Mechanical Engineering Commons^™

Power And Voltage Modelling Of A Proton-Exchange Membrane Fuel Cell Using Artificial Neural Networks, Tabbi Wilberforce, Mohammad Biswas, Abdelnasir Omran

Mechanical Engineering Faculty Publications and Presentations

A proton exchange membrane fuel cell (PEMFC) is a more environmentally friendly alternative to deliver electric power in various applications, including in the transportation industry. As PEMFC performance characteristics are inherently nonlinear and involved, the prediction of the performance in a given application for different operating conditions is important in order to optimize the efficiency of the system. Thus, modelling using artificial neural networks (ANNs) to predict its performance can significantly improve the capabilities of handling the multi-variable nonlinear performance of the PEMFC. However, further investigation is needed to develop a dynamic model using ANNs to predict the transient behavior …

Energy Consumption Analysis Using Measured Data From A Net-Zero Energy Commercial Building In A Cold And Dry Climate, Sukjoon Oh, John F. Gardner

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Zero-energy buildings have a critical role in reducing global energy use and greenhouse gas emissions. However, few studies have analyzed net-zero energy commercial buildings using measured energy use such as whole-building level and end-use level data. This paper presents an energy consumption analysis for the first net-zero energy commercial building in Idaho, U.S., in a cold and dry climate using measured end-use data from this building as well as measured whole-building energy use. Monthly bill data analysis, end-use data analysis, and Energy Use Intensity (EUI) analysis were conducted. The combined analysis of this study shows that the HVAC system was …

Out-Of-Plane Load-Bearing And Mechanical Energy Absorption Properties Of Flexible Density-Graded Tpu Honeycombs, Ibnaj Anamika Anni, Kazi Zahir Uddin, Nicholas Pagliocca, Nand Singh, Oyindamola Rahman, George Youssef, Behrad Koohbor

Henry M. Rowan College of Engineering Departmental Research

Honeycomb structures are widely used in applications that require excellent strain energy mitigation at low structural weights. The load-bearing and energy absorption capacity of honeycomb structures strongly depend on their cell wall thickness to edge ratios. This work studies the mechanical response and strain energy absorption characteristics of hexagonal honeycomb structures with various cell wall thicknesses in response to out-of-plane loading conditions. Honeycomb structures with various nominal densities are first additively manufactured from flexible thermoplastic polyurethane (TPU). A comprehensive experimental study characterized the mechanical strength, energy absorption performance, and the strain recoverability of the structures. Density-graded structures are then fabricated …

Data-Driven Research On Engineering Design Thinking And Behaviors In Computer-Aided Systems Design: Analysis, Modeling, And Prediction, Molla Hafizur Rahman

Graduate Theses and Dissertations

Research on design thinking and design decision-making is vital for discovering and utilizing beneficial design patterns, strategies, and heuristics of human designers in solving engineering design problems. It is also essential for the development of new algorithms embedded with human intelligence and can facilitate human-computer interactions. However, modeling design thinking is challenging because it takes place in the designer’s mind, which is intricate, implicit, and tacit. For an in-depth understanding of design thinking, fine-grained design behavioral data are important because they are the critical link in studying the relationship between design thinking, design decisions, design actions, and design performance. Therefore, …

Geometric Analysis Of Insect Wing Vein Network, Jacob White, Ying Hu, Sangjin Ryu, Seunghee Kim, Haipeng Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

An insect wing consists of a thin membrane supported by a system of veins, and flow of blood through the system of veins is critical for maintaining healthy insect wings. Better understanding of the insect wing vein circulation requires to know how the efficiency of blood flow in an insect wing relates to the geometric shape of the vein. Our investigation of the wing vein network of a dragonfly Anax junius follows the idea of Murray’s law, which is established in the study of efficiency of the vein network and the geometric shape of the vein. Instead of using the …

Infrared And Fluorescent Thermal Imaging And Thermal Transport Characterization Of Engineering Devices And Systems, Swapnil Suryakant Salvi

Mechanical and Aerospace Engineering Dissertations - Archive

Infrared (IR) thermal imaging is widely used for non-contact temperature measurement in engineering. IR camera detects thermal emissions from the target surface in a certain wavelength range, which, using the known surface emissivity, can be converted to a pixel-by-pixel temperature map. Fluorescence imaging also works along similar lines. This Ph.D. dissertation contributes towards thermal imaging and thermal transport characterization in engineering devices/systems using infrared and fluorescence imaging. In the first two parts of this work, infrared thermal imaging is used for measuring thermal conductivity of thin wires and for spotting unusual activities in a three-dimensional integrated circuit (3D IC). In …

In-Situ Observation Of Extrusion Process In Thermoplastic Material Extrusion Based Additive Manufacturing, Ye Hong

Mechanical and Aerospace Engineering Dissertations - Archive

In thermoplastic material extrusion-based additive manufacturing, solid polymer filaments are fed into extruders to generate extrudates that are needed to build 3D plastic products. There is a finite gap between the inner surface of an extruder and the edge of a filament. This gap facilitates the insertion and translation of the filament inside the extruder. However, it is still not clear how the gap is filled during the extrusion. The lack of this information makes it difficult to model the temperature distribution and flow profile during the extrusion. In this work, we built experimental apparatus to directly observe the gap-filling …

Multi-Objective Aero/Mechanical Design Optimization Of Gp Turbine Blades Platform Contour Using Adjoint Solver And Impact On Secondary Losses, Mostafa Soliman

Mechanical and Aerospace Engineering Dissertations - Archive

Gas Turbines Hot Gas Path components represent the major contribution to generating power in Gas Turbines They are the components that mainly extract power from hot gasses that come out of the combustion Chamber (Combustor). Due to harsh temperature and environment, these components are vulnerable to high thermal and mechanical stresses which affect its durability, life, and efficiency. Hot Gases go through these components can reach very high max temperature. Max blade alloy metal temp in Gas Path blades can reach 1800-1900 F. Because of these severe operation conditions, a very careful prediction of stresses, thermal distribution, losses and flow …

Cold Plate Based Dynamic Liquid Cooling At Data Center And Chip Level, Pardeep Shahi

Mechanical and Aerospace Engineering Dissertations - Archive

The rising demand for high-performance central and graphical processing units has resulted in the need for more efficient thermal management techniques like direct-to-chip liquid cooling. Direct Liquid Cooling using cold plates is one of the most efficient and investigated cooling technology since the 1980s. Major data and cloud providers like IBM, Microsoft, and Google are actively deploying liquid-cooled data center infrastructure due to rising computational demands but its performance and efficiency can be further be enhanced using dynamic cooling technologies. At the chip level since the early ’60s, based on Moore’s law, transistor density has been doubling every generation resulting …

Interactions Of Vortices With Differing Creation Mechanisms In The Wake Of A Normal Flat Plate-Delta Flat Plate Couple: A Numerical Study., Cheruvateth Vivek Nair

Mechanical and Aerospace Engineering Dissertations - Archive

ABSTRACT: Fluid flow is characterized by the presence of various coherent vortical structures such as vortex tubes, vortex streets, and eddies. When these vortical structures interact with each other or other distinct mechanisms in a fluid, they form a chaotic region of mixing where a large transfer of mass and energy is observed; This phenomenon is called a vortex interaction and is commonly observed in nature across large Reynolds number regimes. In engineering, vortex interactions are an important topic of research in areas such as mixing, flow induced vibrations, propulsion, aerodynamics, convection, heat island effects, hydrodynamics, and atmospheric Sciences, to …

Fixed Wing Aircraft Collision Avoidance Using Collision Cone Theory, Andrew T. Iii Beary

Mechanical and Aerospace Engineering Theses - Archive

This thesis develops the guidance and control components of an aircraft collision avoidance system, using a collision cone-based approach. These guidance and control laws are developed by considering the nonlinear relative kinematic equations of the aircraft that are on a collision course, as well as the nonlinear flight dynamics of the aircraft performing the collision avoidance maneuver. The longitudinal and lateral-directional axes of the aircraft are considered separately. The developed guidance and control laws are subsequently integrated with the nonlinear aircraft dynamics in a MATLAB/Simulink framework, and simulations performed to demonstrate the working of the overall system.

Reactive Motion Planning Of Autonomous Vehicles In 3-Dimensional Environments Using Collision And Rendezvous Cones, Kashish Dhal

Mechanical and Aerospace Engineering Dissertations - Archive

This dissertation presents a collision cone/rendezvous cone-based approach for reactive motion planning in three-dimensional dynamic environments. Collision avoidance is fundamental to robot motion planning. In dynamic environments, the path and velocities of obstacles are not known a-priori, and hence it is a common practice to use reactive planners. Reactive planners should be computationally inexpensive because they need to act fast to avoid potential collisions. To reduce the computational load, a majority of motion planning algorithms model the shapes of the robots and obstacles as a circle/sphere. However, when the objects are elongated more in one direction than another, the spherical …

Foundations For Finite-State Modelling Of A Two-Dimensional Airfoil That Reverses Direction, Jake Michael Oscar Welsh

McKelvey School of Engineering Graduate Student Theses & Dissertations

Current 3-D finite-state wake models are incapable of simulating a maneuver in which the sign of the free-stream velocity changes direction and the rotor enters its own wake -- as might occur in the case of a helicopter which ascends and then descends. It is the purpose of this work to create a 2-D finite-state wake model which is capable of handling changes in free-stream direction as a precursor to development of a 3-D model that can do the same.

The 2-D finite-state model used for reentry modifications is an existing model created by Peters, Johnson, and Karunamoorthy. By the …

Impact Of Spray Coating On The Performance Of Hydrophobic Membranes, Dominick J. Maiorano, Hamid Fattahijuybari, David Warsinger

Discovery Undergraduate Interdisciplinary Research Internship

Membrane distillation (MD) is a rapidly emerging water treatment technology used to combat the global water crisis. Membrane pore wetting is a primary barrier to widespread industrial use of MD. The primary causes of membrane wetting are membrane fouling and an exceedance of liquid entry pressure. The development of different types of polymer membranes and the use of pretreatment have led to significant movement towards the prevention of wetting in MD. We sought to take a new approach to combat membrane wetting that involves coating these membranes with hydrophilic chemical compounds, which consequently would decrease their air permeability. Pulling data …

Novel Patterning Techniques To Improve Digital Image Correlation In Challenging Environments, Weston Craig

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A camera-based measurement technique called digital image correlation (DIC) is beneficial to measure displacement and strain in challenging environments (such as post-irradiation evaluation and high temperature environments) due to its non-contacting nature and ability to obtain measurements over multiple length scales. This technique requires a surface pattern which influences the measurement resolution and accuracy of the measurements. This thesis explores two novel patterning techniques to allow the use of DIC in more challenging environments:

The first is to determine if a pattern created from printed text can be used as a pattern in DIC. Native patterns are patterns already present …

Peridynamic Modeling Of Crack Propagation In Brittle Materials With Electromechanical Coupling, Semsi Coskun

Dissertations

The bond-based peridynamics (BB-PD) is a widely used peridynamic model in the literature. Despite Poisson's ratio restriction, it still serves as a powerful tool to solve challenging engineering problems with a relatively cheap computational cost. Consider the Poisson ratio of the material does not deviate from the ones that BB-PD can model. In that case, it becomes advantageous to use the BB-PD compared to other PD models in terms of computational cost and simplicity. However, the BB-PD suffers from the so-called surface or skin effect where the material response at boundaries becomes softer than the bulk material points. As a …

Collaborative Robotics Strategies For Handling Non-Repetitive Micro-Drilling Tasks Characterized By Low Structural Mechanical Impedance, Xiangyu Wang

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanical micro-drilling finds widespread use in diverse applications ranging from advanced manufacturing to medical surgery. This dissertation aims to develop techniques that allow programming of robots to perform effective micro-drilling tasks. Accomplishing this goal is faced with several challenges. Micro-drills suffer from frequent breakage caused from variations in drill process parameters. Micro-drilling tasks afford extremely low feed rates and almost zero tolerance for any feed rate variations. The accompanying robot programming task is made difficult as mathematical models that capture the micro-drilling process complexities and sensitive variations in micro-drill parameters are highly difficult to obtain. Therefore, an experimental approach is …

A Comparison Of Uniaxial Compressive Response And Inelastic Deformation Mechanisms In Freeze Cast Alumina-Epoxy Composites Without And With Rigid Confinement, Tareq Aljuhari

Mechanical & Aerospace Engineering Theses & Dissertations

Cellular ceramics have an array of improved mechanical properties that make them incredibly desired for different applications such as armor systems, aircraft structures, automobiles bumpers, and biomedical implants. It is also desirable that porous architecture could be shaped into bulk complicated shapes and easy to scale-up with low manufacturing cost. Despite several efficient techniques to fabricate cellular ceramics, some limitations are preventing us from meeting the high demand of the after mentioned applications. For that, freeze casting, also called ice-templating, is technique of solidifying an aqueous ceramic suspension under the effect of unidirectional temperature gradient. In this study, Ice-templated porous …

Mechanizing The Removal Of Soil Between Peach Trees Planted On Berms, Coleman Scroggs

All Theses

Armillaria root rot (ARR), primarily caused by the soilborne fungus Desarmillaria tabescens, has become the number one cause for peach tree decline in the Southeastern United States. Research has shown that planting peach trees on shallow berms and excavating the soil around the root collar two years after planting lessens the effects of ARR. However, berms make orchard operations such as pruning, thinning, and harvesting more cumbersome and cause cultural concerns as channels of water at their base can lead to erosion and the slope of the berms leads to herbicide and fertilizer runoff. The objective of this research was …

Multi-Sensor Signatures From Ultrasonic Wire Embedding Used In Hybrid Additive Manufacturing, Patrick Steven Gutierrez

Open Access Theses & Dissertations

Additive Manufacturing (AM) has matured such that its products are used in applications ranging from prototypes to end-use parts; however, to expand the adoption of AM, the inclusion of multiple manufacturing technologies has become a focus area especially when the result is a 3D printed part with an embedded electrical system. The W.M. Keck Center for 3D Innovation has developed the Foundry Multi3D system consisting of two material extrusion AM machines, a robotic arm, and a CNC machine equipped with a laser soldering tool, solder micro-dispensing tool and an ultrasonic wire embedding (USWE) tool. The focus of this paper is …

Piezoelectric Point-Of-Care Biosensor For The Detection Of Sars-Cov-2 (Covid-19) Antibodies, Debdyuti Mandal, Mustahseen M. Indaleeb, Alexandra Younan, Sourav Banerjee

Faculty Publications

It is always challenging to diagnose a disease using a biosensor reliably, and quickly with high sensitivity and selectivity, simultaneosuly. Recently the world experienced a global pandemic caused by a novel coronavirus (COVID-19). Although the vaccines are available, COVID-19 resulted a huge threat to the entire world with high mortality rates. Irrespective of a specific disease, there is a constant need for a cheaper and faster in-vitro, lab-on-a-chip sensor with high sensitivity and selectivity. Such sensors will not only facilitate the disease detection but will expedite and vaccine development process through detection of its corresponding antibodies when developed. In this …

Effects Of Imu Sensor Location And Number On The Validity Of Vertical Acceleration Time-Series Data In Countermovement Jumping, Dianne Althouse

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Many devices are available for measuring the height of a CMJ. An inertial measurement unit (IMU) measures linear acceleration, orientation, and angular velocity. As an alternative to using IMU estimates of flight time, CMJ height could be estimated by integrating the IMU time-series signal for vertical acceleration to derive CMJ take-off velocity in order to track whole-body center of mass (WBCoM) movement, yet this approach would require valid IMU acceleration data. Thus, the purpose of this study was to quantify the effects of IMU sensor location and number on the validity of vertical acceleration estimation in CMJ. Thirty young adults …

A Modification To The Skiving Process For The Manufacture Of Offset Geometry Strip-Fin Heat Sinks, Daniel Luberda

McKelvey School of Engineering Graduate Student Theses & Dissertations

High-powered electronics are extremely prevalent, and a vast majority of these devices use some form of heat sinks as either an active or passive cooling device. Although two-phase cooling technology has rapidly advanced to accommodate increasing heat loads on modern electronics, the added costs and complication inherent in two-phase cooling solutions makes effective air-cooled heat sinks potentially valuable.

A more effective heat sink can occupy a smaller footprint to dissipate the same heat flux, meaning material and packaging costs can be reduced. Aluminum heat sinks are produced through a variety of manufacturing processes, including machining, bonding, extrusion, casting, forging, 3D …

Smart Manufacturing—Theories, Methods, And Applications, Zhuming Bi, Lida Xu, Puren Ouyang

Information Technology & Decision Sciences Faculty Publications

(First paragraph) Smart manufacturing (SM) distinguishes itself from other system paradigms by introducing ‘smartness’ as a measure to a manufacturing system; however, researchers in different domains have different expectations of system smartness from their own perspectives. In this Special Issue (SI), SM refers to a system paradigm where digital technologies are deployed to enhance system smartness by (1) empowering physical resources in production, (2) utilizing virtual and dynamic assets over the internet to expand system capabilities, (3) supporting data-driven decision making at all domains and levels of businesses, or (4) reconfiguring systems to adapt changes and uncertainties in dynamic environments. …

Characterization Of Fatigue Strength Of Additively Manufactured Ti-6al-4v With Recoater Blade Interference Flaws And Residual Stresses Towards An Enhanced Fatigue Substantiation Methodology For Aerospace Structures Applications, Joshua Manyara Mochache

Mechanical and Aerospace Engineering Dissertations - Archive

This research characterized the fatigue strength of additively manufactured (AM) Ti-6Al-4V, through fatigue and static tests conducted using specimens with and without recoater blade interference flaws (RBIF), and thus further enhanced the fatigue substantiation methodology for AM parts by using combined fatigue strength knock-down-factors (KDF) developed from this study. Qualification and certification (Q&C) of metallic AM parts, through acceptable methods for fatigue and damage tolerance (F&DT) substantiation, is an area where significant gaps still exist. While progress has been made in design as well as materials and process standardization, Q&C of additively manufactured metallic structural parts, especially those in civil …

Development Of A Reverse Engineered, Parameterized, And Structurally Validated Computational Model To Identify Design Parameters That Influence American Football Faceguard Performance, William Ferriell

All Dissertations

Traumatic brain injury (TBI) continues to have the greatest incidence among athletes participating in American football. The headgear design research community has focused on developing accurate computational and experimental analysis techniques to better assess the ability of headgear technology to attenuate impacts and protect athletes from TBI. Despite efforts to innovate the headgear system, minimal progress has been made to innovate the faceguard. Although the faceguard is not the primary component of the headgear system that contributes to impact attenuation, faceguard performance metrics, such as weight, structural stiffness, and visual field occlusions, have been linked to athlete safety. To improve …

Aerodynamics And Vibrations Of A Helicopter Rotor Blade, Mohammad Khairul Habib Pulok

LSU New Orleans Theses and Dissertations

The nature of the aerodynamic environment surrounding a helicopter causes a significant amount of vibration to its whole body. Among different sources of vibrations, the aerodynamic loading on the main rotor blade is the major contributor. Therefore, analyzing a rotor blade's vibration characteristics and aerodynamic behavior becomes essential. The vortex characteristics and the wake surrounding a helicopter rotor blade play an important role because they affect the aerodynamic behavior of the rotor blade. An advanced mathematical and computational model of rotor wake and blade vortex gives a better understanding of the helicopter rotor dynamics. This study develops computational models of …

A Lacunarity-Based Index For Spatial Heterogeneity, Ryan H. Scott, Hawwa Falih Kadum, G. Salmaso, Marc Calaf, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Characteri zing spatial heterogeneity is fundamental in numerous areas, yet defining spatial patterns often depends on qualitative assessments or a priori knowledge. Lacunarity analysis is a popular occupancy-based method for identi fy ing relevant length scales in spatially heterogeneous systems. From lacunarity, we identify the ex istence of a point which encapsulates the spatial heterogeneity of a given system. This value sati sfies the conditions for the lac unarity cutoff function and forms the bas is of a heterogeneity index. We evaluate the behavior of both parameters in mono fractal, clustered, and periodic systems. ln addition, we demonstrate the broad …

Predicting The Impact Of Utility Lighting Rebate Programs On Promoting Industrial Energy Efficiency: A Machine Learning Approach, Phillip Shook, Jun-Ki Choi

Mechanical and Aerospace Engineering Faculty Publications

Implementation costs are a major factor in manufacturers' decisions to invest in energy-efficient technologies. Emerging technologies in lighting systems, however, typically require small investment costs and offer short, simple payback periods, due, in part, to federal, state, and utility incentive programs. Recently, however, certain state and federal mandates have reduced the support for and efficacy of electricity utility incentivizing programs. To determine the impact of such support programs, this study examined historical data regarding lighting retrofit savings, implementation costs, and utility rebates gathered from 13 years of industrial energy audits by a U.S. Department of Energy Industrial Assessment Center in …

Design, Microfabrication And Characterization Of Vibrating Mesh Atomizer For Viscous Fluids, Pallavi Sharma

Mechanical Engineering ETDs

This research focuses on a new piezoelectrically driven Micro Electromechanical Systems based vibrating mesh atomizer that generates the pressure differential required for droplet ejection or spray production using frequency resonances in the 100 kHz range. This study involves device construction and experimental characterization to comprehend the device's operation and the influence of various factors on its performance and determine the limitations of a range of working fluids to atomize.

A novel approach to integrating polymer-based micro heaters with a vibrating mesh atomizer as a monolithic component is presented to expand the range of working liquids for the MEMS device. The …