practice, manufacturing is treated as an isolated process, disconnected from early-stage design decisions …

Integrated Power, Energy, And Thermal Management For Autonomous Hybrid Off-Road Vehicles: Multi-Timescale Modeling, Predictive Control, And Resilient Thermal Design, Anirudh Sundar

All Dissertations

Electrification and autonomy are increasingly important for off-road vehicles operating in construction, agriculture, mining, defense, and other demanding environments. These platforms must deliver high tractive power under unstructured terrain, harsh ambient conditions, low-speed operation, and large auxiliary loads. While hybrid and electrified powertrains offer improved efficiency, mobility, and auxiliary power capability, they also introduce significant challenges in managing tightly coupled power, energy, and thermal subsystems. In particular, lithium-ion batteries, power electronics, electric machines, and internal combustion engine-generator systems operate across different temperature limits and timescales, requiring coordinated management to ensure efficiency, durability, and safe operation. This dissertation develops modeling, planning, …

Microstructural Shielding And Advanced Fatigue Crack Analysis In The Presence Of Deformation Twinning, Seyed Ali Asli

All Dissertations

Design methods to mitigate fatigue failures have remained relatively stagnant, as engineers have relied on existing continuum-level models and adhered to the damage tolerance design methodology. Although damage-tolerant design has led to increased safety, extended component in-service life, and better life predictions, it still relies on maintenance routines to identify dangerous cracks. This research aims to test the hypothesis that bundles of deformation twin boundaries will increase the resistance to fatigue crack growth (FCG). Slip and twinning are two dominant mechanisms of plastic deformation in metals. Slip is more common in materials with face-centered cubic (FCC) crystal structures at room …

Investigating The Impacts Of Information Framing And Representation On Multi-Stakeholder Decision-Making For Tradespace Exploration, Meredith G. Sutton

All Dissertations

Tradespace exploration (TSE) is a decision-making process used in engineering design to search through a tradespace, containing all potential solutions to a design problem and their performance evaluations, in order to select optimal or near-optimal solutions. Solution optimality is driven by a desire to maximize the overall utility of a solution, which often cannot be done without making tradeoffs or compromises. The TSE process requires vast amounts of information which can be difficult to generate and understand, often leading to challenges including information overload, delays in decision-making, and suboptimal decisions, even for the most experienced designers. To address the challenges …

A Verification And Validation Framework For Model-Based Systems Engineering Using Executable Architecture Models And Integrated Simulation, Michael O. Cruz

Open Access Theses & Dissertations

Model-Based Systems Engineering (MBSE) reaches its full value when architecture does more than describe a system. It should help engineers carry stakeholder need and system intent into executable analysis, preserve the configuration and criteria used, and return evidence that can be reviewed in the same architecture context. This dissertation develops and evaluates a seven phase, architecture-driven verification and validation framework for that purpose. The framework defines the responsibilities that connect SysML architecture, controlled execution, domain simulation, configuration management, persistent data, analytics, and accountable engineering review. A reusable Cameo/SysML digital test environment plugin provides the reference implementation for orchestration and model …

A Hybrid Machine Learning-Based Feasibility Prediction Of 3d Mechanical Designs Using Scalar And Geometric Features, Md Mohsin Uddin Fahim

Open Access Theses & Dissertations

The computational bottleneck of structural feasibility screening frequently hinders the transition from a digital 3D model to a physically manufactured component. Traditionally, engineers have relied on either overly rigid heuristic constraint checks or computationally exhaustive finite element simulations. To address this inefficiency, this thesis proposes and validates a hybrid machine-learning framework to predict the structural manufacturability of 3D mechanical designs. Moving beyond the conventional reliance on isolated scalar parameters, the proposed methodology extracts and integrates both scalar manufacturing constraints (e.g., tolerance, minimum feature thickness) and spatial geometric descriptors (e.g., bounding volume, aspect ratio) directly from STL mesh data. Utilizing a …

Machine Learning For Predictive Energy And Emissions Modeling Of Vehicles And Power Grids In The United States, S M Tanvir Faysal Alam Chowdhoury

Dissertations

The environmental benefits of electric vehicle (EV) adoption depend on more than replacing internal combustion engine vehicles with electric powertrains. EV adoption reshapes electricity demand, interacts with regional generation mixes, and influences travel behavior and congestion, creating a coupled transportation-energy system in which vehicle and power-plant emissions must be evaluated together. This dissertation develops machine-learning frameworks for predicting energy consumption and emissions from vehicles and power grids under rising EV adoption. The first component forecasts grid emissions from EV charging. Using simulation data from NREL's Cambium database, a Prophet-based time-series framework predicts carbon dioxide, nitrous oxide, and methane emission rates …

Spatial Structure And Energy Content Of Wakes Behind Single And Arrayed Undulated Cylinders, Taiga Naomi Drucker-Boisvert, OndˇRej FerˇCák, Jérémie Auzoux, Sarah E. Smith, Zein Sadek, Rowan Moore, Christain T. Murphy, Trevor Dunt, Jennifer A. Franck, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Biologically inspired undulated cylinder geometries significantly influence wake structure and vortex-induced vibrations in turbulent flows, yet the underlying mechanisms are not fully understood. It is further unknown how these influences extend to multi-cylinder arrays, where interacting wakes accumulate and mix. This study examines the wake characteristics of an undulated cylinder and a smooth elliptic cylinder in single- and multi-cylinder array configurations, using particle image velocimetry and proper orthogonal decomposition (POD). Relative to the smooth elliptic cylinder, the undulated geometry induces pronounced spanwise-axial variability, characterized by enhanced near-wake mean momentum and weak far-wake signatures, consistent with reduced turbulent kinetic energy. While …

Time-Frequency Analysis Of Arterial Pulse Signals Of Cardiovascular Disease Patients Measured By A Microfluidic-Based Tactile Sensor, Md Mahfuzur Rahman

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a single-degree-of-freedom (SDOF) based time–frequency analysis framework that can simultaneously extract a comprehensive set of cardiovascular autonomic indices from arterial pulse wave recordings obtained at rest and post-exercise, supporting non-invasive monitoring of autonomic recovery during cardiac rehabilitation. The framework rests on three technical contributions.

First, an SDOF analytical model of motion artefacts quantifies two physically distinct distortion mechanisms: additive baseline drift and Time-Varying System Parameter (TVSP) generated distortion of the Tissue-Contact-Sensor (TCS) stack. Baseline drift is slowly varying and removable by filtering; TVSP distortion rides on all harmonics of the true pulse signal and cannot be removed …

A Transfer-Learning And Continuous Optimization-Based Framework For Predicting Heat Treatment-Dependent Mechanical Properties Of Ded-Processed Low-Alloy Steels, Atiqur Rahman, Sung Heng Wu, Ranjit Joy, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Directed energy deposition (DED) of low-alloy steels involves strongly coupled effects among alloy composition, solidification behavior, and post-deposition heat treatment, making mechanical property prediction difficult when target-domain data are limited. This study develops a transfer-learning and continuous optimization framework for predicting heat treatment-dependent yield strength (YS), ultimate tensile strength (UTS), hardness (HV), and as-solidified phase fractions of martensite, ferrite, and austenite in DED-processed low-alloy steels. A CALPHAD-based dataset was generated for 125 low-alloy steel compositions. A multilayer perceptron (MLP) surrogate was first trained as a baseline model, then fine-tuned through transfer learning and progressively updated as staged continuous optimization; the …

Review: Mechanics Of Mycelium Materials, Md Anwar Sadat Anik, Ehsanul Azim, Gerardo I. Zapata, Mohammad R. Islam

Mechanical Engineering Faculty Publications

The biological growth of fungal root structure, called mycelium, can be engineered to develop innovative fibrous and biocomposite materials. Mycelium materials have potential as sustainable alternatives to petroleum-derived materials for load-bearing applications. To realize this potential, there is an increasing effort dedicated to understanding the mechanics of mycelium materials. This work presents a systematic review of our current understanding of the mechanics of mycelium materials with a specific focus on structure–property relationships. The review first explores how the mycelium’s fiber network structure varies depending on whether it is grown as a two-dimensional (2D) membrane, a cellular foam, or as a …

Investigating Simulated Natural Gas Combined Cycle Plants (Ngcc) Performance To Address The Intermittency Of Renewables, Patrick Washington

LSU New Orleans Theses and Dissertations

The inherent intermittency of wind and solar energy challenges grid stability, requiring flexible support from natural gas combined cycle (NGCC) power plants. The objective of this study is to develop a method for evaluating the turn-down performance of the NGCC system and to identify effective strategies to operate multi-island NGCC plants to respond to intermittent power demand fluctuations driven by renewable energy integration. The simulation tool was validated against benchmark U.S. Department of Energy (DOE) subcritical Rankine cycle and NGCC cases. The methodology was then applied to evaluate part load operation, inlet fogging, hydrogen blending, and multi-island dispatch for a …