Mechanical Engineering Commons^™

Design Of A Laminated Carbon Fiber I-Beam, Kyle Huber

Honors Capstones

No abstract provided.

Towards A High Bias Voltage Mems Filter Using Electrostatic Levitation, Mark Pallay, Ronald Miles, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

Traditional MEMS filters use a comb drive structure that suffers from the pull- in instability, which places a significant limitation on the achievable signal-to- noise ration of the sensor. Because the output signal from a capacitive sensor

is linearly related to the applied voltage, it is desirable to use a capacitive sensor that can withstand large voltages upwards of 100V. However, the pull-in instability causes high voltages to destroy the device and a trade-off between performance and reliability must be made. Electrostatic levitation, which works by pulling electrodes apart instead of together, eliminates the pull-in instability and allows for very …

Effects Of Polytetrafluoroethylenemicro–Particles On Mechanical Andtribological Properties Of Glass Fiberreinforced Polyoxymethylene, Kunnan Singh Jasbir Singh

Student Works (2020-2029)

Reinforcing polyoxymethylene (POM) with glass fibers (GF) enhances its mechanical properties, but at the expense of tribological performance. Formation of a transfer film to facilitate tribo–contact is compromised due to the abrasiveness of GF. As a solid lubricant, for example, polytetrafluoroethylene (PTFE) significantly improves friction and wear resistance. The effects of chemically etched PTFE micro–particles on the fiber– matrix interface of POM/GF/PTFE composites have not been systematically characterized. This research investigated the effects of PTFE micro–particles on mechanical and tribological properties of POM/GF/PTFE composites. Since PTFE is immiscible with most polymers, the surface was etched using sodium naphthalene salt dissolved …

Mechanical Properties And Microstructure Evolution Of Ti2alc Under Compression In 25–1100 °C Temperature Range, Rogelio Benitez, W. H. Kan, H. Gao, M. O'Neal, G. Proust, A. Srivastava, Miladin Radovic

Mechanical Engineering Faculty Publications

This study investigates the effects of the initial grain size and temperature (ranging from room temperature to 1100 °C) on the mechanical properties and microstructure evolution of Ti2AlC MAX phase. A Hall-Petch like relationship is observed between compressive strength and the grain size below brittle-to-plastic transition temperature (BPTT). However, the compressive strength of fine-grained MAX phase decreases more rapidly with increasing temperature resulting in inverse Hall-Petch effect above BPTT. Results from postmortem EBSD analysis reveal complex microstructural evolution in both fine- and coarse-grained microstructures during loading at different temperatures. The pronounced drop in compressive strength for fine-grained microstructures at temperatures …

Efficiency Analysis Of Harvesting Solar Energy To Perform Mechanical Work, Haden S. Bragg

Undergraduate Theses and Capstone Projects

The majority of the world’s electricity is generated using fossil fuels; in fact, the United States Energy Information Administration (EIA) states that the U.S. used fossil fuels to generate 62.7 % of its electricity in 2019 [1]. The goal of this research was to create a system that could perform mechanical work using only renewable resources. We built a solar charging station that uses two solar panels to generate electricity and an electric bicycle whose battery can be charged using the charging station. The efficiency for the type of solar cell used in this project is well established. Therefore, in …

In-Service Performance Evaluation Of Concrete Sloped End Treatments In Iowa, Jessica Lingenfelter

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

Sloped end treatments were historically developed as low-cost, low-maintenance end treatments for rigid features like concrete barriers and bridge rails. Crash testing indicated that sloped end treatments are associated with significant instability for impacting vehicles. However, the in-service performance of these features has not been evaluated. An in-service performance evaluation (ISPE) was performed to evaluate vehicle crashes with sloped end treatments in Iowa between 2008 and 2017. Researchers generated a geographic inventory of sloped end treatment locations, reviewed crash narratives and scene diagrams for crashes near these sloped end treatments, and calculated an estimated crash rate and crash cost for …

A Model For Simulation Of Convective Heat Assisted Single Point Incremental Forming Of Thermoplastics, Shubhamkar Kulkarni

All Dissertations

The overarching objective of this research is to develop a finite element model for simulation of the single point incremental forming (SPIF) process at different temperatures including convective heat assisted SPIF (CHASPIF). Single point incremental forming (SPIF) is a flexible manufacturing process with low tooling costs and times compared to thermoforming and die forming, for low production volumes. Convective heat assisted single point incremental forming (CHASPIF) is a variant of the SPIF process in which an external hot air source is used to heat the region surrounding the tool to improve formability, which can be assessed either in terms of …

Investigating The Production Of Cores By Using Reclaimed Foundry Green Sand, Kristopher Lee Boss

Dissertations and Theses @ UNI

Increasing environmental regulations, transportation cost, delivery interruptions leading to production concerns, disposal cost, and demand from other industries have influenced the way foundry’s view used sand. The purpose of this research was to determine a beneficial reuse of overflow-green sand that would normally be disposed. The reclamation process used is a combination of mechanical and wet reclamation. The focus was on the production of foundry cold box cores and if using this reclamation process could create a core with a similar quality performance compared to new sand. Research in reclamation could pave the way for a closed loop sand system, …

Hemodynamic Effects On Aortic Development Due To Outflow Tract Banding, Humza Ismail

McKelvey School of Engineering Graduate Student Theses & Dissertations

Hemodynamic forces drive remodeling of the early cardiac system in embryonic development. Perturbations of normal cardiac blood flow can cause the formation of defects and malformations within the cardiac system. Specifically, changes in hemodynamics can cause the formation of different congenital heart defects. The formation of heart defects has been studied; however, vasculature specific defects caused by changes in blood flow patterns in the early cardiac system have not been studied to the same degree. In this thesis, the effects of hemodynamic changes on arterial development were studied. Outflow tract banding (OTB) was used to cause a local increase in …

Design And Validation Of A Dynamic Pressure-Based Loading Device And 3d Strain Tracking Protocol For Ventral Hernia Modeling, Griffin Kivitz

McKelvey School of Engineering Graduate Student Theses & Dissertations

It is estimated that 350,000-500,000 ventral hernia repair surgeries are performed each year in the United States. While the long-term recurrence rate of ventral hernia repairs is not yet known, when tissues are exposed to the trauma of surgery, there is always the chance of recurrence. Commonly used ex vivo testing methods for determining the mechanical properties of the abdominal wall and biomaterials for hernia repair consist primarily of uniaxial and biaxial testing, which are not physiologically relevant loading environments. The need for a testing device that can exert physiologically relevant loads ex vivo to an abdominal wall is crucial …

Remote Radiation Sensing Using Robotic Platforms, Monia Kazemeini

UNLV Theses, Dissertations, Professional Papers, and Capstones

Remote sensing of ionizing radiation has a significant role in waste management, nuclear material management and nonproliferation, radiation safety, and accident response in situations such as the Fukushima nuclear power plant accident. Robotic platforms are able to surpass the number of tasks that could be achieved by humans. With the use of robots, the operator’s radiation exposure can be considerably decreased. Remote sensing allows for the evaluation and monitoring of radiological contamination in hazardous and hard to reach areas and locating radiation sources. In this work, gamma-ray and neutron sensors were integrated onto the unmanned aerial systems (UAS) making it …

Examining The Impact Of Student Motivation On Performance In Mechanical Engineering Design Courses, Elisabeth Kames

Theses and Dissertations

Design courses are an integral component of undergraduate engineering education. Design is recognized as one of the primary responsibilities of an engineer in industry. New designs are responsible for stimulating sales and company growth.1 This dissertation outlines a study seeking to explore the impact of student motivation factors on course performance of mechanical engineering students in design courses. The first design course, cornerstone design, takes place during the first semester of freshman year. The second course, capstone design, takes place during the student’s final year of undergraduate study. An adapted version of the Motivated Strategies for Learning Questionnaire (MSLQ) is …

Design, Analysis, And Demonstration Of A Multipurpose Fluid Tank Dynamics Characterization Platform, Cameron Ian Hume

Theses and Dissertations

The development of a highly versatile multiphase fluid tank characterization platform is essential to the analysis and improvement of propellant storage tanks. The performance of these tanks is highly critical to the safety and performance of their carriers, especially in the space industry where the propellant makes up the overwhelming majority of the mass of the vehicle. This thesis outlines the design and development of a linear stage used to test and validate the characteristic of multiphase fluids inside moving specific tanks. This document will walk through the steps taken to bring a new linear stage to life, from the …

Thermal Management Design Of A 6u Cubesat With A High-Power Additive Manufacturing Payload Using Analytical Modeling With Experimental Validation, Todd Wayne Fennell Jr.

Theses and Dissertations

As the capacity of compact battery technology for spacecraft missions continue to improve, small payloads are less constrained by power limitations, thus relatively high-power applications may be considered. AddCube is a mission to develop a platform, conforming to the 6U CubeSat Standard capable of demonstrating on-orbit Additive Manufacturing technology. A critical concern is the development and demonstration of a thermal management design that is capable of handling the significant waste heat generated by the high-power Additive Manufacturing payload while maintaining component temperatures throughout the spacecraft within an acceptable range. This effort includes a trade study for the evaluation of candidate …

Analysis Of Polyester Interleafs For Toughness Enhancement In Composite Structures, Adnan Gheryani

Theses and Dissertations

Delamination between composite layers is one of primary weaknesses in composite material structure. Various researchers have developed techniques to control delamination in laminated structures. One of these techniques is “interleaving,” adding high toughness material to key interfaces in a laminate. This research studies using polyester veil as a low-cost interleaf alternative to other materials and focuses on a non-woven, polyester spunbond material. Two different interleaf thicknesses, 0.18 mm and 0.74 mm are primarily used. In addition, fine 4 g/m2 polyester was also compared. Carbon/epoxy composites are manufactured using 2x2 Twill 24”-12k carbon fibers embedded in an epoxy resin, with polyester …

A Study On Reaction Rate Factors Of A Single-Step Combustion Mechanism For Gasoline Hcci Combustion, Pakawat Panuwatsuk

Theses and Dissertations

Homogeneous Charge Compression Ignition (HCCI) engine has been invented to achieve the advantages of both diesel and gasoline engines. HCCI engine can run with a higher compression ratio like diesel engine in order to achieve high thermal efficiency. Meanwhile, like gasoline engine, the engine produces less NOx gas and particulate matters than diesel engine. However, there are several difficulties associated with HCCI combustion, which still require further development to the engine. The most important issues are autoignition timing and narrow operational range. In order to develop an HCCI engine, a numerical simulation can significantly save cost, time and resources over …

Nonlinear Attitude Control For A 6u Cubesat With A Flexible, Deployable Boom, Jared Walker

Theses and Dissertations

A satellite attitude control system was developed in MathWork’s Simulink for a 6U CubeSat with a flexible appendage payload. The flexible appendage is a boom that is able to store into a compact size and deploy out to 1 meter. The boom deploys a sensor attached to the end of the boom. The boom/sensor payload was modeled as a spring-mass-damper system. The equivalent spring constant of the payload was determined by the the natural frequency of the system. A modal analysis in ANSYS Mechanical was used to determine the natural frequencies and mode shapes of the payload. The attitude control …

Living Docks: Structural Implications And Determination Of Force Coefficients Of Oyster Mats On Dock Pilings In The Indian River Lagoon, Ryan Christiansen

Theses and Dissertations

Brevard County, Florida, is facing rapid population growth and increased pollution entering the Indian River Lagoon (IRL), impairing water quality and damaging the ecosystem. This is problematic not only for public health and environmental stability, but also for the economy. The Living Docks initiative was created to combat environmental degrade in the lagoon and restore natural functions back to the ecosystem. With increased urbanization along coastal systems, there is opportunity for new forms of ecological engineering such as Living Docks, which attaches oyster mats to dock pilings as a means to promote the growth of filter feeding organisms. It is …

Design Of An Environmentally Responsive Grooming Tool To Aid In Underwater Navigation, Bruce Huntress Walker Iii

Theses and Dissertations

Underwater hull grooming is a proactive approach to ship hull husbandry. It has been defined as the frequent and gentle wiping of a ship hull coating to maintain it free of fouling. One of the challenges to implementing a grooming schedule is the control and navigation of the devices over the surface of the hull. This thesis presents prior research that has developed self-attaching rotating brushes as an effective method to groom fouling control coatings and the results from several years of implementation in the marine environment. The hypothesis of this thesis is that the condition of the ship hull …

Impact Of Part Thickness And Drying Conditions On Saturation Limits In Binder Jet Additive Manufacturing, Nathan B. Crane

Faculty Publications

Binder jetting (BJ) is a high build-rate additive manufacturing process with growing commercial interest. Growth in BJ applications is driven by the use of finer powders and improved post-processing methods that can produce dense, homogenous final parts. However, understanding of the basic droplet/powder interaction is relatively limited. This paper considers the impact of in-process drying, part geometry, and droplet size on a key printing parameter: binder saturation. Parts of varying thicknesses are printed with a range of saturation levels under various heating conditions. The ratio of the printed part mass to the theoretical part mass is used to detect bleeding. …

Chlorine Removal From U.S. Solid Waste Blends Through Torrefaction, Zhuo Xu, Josh W. Albrecht, Shreyas Kolapkar, Stas Zinchik, Ezra Bar Ziv

Michigan Tech Publications, Part 1

The amount of solid waste generated annually is increasing around the world. Although the waste has a high calorific value, one major obstacle that may prevent it from becoming a feedstock for power applications is the existence of polyvinyl chloride (PVC), which causes corrosion and emission issues after combustion due to its high chlorine content. Torrefaction is known to release hydrochloric acid; thus, it has been applied in this study for the reduction of chlorine from potential waste feedstocks. Fiber-plastic (60-40%) waste blends, with different chlorine content levels, as well as PVC were used in the current study. Torrefaction was …

Enhancement Of Phase Change Material Sorbitol By Nanoparticle Inclusion For Improving Thermal Energy Storage Capabilities, Joshua Kasitz

Mechanical Engineering Undergraduate Honors Theses

Thermal management of electronic devices has become an increasingly vital field of study with the rapid miniaturization of many key electrical components. With the significant improvement of semiconductor manufacturing and intensified focus on interconnects, electronic devices have decreased in size at an incredible rate. Decreasing spatial requirements is essential to improving device capabilities as the electronic system is able to incorporate more components. Currently, electronic systems are drastically limited by the capabilities of their cooling mechanisms. Smaller devices lead to large increases in the energy density of the system and require more powerful cooling systems to maintain proper component operating …

Target Control Of Networked Systems, Isaac S. Klickstein

Mechanical Engineering ETDs

The control of complex networks is an emerging field yet it has already garnered interest from across the scientific disciplines, from robotics to sociology. It has quickly been noticed that many of the classical techniques from controls engineering, while applicable, are not as illuminating as they were for single systems of relatively small dimension. Instead, properties borrowed from graph theory provide equivalent but more practical conditions to guarantee controllability, reachability, observability, and other typical properties of interest to the controls engineer when dealing with large networked systems. This manuscript covers three topics investigated in detail by the author: (i) the …

3d-Printed Biomimetic Bioactive Glass Scaffolds For Bone Regeneration In Rat Calvarial Defects, Krishna C. R. Kolan, Yue-Wern Huang, Julie A. Semon, Ming-Chuan Leu

Biological Sciences Faculty Research & Creative Works

The pore geometry of scaffold intended for the use in the bone repair or replacement is one of the most important parameters in bone tissue engineering. It affects not only the mechanical properties of the scaffold but also the amount of bone regeneration after implantation. Scaffolds with five different architectures (cubic, spherical, x, gyroid, and diamond) at different porosities were fabricated with bioactive borate glass using the selective laser sintering (SLS) process. The compressive strength of scaffolds with porosities ranging from 60% to 30% varied from 1.7 to 15.5 MPa. The scaffold's compressive strength decreased significantly (up to 90%) after …

Emissivity Measurements Of Painted And Aerosol Deposited Thermographic Phosphors (Yag:Dy And Mfg:Mn), Wendy Flores-Brito

Mechanical Engineering ETDs

Combustion is one of the most difficult processes to model. Luminous flames are characteristically sooty, which creates a problem when modeling and calculating the combustion and heat transfer of the process; both of which are highly dependent on temperature and emissivity. Soot particle emissivity as well as gas contributions affect the heat transfer calculation and must be accounted for.

Thermographic phosphors (TP) are ceramic based phosphorescent materials that have a temperature dependent emission that can be exploited to obtain surface and gas temperature measurements, as well as 2D temperature maps. Emissivity knowledge is not needed to obtain temperature and is …

Development Of A Novel Vehicle Guidance System: Vehicle Risk Mitigation And Control, Michael Sweigard

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

Over a half of fatal vehicular crashes occur due to vehicles leaving their designated travel lane and entering other lanes or leaving the roadway. Lane departure accidents also result in billions of dollars in cost to society. Recent vehicle technology research into driver assistance and vehicle autonomy has developed to assume various driving tasks. However, these systems are do not work for all roads and travel conditions. The purpose of this research study was to begin the development a novel vehicle guidance approach, specifically studying how the vehicle interacts with the system to detect departures and control the vehicle

A …

Evaluation And Update Of Mash Test Vehicles, Kellon B. Ronspies

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

The Manual for Assessing Safety Hardware (MASH) requires full-scale crash testing of roadside features using worst practical impact conditions. Vehicle selection for full-scale crash testing is intended to be representative of the contemporary passenger vehicle fleet. Researchers at the Midwest Roadside Safety Facility (MwRSF) investigated attributes of passenger vehicle sales to determine if the vehicle selection criteria shown in MASH should be revised to accommodate changes in the vehicle fleet. A methodology was considered to affordably re-analyze the vehicle fleet when necessary to ensure MASH vehicle selection criteria are reflective of vehicles currently on roadways.

Representative vehicles were documented using …

Change Of Exposure Time Mid-Test In High Temperature Dic Measurement, Thinh Quang Thai, Adam J. Smith, Robert J. Rowley, Paul R. Gradl, Ryan B. Berke

Mechanical and Aerospace Engineering Faculty Publications

Performing digital image correlation (DIC) at extreme temperatures has been greatly challenging due to the radiation which saturates the camera sensor. At such high temperatures, the light intensity emitted from an object is occasionally so powerful that the acquired images are overwhelmingly saturated. This induces data loss, potentially ruining the test, thus requiring the user to restart the test. For this reason, selection of an appropriate camera sensitivity plays a crucial role prior to beginning the test. Exposure time is a factor contributing to camera sensitivity and it is the easiest setting to manipulate during the test since it introduces …

Designing An Adjustable And Transportable Staircase, Allison Currey

Undergraduate Honors Thesis Projects

People climb stairs every day, whether it is at work, a store, or at home; however, there are populations such as people who are elderly, with pathologies, with Parkinson’s disease, or have suffered from a stroke that see climbing the stairs as a challenging task and it decreases their mobility and quality of life. Factors such as muscle weakness, strategy, and balance have been previously investigated in these populations during stair climbing. However, few studies have researched how stair climb ability, balance, and perception of difficulty are influenced by step height. The objective of this thesis is to design a …

Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The reputation of low-moisture foods as safe foods has been crumbling over the past decade due to repeated involvement in foodborne illness outbreaks. Although various pasteurization technologies exist, a majority are thermal processes and have not been well-characterized for pasteurizing low-moisture foods. In addition, the nature of a low-moisture food matrix introduces various experimental complications that are not encountered in high-moisture foods. In this dissertation, the development, building instructions, and characterization of various open source tools for studying the inactivation kinetics of microorganisms in low-moisture foods are described. The first tool is the TDT Sandwich, a dry heating device for …