Mechanical Engineering Commons^™

Comparative Evaluation Of Investigation Methods For Estimating The Load-Dependent State Of Charge And End Of Discharge Of A Multirotor Uav Battery, Hanna Dibbern, Morten Roßberg, Claudia Werner

Journal of Aviation Technology and Engineering

As the scope of multirotor unmanned aerial vehicle (UAV) applications increases, more attention is being paid to UAV energy requirements, which vary depending on the mission profile. To obtain accurate information about the UAV battery during flight, the idea of a digital twin including a battery state estimation model is promising. For battery state estimation, a Kalman filter combination is the preferred approach in the literature. Comparing different Kalman filters, the unscented Kalman filter has a more accurate estimation for nonlinear systems compared to the extended Kalman filter. In the application of UAV flight with load-dependent flight missions, the comparison …

Stereoscopic-Based Mass Properties Estimation For Warhead Fragments, Alessia Nocerino, Katharine Larsen, Riccardo Bevilacqua, Elisabetta L. Jerome

Student Works

FRAGMENTATION characteristics such as spatial distribution, number of fragments, fragment velocity, and fragment mass can be used to characterize the lethality of a fragmenting weapon or any metal cased explosive [1,2]. However, most warhead tests and evaluations are limited to static arena testing, where fragment characteristics must be collected by hand. Recently, stereoscopic imaging techniques have been added to static arena tests. Using this method, position tracks can be collected for each fragment, and then velocity information can be found. This paper proposes a method to estimate the mass and moment of inertia using data collected by a stereoscopic imaging …

Employment Of Intelligent Predictive Maintenance On Thermal Power Plant Component Parts Taking Condenser Vacuum As A Case Study, Titus Ajewole

Tanzania Journal of Engineering and Technology (TJET)

This work proposes deployment of machine learning in the maintenance of individual constituent parts of steam power plant assemblages. With the condenser vacuum of a steam turbine (in a six-turbine plant assemblage) taken as a case study, information on the past operating parameters of the selected plant component was used to forecast its future working condition. Based on Exponential Gaussian Process of Regression, a model was developed, trained using the diachronic operational data, and employed in determining the future. A quantitative evaluation was employed to provide the distribution of the test values of the data about the lines of regression, …

Wind Farm Optimization And Analysis Of Complex Wake Structures, Rubel Chandra Das

Mechanical Engineering ETDs

A high-fidelity computational solver was developed with direct numerical simulation (DNS), large eddy simulation (LES), and Concurrent Precursor Method (CPM) capabilities. Extensive validation ensured the solver's accuracy in modeling fluid dynamics, including the wake characteristics of both utility and miniature-scale wind turbines. Key performance statistics (e.g., velocity and turbulence intensity profiles) were compared against established theoretical, computational, and experimental results. The study examined the influence of ground clearance on turbine performance, comparing two scenarios with different hub heights. Results showed that larger ground clearance facilitates quicker wake recovery. Finally, the study uses a nine-turbine array model to explore wind farm …

Computational Modeling Using A Novel Continuum Approach Coupled With Pathway-Informed Neural Networks To Optimize Dynein-Mediated Centrosome Positioning In Polarized Cells, Arkaprovo Ghosal, Padmanabhan Seshaiyar Dr., Adriana Dawes Dr., General Genomics Inc.

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Wire Electrical Discharge Machining Of Aisi304 And Aisi316 Alloys: A Comparative Assessment Of Machining Responses, Empirical Modeling And Multi-Objective Optimization, Mona Aboueleaz, Noha Naeim, Islam Abdelgaliel, Mohamed Aly, Ahmed Elkaseer

Mechanical Engineering

This research investigates the multi-response of both material removal rate (MRR) and surface roughness (Ra) for the wire electrical discharge machining (WEDM) of two stainless steel alloys: AISI 304 and AISI 316. Experimental results are utilized to compare the machining responses obtained for AISI 316 with those obtained for AISI 304, as previously reported in the literature. The experimental work is conducted through a full factorial experimental design of five running parameters with different levels: applied voltage, transverse feed, pulse-on/pulse-off times and current intensity. The machined workpieces are analyzed using an image processing technique in order to evaluate the size …

Development, Implementation, And Evaluation Of Swirl-Combustion Strategies For Optimal Performance Of Ammonia As A Fuel For Gas Turbine Engines, Varun Nanjunda Rao Viswamithra

LSU Doctoral Dissertations

In an effort to reduce harmful effects of greenhouse gas emissions, ammonia is being pursued as a fuel for power generation as it is a carbon-free energy source. However, the use of ammonia-air mixtures in premixed swirl combustors poses challenges due to low flame speed and reactivity resulting in combustor stability issues in addition to high Nitrous Oxide (NOx) emissions due to the presence of fuel-bound Nitrogen. The first part of this study attempts to overcome lean blowout limits of methane-ammonia-air mixtures using a novel, multi-point () injection strategy, whereby micron-sized holes on the swirler vanes generate a co-flowing stream …

Thermo-Mechanical Instabilities In Next-Generation Friction Materials In High-Speed Sliding Systems, Kingsford Koranteng

Electronic Theses and Dissertations

For centuries, the manufacturing industry has incorporated metals like copper into friction materials to enhance thermal properties and minimize thermo-mechanical instabilities (TMI) in high-speed sliding systems. Unfortunately, these metals have adverse environmental effects due to the emission of hazardous particulate matter. As a result, there is a growing movement towards adopting next-generation friction materials as an alternative solution.

The study begins by conducting experimental and numerical investigations to examine the instabilities found in metal-based friction materials. The primary objective is to utilize the insights gained from the investigations to computationally explore effective strategies for mitigating various instabilities that may arise …

Molecular Dynamics Study Of Characterization In Metal-Free Friction Materials, Yizhan Zhang

Electronic Theses and Dissertations

Metallic friction materials currently used in industry may adversely impact the environment. Substitutions for metals in friction materials, on the other hand, can introduce operational safety issues and other unforeseeable issues such as thermal-mechanical instabilities and insufficient strength. In view of it, this dissertation focuses on developing different kinds of materials from simple structure to complex structure and evaluating the material properties with the assistance of molecular dynamics (MD) tools at the nano scale.

First, the concept of the contacted surfaces in friction at the atomic scale was introduced in order to get accurate understanding of the friction process compared …

Changes In Balance With Brain Inflammation: Sensitivity In Dual Motor Mechanisms, Hannah Mcdade

Electronic Theses and Dissertations

Concussion assessment in athletes has gained prominence due to potential long-term consequences of traumatic brain injuries. Evaluating balance alterations is crucial for understanding post-injury motor control strategies. This study introduces a novel approach to understanding center of pressure (COP) dynamics during quiet stance tasks for assessing balance impairments in athletes recovering from concussion. Concussed athletes often experience impaired motor function and cognitive deficits, increasing the risk of orthopedic injury. Traditional balance assessments focus on total COP (COPt), overlooking nuanced hip and ankle mechanisms. This research investigates COP variations between constant loading (COPc) and variable loading (COPv) signals in concussed athletes …

Pedicle Screw Placement Accuracy In Robot-Assisted Spinal Fusion In A Multicenter Study, Victoria L. Volk, Keegan A. Steele, Mia Cinello‑Smith, Richard V. Chua, John Pollina, Gregory Poulter, Eiman Shafa, Peter Busselberg, Clare K. Fitzpatrick

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Pedicle screw fixation is a spinal fusion technique that involves the implantation of screws into vertebral pedicles to restrict movement between those vertebrae. The objective of this research is to measure pedicle screw placement accuracy using a novel automated measurement system that directly compares the implanted screw location to the planned target in all three anatomical views. Preoperative CT scans were used to plan the screw trajectories in 122 patients across four surgical centers. Postoperative scans were fused to the preoperative plan to quantify placement accuracy using an automated measurement algorithm. The mean medial–lateral and superior–inferior deviations in the pedicle …

Analysis Of Bombyx Mori Silk And Polyimide Nanofibers, Sabrina Leseul

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents a study on the properties of Bombyx Mori silk nanofibers and polyimide (PI) nanofibers. Firstly, a Bombyx Mori silk solution has been created with degummed silkworm cocoons in order to separate the fibroin and the sericin, the two main proteins of the silk. The fibroin was then centrifuged to remove insoluble particles and stored and 4°C before mixing with hexafluoroisopropanol (HFIP). On the second part, a polyimide solution, made with shavings of polyimide and N,N-dimethylformamide (DMF). Both solutions are then electrospun. Electrospinning parameters are studied. In this way, a part of my thesis has been dedicated to …

Applications Of Femtosecond Laser-Processed And Nanoneedle-Synthesized Surfaces To Enhance Pool Boiling Heat Transfer, Peter Efosa Ohenhen

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In the present work, the integration of femtosecond laser surface processing (FLSP) with copper hydroxide on hybrid surfaces was examined. The goal was to determine the impact on pool boiling enhancement. The samples for the investigation were fabricated by first functionalizing with FLSP, and the process was then followed by citric acid cleaning (CAC) to eliminate the oxides generated on the copper surface during the FLSP process. After the citric acid cleaning, the samples were immersed in ethanol and subjected to an ultrasonic bath for 25 minutes. This step was performed to eliminate any residual citric acid and loose particles. …

Design And Scale Model Of Wave Generator For The Testing Of Wave Energy Conversion Devices, Amanda Olla

Master's Theses

As the climate crisis draws more concern, research and development in wave energy as a renewable energy source has increased. Devices such as wave energy converters (WECs) are being researched, tested, and implemented to make wave energy a competitive power source. Testing of these devices is limited due to environmental concerns such as weather, location, and other issues. WECs require testing in a marine environment, however, performing testing in the actual environment may be difficult due to weather, access, mounting, and other issues. To eliminate environmental unknowns from testing, a wave simulator device can mimic wave behavior without the need …

Amplitude-Voltage Response Of Parametric Resonance Of Electrostatically Actuated Circular Membranes, Marcos Alipi, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with the amplitude-voltage response of parametric resonance of electrostatically actuated MEMS circular membranes resonator for sensing applications. The system consists of a flexible circular membrane over a parallel ground plate. A soft AC voltage is applied between the MEMS membrane and ground plate to actuate the membrane near its first natural frequency. Two methods of investigation are used in this research, namely the method of multiple scales (MMS), and the reduced order model (ROM). These methods were used to solve for the voltage response of the MEMS analytically and numerically. This work also reports the effects the …

Searching For Unknown Material Properties For Am Simulations, Aaron Flood, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing (AM) simulations are effective for materials that are well characterized and published; however, for newer or proprietary materials, they cannot provide accurate results due to the lack of knowledge of the material properties. This work demonstrates the process of the application of mathematical search algorithms to develop an optimized material dataset which results in accurate simulations for the laser directed energy deposition (DED) process. This was performed by first using a well-characterized material, Ti-64, to show the error in the predicted melt pool was accurate, and the error was found to be less than two resolution steps. Then, …

Implementation Of Experimental Static Recrystallization Of High Strength Steel Into Computational Simulation Of Multi-Pass Slab Hot Rolling, S. K. Dasari, S. Ganguly, A. Abutunis, K. Chandrashekhara, M. F. Buchely, S. N. Lekakh, R. J. O'Malley, T. Natarajan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microstructural changes and softening due to static recrystallization have a critical influence on thermo-mechanical behavior of high strength steels during industrial multi-pass hot rolling. Numerical simulation using finite element analysis (FEA) can be used to accurately predict the softening behavior during the hot rolling process. Therefore, the implementation of an experimentally defined static recrystallization model into FEA is necessary to get realistic simulation prediction. in this study, the extent of softening during static recrystallization in Si and Mn alloyed high strength steel was measured using double hit tests. a Gleeble™ thermo-mechanical simulator was used to perform the double hit tests …

Comparison Of The Thermal Stability In Equal-Channel-Angular-Pressed And High-Pressure-Torsion-Processed Fe–21cr–5al Alloy, Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nanostructured steels are expected to have enhanced irradiation tolerance and improved strength. However, they suffer from poor microstructural stability at elevated temperatures. in this study, Fe–21Cr–5Al–0.026C (wt.%) Kanthal D (KD) alloy belonging to a class of (FeCrAl) alloys considered for accident-tolerant fuel cladding in light-water reactors is nanostructured using two severe plastic deformation techniques of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT), and their thermal stability between 500–700 °C is studied and compared. ECAP KD is found to be thermally stable up to 500 °C, whereas HPT KD is unstable at 500 °C. Microstructural characterization reveals that ECAP KD …

Mems Cantilever Biosensors Driven By Fringe Effect: Voltage-Amplitude Response Of Parametric Resonance, Miguel A. Martinez, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with voltage-amplitude response of fringing field/effect actuated micro-electromechanical system (MEMS) cantilever beam resonator biosensors at parametric resonance. The system consists of a flexible electrode (cantilever beam) and a fixed electrode (ground plate) in parallel, connected through an AC voltage source. The electrostatic force induced is due to the parallel-plate capacitance, which is directly related to the overlapping area of the two electrodes (Palmer’s Formula). In addition, fringing field electrostatic actuation must be accounted for. This is due to the bending of electric field lines from the ground plate to the top and side walls of the cantilever …

Design Of Impact-Free Gaits For Planar Bipeds And Their Stabilization Using Impulsive Control, Aakash Khandelwal, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of designing and stabilizing impact-free gaits is considered for point-foot planar bipeds. A set of geometric constraints, which eliminate impact forces at the time of leg interchange, are used to design the gaits. A family of gaits, where the stride length and walking speed can be chosen independently for each gait, is guaranteed to exist. A continuous controller is used to enforce the constraints associated with a desired gait and intermittent impulsive inputs are applied to stabilize the gait. A five-link biped example is used to illustrate the procedure for designing impact-free gaits. The effectiveness of the continuous …

Towards A Virtual Test Framework To Predict Residual Compressive Strength After Lightning Strikes, Scott L.J. Millen, Xiaodong Xu, Juhyeong Lee, Suparno Mukhopadhyay, Michael R. Wisnom, Adrian Murphy

Mechanical and Aerospace Engineering Faculty Publications

A novel integrated modelling framework is proposed as a set of coupled virtual tests to predict the residual compressive strength of carbon/epoxy composites after a lightning strike. Sequentially-coupled thermal-electric and thermo-mechanical models were combined with Compression After Lightning Strike (CAL) analyses, considering both thermal and mechanical lightning strike damage. The predicted lightning damage was validated using experimental images and X-ray Computed Tomography. Delamination and ply degradation information were mapped to a compression model, with a maximum stress criterion, using python scripts. Experimental data, in which artificial lightning strike and compression testing were performed, was used to assess the predictive capabilities …

On Quantifying Uncertainty In Lightning Strike Damage Of Composite Laminates: A Hybrid Stochastic Framework Of Coupled Transient Thermal-Electrical Simulations, R. S. Chahar, J. Lee, T. Mukhopadhyay

Mechanical and Aerospace Engineering Faculty Publications

Lightning strike damage can severely affect the thermo-mechanical performance of composite laminates. It is essential to quantify the effect of lightning strikes considering the inevitable influence of material and geometric uncertainties for ensuring the operational safety of aircraft. This paper presents an efficient support vector machine (SVM)-based surrogate approach coupled with computationally intensive transient thermal-electrical finite element simulations to quantify the uncertainty in lightning strike damage. The uncertainty in epoxy matrix thermal damage and electrical responses of unprotected carbon/epoxy composite laminates is probabilistically quantified considering the stochasticity in temperature-dependent multi-physical material properties and ply orientations. Further, the SVM models are …

Data And Cad Models Of Cyclic Testing Of Membrane Hinges For Use In Origami-Inspired Design, Mitchel Skinner

ScholarsArchive Data

The following includes results and CAD models of cyclic testing of membrane hinges for use in origami-inspired design. The results include the number of cycles until both visual damage and complete failure occurred in 7 different membrane materials. The CAD models of the testing setup are also included.

Ai-Based Bridge And Road Inspection Framework Using Drones, Hovannes Kulhandjian

Mineta Transportation Institute

There are over 590,000 bridges dispersed across the roadway network that stretches across the United States alone. Each bridge with a length of 20 feet or greater must be inspected at least once every 24 months, according to the Federal Highway Act (FHWA) of 1968. This research developed an artificial intelligence (AI)-based framework for bridge and road inspection using drones with multiple sensors collecting capabilities. It is not sufficient to conduct inspections of bridges and roads using cameras alone, so the research team utilized an infrared (IR) camera along with a high-resolution optical camera. In many instances, the IR camera …

A Generalized Machine Learning-Based Classifier Considering Cost-Effective Features For Automated Fault Detection And Diagnosis (Afdd) Of Packaged Rooftop Units, Md Rasel Uddin

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Packaged rooftop units (RTUs) are widely used for space conditioning in commercial buildings and manufacturing facilities. The typical soft faults related to RTUs degrade the system's performance in terms of cooling capacity, power consumption, and Coefficient of Performance (COP), detrimentally affecting both the equipment and energy consumption and the environment. Previous research in soft fault detection for rooftop units lacked classifier validation using lab and field data, developing a generalizable algorithm, and analyzing its performance across varying fault intensities.

Using a simulated data library for multiple rooftop units, this study proposes a machine-learning classifier with a reduced set of 9 …

Digital Twins Of The Living Knee: From Measurements To Model, Thor Erik Andreassen

Electronic Theses and Dissertations

Modern medicine has dramatically improved the lives of many. In orthopaedics, robotic surgery has given clinicians superior accuracy when performing interventions over conventional methods. Nevertheless, while these and many other methods are available to ensure treatments are performed successfully, far fewer methods exist to predict the proper treatment option for a given person. Clinicians are forced to categorize individuals, choosing the best treatment on “average.” However, many individuals differ significantly from the “average” person, for which many of these treatments are designed. Going forward, a method of testing, evaluating, and predicting different treatment options' short- and long-term effects on an …

Kinematic Analysis Of Gait And Deep Knee Flexion For Pre- And Post-Operative Total Knee Arthroplasty, Samantha Collins

Electronic Theses and Dissertations

Osteoarthritis (OA) is a form of arthritis that develops in the joint due to overuse and aging causing pain, discomfort, and disability. Total Knee Arthroplasty (TKA) is a surgical procedure performed when OA symptoms are severe with an estimated 600,000 patients in the United States currently receiving TKA. Studies have reported dissatisfaction of the knee for 14-39% of patients. This study collected knee kinematics before and after surgery using stereo radiography for precise measurement of gait and deep knee flexion activities. Results showed healthy knee kinematics were not restored and no significant changes could be seen from OA kinematics in …

Experimental Study Of Central And Side Jet With And Without Chevron Nozzle Exit On Gas Turbine Leading Edge Jet Impingement Cooling, Ahmad Yousef Alqasrawi

Theses

This thesis presents a comprehensive investigation into the application of jet impingement cooling on turbines blade leading edge. Gas turbines are extensively utilized in power generation and aerospace industries, where efficient cooling techniques are crucial to enhance the performance and lifespan of turbine blades. The leading edge of a turbine blade is particularly vulnerable to high-temperature exposure and thermal stresses, making it an essential area for effective cooling strategies. Jet impingement cooling is one of the most effective cooling techniques mostly used in the leading edge of rotating and stationary blades. This study aims to explore the performance of jet …

Multicolor Dye-Based Flow Structure Visualization For Seal-Whisker Geometry Characterized By Computer Vision, Ondřej Ferčák, Kathleen Lyons, Christin T. Murphy, Kristina M. Kamensky, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Pinniped vibrissae possess a unique and complex three-dimensional topography, which has beneficial fluid flow characteristics such as substantial reductions in drag, lift, and vortex induced vibration. To understand and leverage these effects, the downstream vortex dynamics must be studied. Dye visualization is a traditional qualitative method of capturing these downstream effects, specifically in comparative biological investigations where complex equipment can be prohibitive. High-fidelity numerical simulations or experimental particle image velocimetry (PIV) are commonplace for quantitative high-resolution flow measurements, but are computationally expensive, require costly equipment, and can have limited measurement windows. This study establishes a method for extracting quantitative data …

An Investigation Into The Challenges Of Contemporary Additive Manufacturing: Insights Into The Metallurgical Response Of Materials And Relevant Solution, Huan Ding

LSU Doctoral Dissertations

Additive Manufacturing (AM) has gained attention in recent years due to its unique capabilities in the fabrication of complex parts. As with any new research, there is still a lack of sufficient understanding in the field of additive manufacturing, and further investigation is needed to solve existing problems. Ultimately, the aim is to enable the widespread use of AM components across various industries.

Chapter One provides a brief introduction to the background and current bottlenecks of additive manufacturing technology. Chapter two focuses on the development of high-strength 7075 aluminum alloy (Al7075) for Fused Deposition Modeling and Sintering (FDMS) technology. Al7075 …