Mechanical Engineering Commons^™

Comparative Analysis Of Command Protocols For Cubesat Data Handling Systems, Roman Dowling

Mechanical Engineering Undergraduate Honors Theses

Researchers at the University of Arkansas developed ARKSAT-1, a cubic satellite with the purpose of employing an LED with a tracking system to perform spectroscopic measurements of the atmosphere.

The control board of the satellite contained several microcontrollers which worked in concert to collect and manage data. Discussed in this report are the software programs developed for the microcontrollers, dual Arduino MKRZeros, utilized as data repositories and for control of satellite peripherals. The programs discussed in this project include an original existing command-response protocol and an improved batch-command protocol, each with its accompanying data handling and storage system. These programs …

Thermal Resistance Characterization Of High-Voltage Sic Power Module, Landon Lemmons

Mechanical Engineering Undergraduate Honors Theses

Researchers within the University of Arkansas Electrical Engineering Research Department have embarked on a project aimed at enhancing the thermal performance of high-voltage power modules. To aid in the progress of this project, the design, and development of a thermal tester device are needed. The primary objective of this device is to determine the various thermal properties of high-voltage power modules that the electrical engineering department has developed. Additionally, the project aims to facilitate electrical loading tests on power modules and provide researchers with the means to calibrate the power module in terms of thermal load. This project also possesses …

Autonomous Material Refill For Swarm 3d Printing, William C. Jones

Mechanical Engineering Undergraduate Honors Theses

3D printing currently offers robust and cheap rapid prototyping solutions. While standard 3D printing remains at the periphery of mass production, the technology serves as a starting point for the development of swarm manufacturing. Since swarm manufacturing is predicated upon autonomy, swarm technology companies such as AMBOTS are seeking to minimize human involvement in the swarm’s functions. At present, the 3D printing swarm consists of the printers, a transporter which can take them between job sites, and the floor tiles which provide power and support the build surfaces. To add to this ecosystem, this project is focused on the design …

Designing Cryogenic Strain Device For 2d Materials, Jake Carter

Mechanical Engineering Undergraduate Honors Theses

The Churchill lab working within the Physics Department at the University of Arkansas is working to create important quantum states including weak topological insulators (TIs) through the use of symmetry engineering and topological electronic states in two-dimensional (2D) crystals of WHM materials. Experimental results of these topological states have been obstructed due to the difficulty to perform controlled in situ strain. This project strives to create a mount to utilize a piezoelectric nanopositioner within cryostats achieving an in situ strain that creates the quantum states the lab is looking to observe. This report also examines the necessary equations to determine …

Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher

Mechanical Engineering Undergraduate Honors Theses

Diamond-like carbon (DLC) coatings have a wide array of desirable characteristics such as low friction, high hardness, and scratch resistance. Due to high residual stress and thermal mismatch, DLC films experience adhesion difficulties when bonded with metallic substrates, leading to cracking and delamination. In this study, the properties of a new coating with a polydopamine underlayer and silica nanoparticles bonded to a stainless-steel substrate (PDA+SiO2/DLC) were studied alongside three other samples, one with a polydopamine underlayer (PDA/DLC), one with a trimethylsilane (TMS) underlayer (TMS/DLC), and one with no underlayer (DLC only). Nanoscratch tests were performed with a 1 μm spheroconical …

Improving The Performance Of An Ead Aircraft By Use Of A Retractable Electrode System, Michael Alexander Fredricks

Mechanical Engineering Undergraduate Honors Theses

Electroaerodynamic (EAD) propulsion is a growing area of research for small, low powered aircraft. Recent tests of EAD aircraft have demonstrated low performance in unpowered, gliding flight. The purpose of this paper is to investigate the effect of a retractable electrode system on the flight performance of an EAD aircraft. An analysis of electrode drag contribution on the MIT ionic wind plane’s performance predicts a maximum lift to drag ratio of 22, with the addition of a retractable electrode system, for a similarly sized and modeled EAD aircraft. An experiment is developed using a prototype aircraft, launcher, and retraction system …

Design And Control Of A Peristaltic Pump To Simulate Left Atrial Pressure In A Conductive Silicone Model, Jeremy Collins

Mechanical Engineering Undergraduate Honors Theses

According to the CDC, atrial fibrillation is responsible for more than 454,000 hospitalizations and approximately 158,000 deaths per year. A common treatment for atrial fibrillation is catheter ablation, a process in which a long flexible tube is guided through the femoral artery and to the source of arrhythmia in the heart, where it measures the electrical potential at various locations and converts problematic heart tissue to scar tissue via ablation. This paper details the design and control of a low-cost ($400) peristaltic pump system using repetitive control to replicate blood pressure in the left atrium in a conductive silicone model …

3d Printing A Microfluidic Chip Capable Of Droplet Emulsion Using Ninjaflex Filament, Robert Andrews

Mechanical Engineering Undergraduate Honors Theses

This paper details an investigation into methods and designs of 3D printing a microfluidic system capable of droplet emulsion using NinjaFlex filament. The specific field in which this paper’s experiment is rooted is dubbed “BioMEMS,” short for bio microelectromechanical systems. One prominent research area in BioMEMS is developing a “lab on a chip.” Essentially, the goal is to miniaturize common lab processes to the micro scale, rendering it possible to include these processes in a small chip. Reducing necessary sample sizes, shortening the reaction times of lab processes, and increasing mobility of lab processes can all be realized through microfluidic …

Design Of A Scara Based Mobile 3d Printing Platform, Zachary Hyden

Mechanical Engineering Undergraduate Honors Theses

Currently 3D printers rely heavily on people to run them, there is no automatic way to start a new print after one has finished. On top of this 3D printers are limited in the area they can print on. Even though the additive manufacturing market is rapidly growing and is increasingly being used in product manufacturing there has yet to be a solution to this problem. This research proposes using mobile 3D printing robots to solve both of these issues. The proposed prototype utilizes a Selective Compliance Assembly Robot Arm (SCARA) based robot capable of cooperatively manufacturing parts. This allows …

Baseline Data From Servo Motors In A Robotic Arm For Autonomous Machine Fault Diagnosis, Jacob Brown

Mechanical Engineering Undergraduate Honors Theses

Fault diagnosis can prolong the life of machines if potential sources of failure are discovered and corrected before they occur. Supervised machine learning, or the use of training data to enable machines to discover these faults on their own, makes failure prevention much easier. The focus of this thesis is to investigate the feasibility of creating datasets of various faults at both the component and system level for a servomotor and a compatible robotic arm, such that this data can be used in machine learning algorithms for fault diagnosis. The faults induced at the component level in different servomotors include: …

Blood-Brain Barrier-On-A-Chip Systems Based On 3d Printing, Cade I. Harding

Mechanical Engineering Undergraduate Honors Theses

This research focused on the design and testing of a blood-brain barrier (BBB)-on-a-chip microfluidic device produced using 3D printing. First, COMSOL simulations were used to define dimensions of the microchannel that would most accurately replicate the flow environment imposed on the blood-brain barrier, the wall shear stress being the most important characteristic. In using COMSOL, water was used as the simulated fluid and also the testing fluid in the fabricated devices. Therefore, the microsystem is designed to produce the BBB environment using water instead of blood. The numerical simulation parameters were based on theoretical calculations performed to scale up the …

Chip-Package Interfacial Stress Analysis And Reliability Implications For Flip-Chip Power Devices, Jonathan Gh Treco

Mechanical Engineering Undergraduate Honors Theses

The solder in flip-chip assemblies experience high stress and strain because of thermal mismatch induced deformation. These deformations occur because of the differences of coefficient of thermal expansion between flip-chip assembly materials. The similarly in stress profiles between thermal induced and shear induced stress in solder joints enable the use of die shear testing as a representative technique for relating the max stress the flip-chip can withstand to cyclic thermal fatigue failures. In this work, two electronic device sample preparation types are evaluated: One set of samples are soldered together and other set of samples use epoxy as an adhesive. …

System-Layout-Dependent Thermally Induced Solder Stress & Reliability Implications, Ange C. Iradukunda

Mechanical Engineering Undergraduate Honors Theses

Electronic flip chip assemblies consist of dissimilar component materials, which exhibit different CTE. Under thermal cyclic operating conditions, this CTE mismatch produces interfacial and interconnect stresses, which are highly dependent on system layout. In this paper, sensitivity analyses are performed using ANSYS FEA to establish how the proximity and arrangement of neighboring devices affect interconnect stress. Flip chip alignment modes ranging from edge-to-edge to corner-to-corner are studied. Results of these FEA studies, demonstrated that closely packing devices together has the effect of making them act as one. This results in a significant increase in the thermomechanical stresses induced on peripheral …

Low-Cost Inkjet Process For 3-D Printing, Christopher T. Schmitt

Mechanical Engineering Undergraduate Honors Theses

This paper presents a low-cost 3-D inkjet process design. Current commercially available 3-D inkjet printers (e.g., Objet Connex) that are capable of multi-material printing are expensive and out-of-reach of most consumers. While fused deposition modeling and other extrusion-based hybrid processes for multi-material printing are becoming available, these techniques are slow and relatively low-resolution. This research attempts to fill the gap by presenting a simple and low-cost solution to bring desktop 3-D inkjet to the community by utilizing components from an Epson inkjet printer. The mechanical system was designed with maximum utilization of the Epson carriage system with the addition of …

Development Of Miniature Hybrid Rockets For Orbital Upkeep And Transfer Applications In Nano/Pico-Satellites, Derek Willingham

Mechanical Engineering Undergraduate Honors Theses

This research has developed and constructed a successful miniature hybrid rocket test assembly for research into hybrid rocket scaling issues. It is hoped that such systems will find eventual integration into small satellites. The test assembly houses 3" fuel grains and provides an inlet for gaseous oxidizer. Although far from complete, preliminary data were taken with PMMA and GOx and some useful conclusions were drawn that will benefit future research into this topic. Fuel grains with combustion chambers whose diameters range from 1/16" to 3/8" were tested at different flow rates and thrust data gathered. Maximum flow information was gathered …

Restart Capabilities Of Hybrid Rocket Motor Utilizing Gaseous Propane And Oxygen Injection System, Joseph Gracy

Mechanical Engineering Undergraduate Honors Theses

Hybrid rockets have become an increasingly popular application in professional and amateur rocketry for their outstanding performance and reliability. An issue pressing the marketability and functionality of these rockets is the ability to restart with an exclusive system after primary ignition. Research and development of a system that can be used reliably in either application to achieve restart under various conditions has been made recently using dual injection of GOX and C3H8 using a 200kV ignition system while implementing a polymethylmethacrylate (PMMA) formable polymer as primary fuel. The system used a manual valve arrangement for control. The design features most …

A Review Of Variable Valve Timing Devices, Paul Shelton

Mechanical Engineering Undergraduate Honors Theses

Variable valve timing (VVT) has evolved from simple, manual controlled engine management to automatic, electronic works of engineering. Starting from the need for more power and extending into fuel efficiency and low emissions, VVT has evolved from the constant changing of needs. This paper summarizes various devices used to control the timing of valves from the early 1920s up until 2007.