Mechanical Engineering Commons^™

Re-Evaluation Of Resistance Prediction For High-Speed Round Bilge Hull Forms, Jae Won

Theses and Dissertations

Predicting the resistance of a high-speed monohull has been of interest to Naval Architects for several decades. Even though considerable amount of research has been carried out in this area, there remains a degree of uncertainty in the accurate resistance prediction in the early design stage. This research thesis attempts to investigate a method for enhancing the accuracy of resistance prediction methods for high-speed round-bilge monohull form vessels for a wide range of volumetric Froude numbers (Fn). While a number of systematic series are in existence, their data are either not readily available or scattered in various internal reports and …

Analysis Of Bar Deformation Under Sternum Forces During Surgical Correction Of Pectus Excavatum In Children, Rohit N. Nikam

Mechanical & Aerospace Engineering Theses & Dissertations

Pectus excavatum (PE) also known as sunken or funnel chest is the most common chest wall deformity and affects 1 in every 1,000 children. In PE patients, the middle lower portion of the sternum is depressed producing concave appearance of the anterior part of the chest wall. This problem can be corrected with minimally invasive surgery developed by Dr. Donald Nuss in 1986. A specially made steel bar is implanted to lift the sternum to its normal position. This technique has been modified several times to improve safety and effectiveness of the bar placement and removal. One of the significant …

Modeling, Identification, Validation And Control Of A Hybrid Maglev Ball System, Ahmed Elhussein E. Mekky

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, the electrodynamics of a single axis hybrid electromagnetic suspension Maglev system was modeled and validated by applying it to a single axis hybrid maglev ball experiment. By exploring its linearized model, it was shown that the single axis hybrid Maglev ball has inherently unstable dynamics. Three control scenarios were explored based on the linearized model; (1) Proportional, Deferential (PD) control, (2) Proportional, Deferential, Integral (PID) and (3) PID controller with pre-filtering. This thesis has shown that a PID controller with a pre-filtering technique can stabilize such a system and provide a well-controlled response.

A parametric system identification …

The Influence Of Non-Equilibrium Pressure On Rotating Flows, Irfan Rashid Zardadkhan

Mechanical & Aerospace Engineering Theses & Dissertations

This study was undertaken to investigate the influence of pressure relaxation on steady, incompressible flows with strong streamline curvature. In the early part of this dissertation research, the significance of non-equilibrium pressure forces in controlling the structure of a steady, two dimensional axial vortex was demonstrated. In order to extend the study of pressure relaxation influences on more complex rotating flows, this dissertation has examined other rotating flow features that can be associated with hurricanes, tornadoes and dust devils. To model these flows, modified boundary layer equations were developed for a fluid column rotating near a solid plane including the …

Dynamic Model Of Sailors Descending A Navy Ship Ladder, Jonathan Coulter

Mechanical & Aerospace Engineering Theses & Dissertations

Knee moments are greater in individuals who climb Navy ship ladders than in people climbing stairs. Because it is known that people who climb stairs frequently are at greater risk for osteoarthritis and that people in the Navy report higher incidences of knee pain, it was hypothesized that the internal joint reaction forces during the sailor's descent of a ship ladder would be greater than internal joint reaction forces of gait and stair climbing. Dimensions of a commonly used Navy ship ladder were collected and a replica was constructed. The replica was instrumented to collect 3D kinematics and kinetics during …

Final Technical Report (2nd Revision) Arra: Florida Energy Code Compliance Train-The-Trainer Program, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

A multi-faceted Florida Energy Code compliance methods, tools and field verification training program was established that included development of two instructor-led and two web-based courses, instructor training and course development support, and training of building officials and contractors throughout the state.

Separate instructor-led commercial and residential 2010 Florida Energy Code compliance courses were developed for train-the-trainer class use, and existing instructor-led blueprints data collection and energy code software courses were redeveloped as web-based courses.

Through partnerships with Florida colleges, building departments and industry organizations, a total of 42 instructors were trained to provide commercial energy code compliance training and 42 …

Investigation Of Compliant Space Mechanisms With Application To The Design Of A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler

Theses and Dissertations

The purpose of this research is to investigate the use of compliant mechanisms in space applications and design, analyze, and test a compliant space mechanism. Current space mechanisms are already highly refined and it is unclear if significant improvements in performance can be made by continuing to refine current designs. Compliant mechanisms offer a promising opportunity to change the fundamental approach to achieving controlled motion in space systems and have potential for dramatic increases in mechanism performance given the constraints of the space environment. A compliant deployment hinge was selected for development after industry input was gathered. Concepts for large-displacement …

Piezoelectrically-Induced Guided Wave Propagation For Health Monitoring Of Honeycomb Sandwich Structures, Fei Song

Theses and Dissertations

Honeycomb sandwich structures have been widely used in marine and aerospace applications due to their high strength/stiffness-to-weight ratio. However, an excessive load or repeated loading in the core tends to induce debonding along the skin-core interface, threatening the integrity and safety of the whole structure. This dissertation focuses on development of guided wave strategies for health monitoring of honeycomb sandwich structures, based on a piezoelectric actuator/sensor network. The honeycomb sandwich panels, which are composed of aluminum alloy (T6061) skins and hexagonal-celled Nomex core, are specifically considered in the study. First, elastic wave propagation mechanism in honeycomb sandwich structures is numerically …

Application Of An Energy-Vorticity Turbulence Model To Fully Rough Pipe Flow, E. B. Fowler, Doug F. Hunsaker, W. F. Phillips

Mechanical and Aerospace Engineering Faculty Publications

Based on a more direct analogy between turbulent and molecular transport, a foundation was recently presented for an energy-vorticity turbulence model. The new turbulent-energytransport equation contains two closure coefficients; a viscous-dissipation coefficient and a turbulent-transport coefficient. To help evaluate the closure coefficients and provide insight into the energy-vorticity turbulence variables, fully rough pipe flow is considered. For this fully developed flow, excellent agreement with experimental data for velocity profiles and friction factors is attained over a wide range of closure coefficients, provided that a given relation between the coefficients is maintained.

Capillarity-Driven Droplet Ejection, Andrew Paul Wollman

Dissertations and Theses

Drop Towers provide brief terrestrial access to microgravity environments. When used for capillary fluidics research, a drop tower allows for unique control over an experiment's initial conditions, which enables, enhances, or otherwise improves the study of capillary phenomena at significantly larger length scales than can normally be achieved on the ground. This thesis provides a historical context for the introduction of a new, highly accessible, 2.1s tower design used for capillary research and presents a variety of demonstrative experimental results for purely capillarity-driven flows leading to bubble ingestion, sinking flows, multiphase flows, and droplet ejections. The focus of this thesis …

Human Motion Tracking For Assisting Balance Training And Control Of A Humanoid Robot, Ahmad Adli Manasrah

USF Tampa Graduate Theses and Dissertations

Abstract

This project illustrates the use of the human's ability to balance according to his center of gravity as demonstrated in two applications. The center of gravity of a human is explained in detail in order to use it in controlling the Aldebaran NAO robot and in the robot-assisted balance training.

The first application explains how a humanoid robot can mimic a human's movements via a three dimensional depth sensor where the sensor analyzes the position of a user's limbs and how the robot can lift one foot and balance on the other by redistributing the its body mass when …

Scalability Study Of Explicit Finite Element Method On Shared And Distributed Memory Architectures, Leonardo Orea-Amador, Jack F. Chessa Ph.D.

COURI Symposium Abstracts, Summer 2012

Parallel architectures in computer systems are powerful tools for processing enormous amounts of information. The results of this research will illustrate their optimal usage by evaluating the scalability of the code Abaqus in the cases of domain decomposition and loop parallelization architectures. The scalability was analyzed using concomitant variation having the DoF (Degrees of Freedom) and CPU (Central Processing Unit) numbers as the variables. Abaqus jobs with less than 100,000 DoF showed similar scalability than that of jobs with more than 500,000. These results contradict the original hypothesis which proposed that small jobs would show poor scalability and vice versa. …

Systems And Methods For Detecting Defects In Coatings Utilizing Color-Based Thermal Mismatch, Richard Alloo, Kozo Saito, Belal Gharaibeh, Keng Hoo Chuah, Nelson Kudzo Akafuah, Ahmad Salaimeh

Mechanical Engineering Faculty Patents

A method of analyzing a thermal image of a coated substrate to determine the presence of defects includes determining a defect temperature range based on a color of the coated substrate and the maximum temperature of the coated substrate in the thermal image. Thereafter, the thermal image is processed by determining a signal value of a pixel of interest based on a temperature of the pixel of interest, temperatures of pixels in a kernel of pixels surrounding the pixel of interest, and the color of the coated substrate. The signal value of the pixel of interest is then compared to …

Multi-User Methods For Fea Pre-Processing, Prasad Weerakoon

Theses and Dissertations

Collaboration in engineering product development leads to shorter product development times and better products. In product development, considerable time is spent preparing the CAD model or assembly for Finite Element Analysis (FEA). In general Computer-Aided Applications (CAx) such as FEA deter collaboration because they allow only a single user to check out and make changes to the model at a given time. Though most of these software applications come with some collaborative tools, they are limited to simple tasks such as screen sharing and instant messaging. This thesis discusses methods to convert a current commercial FEA pre-processing program into a …

High Co2 Permeation Flux Enabled By Highly Interconnected Three-Dimensional Ionic Channels In Selective Co2 Separation Membranes, Lingling Zhang, Nansheng Xu, Xue Li, Siwei Wang, Kevin Huang, William H. Harris, Wilson K. S. Chiu

Faculty Publications

Abatement of CO₂ emissions from existing fossil-fueled power plants is currently the sole near-term solution to stabilize CO₂ concentration in the atmosphere. Separation and capture of CO₂from process streams of these power plants is the first step toward this effort. In this paper, we report a high flux membrane consisting of highly and efficiently interconnected three-dimensional ionic channels prepared from a combined “co-precipitation” and “sacrificial-template” synthesis. The membranes exhibit remarkable CO₂ permeation characteristic, achieving a CO₂ flux density two orders of magnitude higher than other similar systems reported in the literature. The experimental results …

Final Report Of Task Eight: Arra Energy Code Compliance Project, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

This report summarizes the Florida energy code compliance project for both residential and commercial activities and shows results in accomplishing the Florida Energy Code compliance objectives to develop and conduct an energy code enforcement study. Work is discussed regarding efforts to find and conduct Florida Energy Code enforcement practice evaluations in residential and commercial buildings built after the March 1, 2009 code period.

Storwatts: Compressed Air Energy Storage System, Michael Biederer, John O'Malley Iii, Joseph Burke, Matthew Komo

Mechanical Engineering Senior Theses

The current problem with energy backup and grid stabilization systems is that both either require fuel and constant maintenance, such as diesel generators, or cannot perform at their peak operation and need constant replacement, like batteries. Our solution and the goal of the StorWatts senior design project was to design and create a small-scale compressed air energy storage system to be used in place of traditional energy backup and grid stabilization systems. The StorWatts system does not need fuel in order to store and generate power and therefore does not require constant refueling and maintenance. It also can work in …

Novel Platform Development Using Assembly Of Carbon Nanotube, Nanogold And Immobilized Rna Capture Element For Rapid, Selective Sensing Of Bacteria, Elizabeth I. Maurer, Kristen K. Comfort, Saber M. Hussain, John J. Schlager, Sharmila M. Mukhopadhyay

Mechanical and Materials Engineering Faculty Publications

This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleiuc acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles. The application of the compounded nano-materials for sensor development has the distinct advantage of retaining the electrical behavior …

Interfacial Friction Between Semiflexible Polymers And Crystalline Surfaces, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The results obtained from molecular dynamics simulations of the friction at an interface between polymer melts and weakly attractive crystalline surfaces are reported. We consider a coarse-grained bead-spring model of linear chains with adjustable intrinsic stiffness. The structure and relaxation dynamics of polymer chains near interfaces are quantified by the radius of gyration and decay of the time autocorrelation function of the first normal mode. We found that the friction coefficient at small slip velocities exhibits a distinct maximum which appears due to shear-induced alignment of semiflexible chain segments in contact with solid walls. At large slip velocities, the friction …

Evaluation Of Advanced Conductive Nickel Materials For Strain Sensing In Carbon Fiber Reinforced Polymers, Michael Christian Koecher

Theses and Dissertations

Due to their unique properties, carbon fiber reinforced polymers (CFRP) are becoming ever more prevalent in today's society. Unfortunately, CFRP suffer from a wide range of failure modes and structural health monitoring methods are currently insufficient to predict these failures. It is apparent that self-sensing structural health monitoring could be advantageous to protect consumers from catastrophic failure in CFRP structures. Previous research has shown that embedded nickel nanostrand nanocomposites can be used to instantaneously measure strain in carbon fiber composites, but these methods have been severely limited and can induce high stress concentrations that compromise the structural integrity of the …

Microscopic Light Field Particle Image Velocimetry, Bryce Adam Mcewen

Theses and Dissertations

This work presents the development and analysis of a system that combines the concepts of light field microscopy and particle image velocimetry (PIV) to measure three-dimensional velocities within a microvolume. Rectanglar microchannels were fabricated with dimensions on the order of 350-950 micrometers using a photolithographic process and polydimethylsiloxane (PDMS). The flow was seeded with fluorescent particles and pumped through microchannels at Reynolds numbers ranging from 0.016 to 0.028. Flow at Reynolds numbers in the range of 0.02 to 0.03 was seeded with fluorescent particles and pumped through microchannels. A light field microscope with a lateral resolution of 6.25 micrometers and …

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further …

Thermal Vacuum Integration For Cal Poly's Space Environments Laboratory, Chelsea Barackman, Steven Jackowski

Aerospace Engineering

The purpose of the senior project is to construct a thermal vacuum by utilizing a preexisting vacuum chamber in the Space Environments Lab, and a donated Advanced Thermal Sciences (ATS) chiller. While a thermal vacuum is already available on campus, building one for the Space Environments Lab would grant undergraduates access to the equipment, allowing a much better understanding of testing methods and procedures in use by the aerospace industry. This paper explains the design and analysis of the thermal vacuum (T-VAC) project as well as the operation and procedures required for the ATS chiller and fill/drain tank. The thermal …

Fabrication And Characterization Of Torsional Micro-Hinge Structures, Mike Madrid Marrujo

Master's Theses

ABSTRACT

Fabrication and Characterization of Torsional Micro-Hinge Structures

Mike Marrujo

There are many electronic devices that operate on the micrometer-scale such as Digital Micro-Mirror Devices (DMD). Micro actuators are a common type of DMD that employ a diaphragm supported by torsional hinges, which deform during actuation and are critical for the devices to have high stability and reliability. The stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. Electrostatically driven micro actuators observe to have a fully recoverable non-linear viscoelastic response. The device consists of a micro-hinge which is suspended by two …

Biaxial & Twist Testing Of Composite Carbon-Fiber Sandwich Panels For Automotive Racing Vehicles, Erik Eckberg

Materials Engineering

Composite sandwich panels were constructed with 4-ply plain weave carbon-fiber/epoxy face sheets in the 0^o/45^o/0^o/45^o orientation and 1/8^th inch Nomex honeycomb core. The panels were cut into 5-inch square test plates for mechanical testing. All testing was done on a fixture designed and fabricated by Pratt & Miller Engineering and installed on an Instron testing system at Cal Poly. The twist test was performed by supporting diagonal corners of the plate while simultaneously loading the opposite two corners at a crosshead rate of .06 in/min (ASTM 3044-94R11). Out of 10 panels tested, …

Build To Learn: Effective Strategies To Train Tomorrow’S Designers, Vimal Viswanathan, Julie Linsey

Faculty Publications, Mechanical Engineering

Build to Learn: Effective Strategies to Train Tomorrow’s Designers use various representations to externalize their ideas, physical models being an important one. Engineering students need physical models are widely used by designers and their use is promoted as an effective design tool by industry and government agencies. However, very little is known about the cognitive effects of physical models in the design process. The available guidelines are conflicting. Some researchers argue for the frequent implementation of physical models; others observe that the use of physical models fixates designers. In light of these conflicts, this research project focuses on understanding the …

Finite Element Analysis Of The Implantation Of A Self-Expanding Stent: Impact Of Lesion Calcification, Shijia Zhao, Linxia Gu, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, the deployment of a self-expanding stent in a stenosed artery was evaluated through finite element analysis. The three-layered structure of the artery and their material properties were measured and implemented in our computational models. The instant outcomes, including lumen gain, tissue prolapse, and stress distribution, were quantified, and the effect of plaque calcification was evaluated. Results showed that the peak wall stress occurred on the media layer regardless of plaque calcification. The calcified plaque mitigated the tissue prolapse and arterial wall stresses in general, compared with the soft plaque. However, the lesion calcification led to a more …

Design And Testing Of A Low Cost Prosthetic Foot, Shalan Ertis, John Kearns, Seija Maniskas

Mechanical Engineering

No abstract provided.

Pier Portal, Andrew Belis, Andrew (Andy) Crafts, Jeremy Depangher, Aaron Hein, Michael Machado, Aaron Poulos

Computer Engineering

This project constitutes the design, build, and test of a camera system that runs on a track along the length of a pier piling at the Cal Poly pier in Avila Beach. The goal of the camera system is to observe the abundant sea life active on the surface of the piling underwater and in the tidal zone. The camera system will stream live video to the internet, record HD video, and be controllable remotely. The track is mounted to the piling with brackets and extends from the sea floor to a few feet above the pier deck. The camera, …

Robotic Fingerspelling Hand For Deaf-Blind Communication, Brian Fang, Colby Dixon, Trevor Wong

Mechanical Engineering

Robotic fingerspelling hand for the deaf-blind. The hand forms the shapes of the American Manual Alphabet with 11 servos. The project was sponsored by The Smith-Kettlewell Eye Reaserch Institute.