Mechanical Engineering Commons^™

Automatic Polyhedral Mesh Generation For Ship Resistance Based On The Locally Refined Cartesian Cut-Cell Method, Kwang-Leol Jeong, Dae-Won Seo

Journal of Marine Science and Technology–Taiwan

This paper introduces an automatic grid generation algorithm, based on a locally refined cut-cell method, to calculate ship resistance. Sharp edges and apexes are not accurately expressed in the cut-cell method, and the accuracy of the calculation in the turbulence boundary layer is lower than that of other body-fitted methods. In this study, an automatic mesh generation method is developed to effectively represent edge and apex, and a boundary layer grid generation algorithm is developed to generate meshes that improve the accuracy of ship resistance simulation. To validate the method, the resistances of the KRISO container ship and Japan bulk …

Aging Effects On Arterial Mechanics And Matrix Remodeling, Jie Hawes

McKelvey School of Engineering Graduate Student Theses & Dissertations

Large elastic arteries are a composite structure composed of cells and extracellular matrix proteins. Passive arterial mechanical behavior is determined by the composition of extracellular matrix proteins, in particular elastin and collagen. Elastin provides reversible elasticity to the large elastic arteries during cyclic loading and dampens the pulsatile flow from the left ventricle, reducing the workload on the heart and protecting the end organs. Disorganization and insufficiency of elastin alters the passive mechanical behavior of the large arteries. The arterial wall responds to changes in elastin organization or amount through matrix remodeling. Aging causes elastin fragmentation and degradation which changes …

Analysis The Keelung Harbor Hydrodynamic Environment For The Safety Of Navigation, Hsing-Yu Wang, Dong-Taur Su, Sung-Shan Hsiao

Journal of Marine Science and Technology–Taiwan

In this study, we simulated the hydrodynamics of the waters near the Keelung Harbor entrance and fairway before and after harbor expansion. The simulation results are used to discuss the impact of changes in the current characteristic on the inbound vessels. With reference to the fairway planning of Keelung Harbor, the simulation results before the expansion show that the current velocity with inbound fairway during the flood tide ranges from 0.08 to 1.03 m/s. Current direction was affected by the east breakwater, and a circulation occurs near the harbor entrance. After the expansion, during the flood tide, counterclockwise circulations occur …

A Machine Learning Framework For Drop-In Volume Swell Characteristics Of Sustainable Aviation Fuel, Shane Kosir, Joshua Heyne, John Graham

Mechanical and Aerospace Engineering Faculty Publications

A machine learning framework has been developed to predict volume swell for 10 non-metallic materials submerged in neat compounds. The non-metallic materials included nitrile rubber, extracted nitrile rubber, fluorosilicone, low temp fluorocarbon, lightweight polysulfide, polythioether, epoxy (0.2 mm), epoxy (0.04 mm), nylon, and Kapton. Volume swell, a material compatibility concern, serves as a significant impediment for the minimization of the greenhouse gas emissions of aviation. Sustainable aviation fuels, the only near and mid-term solution to mitigating greenhouse gas emissions, are limited to low blend limits with conventional fuel due to material compatibility issues (i.e. O-ring swell). A neural network was …

Research On Design Method Of Hull Surface Based On Reverse Engineering, Guan Guan, Wenwen Gu, Xiaole Yang

Journal of Marine Science and Technology–Taiwan

To shorten the development cycle of new ship form and improve the efficiency of ship design, this paper proposes a digital design method of hull surface based on reverse engineering. The point cloud information of the hull surface is obtained by a 3D laser scanner. The point cloud is aligned, denoised, and simplified by the improved ICP algorithm and chord height difference method. The hull surface is reconstructed in CATIA and the error analysis is performed. The smooth surface with considerable accuracy is obtained. The offsets of the reconstructed hull surface are obtained by the secondary development of CATIA. The …

New Modeling Approaches For The Prediction Of Combustion Pollutants, Phillip R. Johnson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Combustion processes are ubiquitous to human technological development and provide many benefits such as large-scale power generation for electricity and transportation along with residential and commercial heating for manufacturing, cooking, and warmth. However, these various processes can also have harmful effects on human health and the environment via emission of CO2 and other pollutants such as NOx and particulate matter (PM; often in the form of soot). For these reasons, there is a continued need for controlling, improving, and optimizing combustion processes. Modeling of these processes provides powerful insights into system-level dynamics and their control. Due to the size and …

Particle Studies In The Lab And Pilot-Scale Coal Combustion Systems, Dishant Khatri

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past century, coal contributed more to the global electricity supply than any other source. Currently, it alone accounts for over 35% of the global electricity supply. Though coal is globally well-distributed and can provide cheap, stable, and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Additionally, it is a major source of particulate matter (PM) pollution. Thus, in recent years, to reduce the impact of coal on climate, several policies have been introduced to phase out coal. However, replacing coal with intermittent renewables has led to a reduction …

Large Face Shield, Michael Stieven, Dylan Huddleston, Timothy Bragg

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The large face shield is designed to help stop the spread of COVID-19 Coronavirus in occupational environments where close contact is necessary.

Near Simultaneous Laser Scanning Confocal And Atomic Force Microscopy (Conpokal) On Live Cells, Joree N. Sandin, Surya P. Aryal, Thomas E. Wilkop, Christopher I. Richards, Martha E. Grady

Physiology Faculty Publications

Techniques available for micro- and nano-scale mechanical characterization have exploded in the last few decades. From further development of the scanning and transmission electron microscope, to the invention of atomic force microscopy, and advances in fluorescent imaging, there have been substantial gains in technologies that enable the study of small materials. Conpokal is a portmanteau that combines confocal microscopy with atomic force microscopy (AFM), where a probe "pokes" the surface. Although each technique is extremely effective for the qualitative and/or quantitative image collection on their own, Conpokal provides the capability to test with blended fluorescence imaging and mechanical characterization. Designed …

Potential Energy Generation From Agricultural Residue In Indonesia, Adrian Rizqi Irhamna

International Programs

Indonesia has great potential of biomass sources from their agricultural residue, which can potentially be used for alternative energy generation. This preliminary research explores the most suitable technology for energy generation from agricultural residue and its challenge for application in Indonesia. The study showed that biomass utilization via the direct combustion process is recommended for energy generation. It is also reported that the pretreatment process of drying and washing, are required to increase the fuel quality and plant efficiency.

Applying Renewable Energies Against Climate Change: Solar Photovoltaic (Pv) Energy, Juan Jose Estribi

International Programs

In recent years, more efforts towards fighting climate change have been done. As a direct response, research and technology have offered several insights regarding the specific causes, effects, and even possible solutions for resolving this global issue. Among these solutions, renewable energies and their potential contributions as clean energy sources can be assessed as feasible options for the energy transformation through the decarbonization process of the energy industry. This poster is mainly focused on solar photovoltaic (PV) energy and its great potential as a renewable energy by making a brief assessment of some important aspects such as resource availability, its …

Experimental Investigation Into The Boundary Layer Of A Robotic Anguilliform Propulsor, Jonathan R. Eastridge

LSU New Orleans Theses and Dissertations

Boundary layer information local to three longitudinal positions has been characterized for a 130 cm long biomimetic self-propulsor known as NEELBOT-1.1 that swims with undulatory anguilliform-like motions, via analysis of stereo particle image velocimetry (PIV) measurements for key moments in the undulation cycle and for numerous combinations of swimming conditions and motion parameters, ideal and non-ideal. No obvious turbulent flow structures or indications of boundary layer separation were observed at nonzero advance speeds, and skin friction coefficients were subsequently estimated for magnitude relative to the dynamic pressure associated with operation at the design swimming speed of U_o = 0.25 …

University Of Kentucky Measurements Of Wind, Temperature, Pressure And Humidity In Support Of Lapse-Rate Using Multisite Fixed-Wing And Rotorcraft Unmanned Aerial Systems, Sean C. C. Bailey, Michael P. Sama, Caleb A. Canter, Luis Felipe Pampolini, Zachary S. Lippay, Travis J. Schuyler, Jonathan D. Hamilton, Sean B. Macphee, Isaac S. Rowe, Christopher D. Sanders, Virginia G. Smith, Christina N. Vezzi, Harrison M. Wight, Jesse B. Hoagg, Marcelo I. Guzman, Suzanne Weaver Smith

Mechanical Engineering Faculty Publications

In July 2018, unmanned aerial systems (UASs) were deployed to measure the properties of the lower atmosphere within the San Luis Valley, an elevated valley in Colorado, USA, as part of the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE). Measurement objectives included detailing boundary layer transition, canyon cold-air drainage and convection initiation within the valley. Details of the contribution to LAPSE-RATE made by the University of Kentucky are provided here, which include measurements by seven different fixed-wing and rotorcraft UASs totaling over 178 flights with validated data. The data from these coordinated UAS flights …

Modeling And Simulation Of A Supercritical Co2-Liquid Sodium Compact Heat Exchanger For Sodium Fast Reactors, Hailei Wang, Sean M. Kissick

Mechanical and Aerospace Engineering Faculty Publications

The study focuses on modeling and simulations of sodium-sCO2 intermediary compact heat exchangers for sodium-cooled fast reactors (SFR). A simplified 1-D analytical model was developed in companion with a 3-D CFD model. Using classic heat transfer correlations for Nusselt number, some simulation results using the 1-D model have achieved reasonable match with the CFD simulation results for longer channels (i.e., 40 cm and 80 cm). However, for short channel (10 cm) when axial conduction within the sodium fluid is significant, the 1-D model significantly over-predicted the heat transfer effectiveness. By incorporating the temperature-jump model, the 1-D model can extend its …

Wireless Wearable System For The Assessment Of Gait, Abdallah Jabr

Mechanical Engineering Research Theses and Dissertations

This work investigates the development and use of a wireless wearable system for the assessment of gait. The system proposed consists of a sensor module that is attached to the foot. The sensor proposed is an inertial measurement unit, often abbreviated as IMU - a 9-axis System in Package (SiP) including a 3-axis accelerometer, a 3-axis gyroscope, and a 3-axis magnetometer, as well as a fusion engine for signal processing. While the focus of this work is on evaluating gait metrics, the performance of the proposed IMU in evaluating orientation is quantified. In doing this work, we try to address …

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …

Analysis Of Inlet Distortion Patterns On Distortion Transfer And Generation Through A Highly Loaded Fan Stage, Andrew Dallin Orme

Theses and Dissertations

Characterization of distortion transfer and generation through fans with distorted inlet conditions enables progress towards designs with improved distortion tolerance. The abruptness of transition from undistorted to distorted total pressure regions at the inlet impacts the induced swirl profile and therefore the distortion transfer and generation. These impacts are characterized using URANS simulations of PBS Rotor 4 geometry under a variety of inlet distortion profiles. A 90° and a 135° sector, both of 15% total pressure distortion, are considered. Variants of each sector size, with decreasing levels of distortion transition abruptness, are each applied to the fan. Fourier-based distortion descriptors …

On Creases And Curved Links: Design Approaches For Predicting And Customizing Behaviors In Origami-Based And Developable Mechanisms, Jared J. Butler

Theses and Dissertations

This work develops models and tools to help designers address the challenges associated with designing origami-based and developable mechanisms. These models utilize strain energy, kinematics, compliant mechanisms, and graphical techniques to make the design of origami-based and developable mechanisms approachable and intuitive. Origami-based design tools are expanded through two methods. First presented is a generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. Second is a …

The Use Of Low-Cost Sensors And A Convolutional Neural Network To Detect And Classify Mini-Drones, Austin Florio

Master's Theses

The increasing commercial availability of mini-drones and quadrotors has led to their greater usage, highlighting the need for detection and classification systems to ensure safe operation. Instances of drones causing serious complications since 2019 alone include shutting down airports [1-2], spying on individuals [3-4], and smuggling drugs and prohibited items across borders and into prisons [5-6]. Some regulatory measures have been taken, such as registration of drones above a specific size and the establishment of no-fly zones in sensitive areas such as airports, military bases, and national parks. While commercial systems exist to detect drones [7-8], they are expensive, unreliable, …

Theoretical Modeling Of Heat And Mass Transfer Processes In Phase Change And Electrochemical Energy Storage Systems, Mohammad Parhizi

Mechanical and Aerospace Engineering Dissertations - Archive

Theoretical understanding of heat and mass transfer processes in energy storage and conversion devices is of much interest for a wide variety of engineering applications. Two commonly used mechanisms for energy storage are electrochemical energy storage, such as in Li-ion cells, and phase change based energy storage, such as in phase change materials (PCM). Previous studies show that heat and mass transfer in both PCMs and Li-ion cells are critical processes affecting the performance and safety of these systems. This dissertation investigates several theoretical aspects of heat and mass transfer in these energy storage systems, with the goal of improving …

Finite Element Based Methodology To Predict Fatigue Compression Failure In Composite Based On Fiber Kinking Damage Model, Md Saddam Hossain

Mechanical and Aerospace Engineering Dissertations - Archive

Advanced polymer matrix composites are widely used in designing high-performance and lightweight spacecraft, rotorcraft, and automotive structures, due to its superior performance such as specific stiffness, specific strength, and toughness, which are appealing in reducing the weight of these structures. One critical factor that limits the efficient design of structures composed of fiber-reinforced composites (FRP) is the vulnerability of the material under compression loading since compressive strength of FRP material is typically a lot less compared to the tensile strength. Moreover, composite structure may undergo compression loading either by accidentally or by deliberately, large margins of safety are usually imposed …

A Scaling Investigation Of Feasibility And Hover Endurance For Electric Quasi Quadrotor Configurations, Budhyant Venepalli

Mechanical and Aerospace Engineering Dissertations - Archive

Motivated by recent developments in distributed propulsion electric vehicles, an effort is made in the present study to numerically investigate the upper bound of hover endurance achievable by electric quasi-quadrotors at various mass scales in the range of 0.1 kg to 10000 kg total vehicle mass. A feasible rotor propulsion pod design space is determined considering physics-based conceptual design constraints defined by blade tip Mach number and Reynolds number to ensure effective and energy-efficient generation of lift. A conceptual level scaling optimization for two-bladed rotor quasi-quadrotors was carried out at constant blade tip speed. A momentum theory model, a blade …

A Molecular Scale Study Of Cavitation Growth And Shock Response In Soft Materials, Khandakar Mahmud

Mechanical and Aerospace Engineering Dissertations - Archive

Cavitation is a mechanism through which small vapor-filled cavities are formed in a liquid medium due to rapid changes of pressure. In liquid, the cavitation bubble is created when surrounding pressure drops below the saturation vapor pressure. Here, cavitation formation due to shock wave is considered. The molecular level heterogeneous and homogenous cavitation mechanisms and bubble growth kinetics in soft gelatin hydrogel and water has been studied. Gelatin, which is derived from collagen, is frequently used as a brain simulant material. As such, the morphology of gelatin is very different from water. In the heterogeneous cavitation study, using molecular dynamics …

Experimental And Numerical Study Of Open Bath Immersion Cooling Of Microprocessors., Amirreza Niazmand

Mechanical and Aerospace Engineering Dissertations - Archive

The increase on demand of communication and networking has resulted to increase for more powerful servers and bigger data centers. With increase the power of electronics, thermal management and cooling of the equipment become a gigantic challenge due to lower surface, they have higher power density and traditional methods of cooling become ineffective. Generally, air cooling method is the first option for cooling of the electronics due to cheaper price. To increase the efficiency and capacity of cooling liquid immersion cooling is used due to higher thermal properties like heat capacity and thermal conductivity compare to air. Two methods of …

Hypoid Gear Noise And Vibration Control In Automotive Rear Axle Systems, Chia-Ching Lin

Mechanical and Aerospace Engineering Dissertations - Archive

Gear whine is a key issue for the vehicle powertrain system, and the design of a quiet, reliable driveline system is highly desirable for the automotive industry. From past studies, the main source of excitation for gear vibration and noise is the transmission error (TE), which generates the dynamic mesh force between the gear teeth. Then the vibration transmits through the flexible axle components and radiates off from the surface of the axle housing structure. The dynamic responses of the hypoid geared rotor system in the rear axle have a significant effect on the performance of noise, vibration, and harshness …

A Multiscale Study Of Cavitation Mechanism And Damage In Soft Materials, Fuad Hasan

Mechanical and Aerospace Engineering Dissertations - Archive

Cavitation is defined as the formation and growth of the gaseous bubble in bulk liquid due to the tensile pressure followed by the violent collapse. The collapse of the bubble is particularly significant due to its potential to cause damage to relatively stronger materials by either creating pressure waves (symmetric collapse) or liquid jet (asymmetric collapse). The study of cavitation in soft materials (e.g., tissue, brain, gelatin gel, etc.) has, therefore, gained a fair share of attention in the scientific communities. Recent studies have indicated that cavitation could be one of the leading causes of the mild Traumatic Brain Injury …

Molecular Level Mechanical Properties Of Ultra High Temperature Ceramics And Their Nanocomposites, Md Riaz Kayser

Mechanical and Aerospace Engineering Dissertations - Archive

Ultra High-Temperature Ceramics (UHTC) have been of great interest in the spacecraft, aerospace, and aeronautic industry due to their high melting point and their potential application as a protective material for the stagnation areas of leading edges. In this work, the effect of nanoparticle reinforcement for achieving tailored mechanical properties of UHTC’s has been studied. Two different material systems have been considered, namely the ZrB2-based and the HfO2-based nanocomposites. In the first study, the grain boundary driven mechanical behavior of polycrystalline ZrB2 and ZrC-ZrB2 nanocomposites using large-scale molecular dynamics simulations have been performed. The atomistic models of polycrystalline ZrB2 and …

Reliability Enhancement Of Heterogeneous 3d Integrated Circuit And Characterization Of Thermal Interface Material, A S M Raufur Chowdhury

Mechanical and Aerospace Engineering Dissertations - Archive

Electronic products require high functional integration in small footprints with lower cost. At the same time, it is required to maintain effective communication between the IC’s and the electronic systems. Various challenges are arising due to these factors such as signal processing time, heat dissipation, structural integrity, chip package interaction which need to be dealt effectively during electronic packaging. 3D stacking of the processors and the components accomplishes these goals and in high computing application it reduces the delay. Through-silicon via (TSV) is the heart of 3D integration, and the stacking of chips is emerging now as a powerful tool …

Experimental Investigation Of Effect Of Support Structure Geometry On The Microstructure And Metallurgical Properties Of In718 Parts Fabricated By Selective Laser Melting, Sourabh Hemant Thakare

Mechanical and Aerospace Engineering Theses - Archive

Additive Manufacturing is a modern manufacturing technique that provides extreme design freedom and the ability to manufacture multiple parts with high complexities at the same time. Various fabrication techniques have been developed, and this study focuses on selective laser melting (SLM) due to its ability to provide near-perfect parts at low cost while being able to work with a wide range of materials. In SLM, the part is manufactured, layer-by-layer, by melting and solidification of powder material under controlled inert conditions. The fabrication of complex geometries is not possible without proper allocation of support structures for the part, which keeps …

Experimental Investigation Of Laser Scan Strategy On The Microstructure, Mechanical Properties And Residual Stress Of Inconel 718 Parts Fabricated By Selective Laser Melting, Kiriti Mamidi

Mechanical and Aerospace Engineering Theses - Archive

Inconel 718 (IN718) is a nickel-based superalloy which exhibits excellent tensile and impact resistant properties along with good corrosion resistance at high temperatures. However, due to the high toughness and work hardening, the machinability of this superalloy is low. Therefore, the selective laser melting (SLM) process has been adopted as an efficient technique to fabricate IN718 parts as it overcomes the problems associated with conventional manufacturing of superalloys. SLM is a widely used additive manufacturing technique which offers the possibility to induce multi-functionality into a single component, and thus reduce the number of components that are needed. In the SLM …