Mechanical Engineering Commons^™

Effectiveness Of Florida's Residential Energy Code: 1979 - 2007, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

This study was commissioned by the Florida Department of Community Affairs’ Codes & Standards Section to determine the impacts of Florida’s Energy Efficiency Code over time and recommend possible changes that would increase residential efficiency. It examines each of the 14 residential energy code cycles that have occurred during the 28 year period and determines the relative change in code stringency and its impact on energy use and energy cost throughout the period. The study also examines Florida’s proposed 2007 Code1 to determine how its requirements compare with the requirements of Section 404 of the 2006 International Energy Conservation Code …

Multi-Stable Compliant Rolling-Contact Elements, Peter Andrew Halverson

Theses and Dissertations

The purpose of this research is the development of design concepts and models of large-angle, compliant, multistable, revolute joints. This research presents evidence of the capability of these models and concepts by presenting a case study in which the miniaturization of revolute joints are examined. Previous attempts at multistable revolute joints can be categorized into two categories: compliant and non-compliant mechanisms. Non-compliant multistable revolute joints are typified by a combination of pin-in-slot joints, springs, and detents. Due to factors inherit in design, noncompliant joints often succumb to friction, wear, and undesirable motion, that leads to a decline in performance. Compliant …

College Of Engineering Senior Design Competition Spring 2007, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Ultrasonic Method For Aircraft Wake Vortex Detection, Rebecca J. Rodenhiser, William W. Durgin, Hamid Johari

Office of the Provost Scholarship

This paper describes the experimental proof of concept study for an ultrasonic method of wake vortex detection. This new acoustic method uses travel time of acoustic pulses around a closed path to measure the net circulation within the acoustic path. In this application the closed path encloses the vorticity shed from one side of a Piper PA-28 aircraft wing. Magnitude and sign of circulation detected is comparable to the expected circulation generated by the Piper PA-28 test aircraft. This study demonstrates the validity of the acoustic method in detecting aircraft wake vortices. Further investigations and applications using this technique are …

An Experimental Evaluation Of Performance Variance For Internally Threaded Geometry Related To Extended Tap Wear In Low Carbon Steel, Todd E. Alberts

All-Inclusive List of Electronic Theses and Dissertations

The development of internal threads in a manufactured part is in many cases one of the final operations in the production workflow. Quality issues in thread form development can destroy a part that has previously undergone expensive machining. The issue of tap wear is one of the multi-faceted elements that have a direct correlation on the quality of threaded components. The purpose of this research centers on resultant mechanical pull performance for the stripping of internally threaded geometry in low carbon steel as measured over various increments of the tap cutting life cycle.

Autonomous And Cooperative Multi-Uav Guidance In Adversarial Environment, Ugur Zengin

Mechanical and Aerospace Engineering Dissertations - Archive

The research presented in this dissertation is aimed at developing rule-based autonomous and cooperative guidance strategies for UAVs to perform missions such as path planning, target tracking and rendezvous while reducing their risk/threat exposure level, and avoiding threats and/or obstacles by utilizing measurement information provided by sensors. First, a mathematical formulation is developed to represent the area of operation that contains various types of threats, obstacles, restricted areas, in a single framework. Once constructed, there will be no need to distinguish between adversaries as the framework already contains the information on what needs to be avoided and the level of …

Design, Analysis And Development Of A Morphable Wing Structure For Unmanned Aerial Vehicle Performance Augmentation, Abhijit Hiraman Supekar

Mechanical and Aerospace Engineering Theses - Archive

In this research, we propose mechanisms to continuously morph a wing from a lower aspect ratio to a higher and to further extremities of a gull and an inverted-gull configuration. The mechanism comprises of a linear actuator for the extension of the wing and the servo motors to obtain the gull and inverted gull configurations. The initial design and preliminary finite element representation using 3D-beams and plates in ANSYS Classic were the benchmarks to proceed for the detailed structural analysis of the complete wing in ANSYS Workbench. An elliptical pressure distribution at the quarter cord is assumed for the linear …

Design And Implementation Of A Feedback Linearizing Controller And Kalman Filter For A Magnetic Levitation System, John Andrew Henley

Mechanical and Aerospace Engineering Theses - Archive

The principal investigation undertaken in this research is the development and subsequent implementation of a feedback linearizing nonlinear controller and extended Kalman filter for a laboratory-based Magnetic Levitation (Maglev) device. The Maglev hardware is both highly nonlinear and open-loop unstable in its dynamic response. The control and estimation scheme proposed in this work is first validated using an increasingly sophisticated level of simulations. The control and estimation algorithm had the sensor noise identified using hardware data. Then, the plant noise covariance is tuned using both on-line and off-line hardware data. Additionally, the output of the nonlinear controller is then mapped …

A Generic Stability And Control Tool For Flight Vehicle Conceptual Design: Aeromech Software Development, Gary John Coleman

Mechanical and Aerospace Engineering Theses - Archive

During the conceptual design (CD) phase, various solution concepts must, and should, be explored to select the best flight vehicle size and configuration in order to meet the mission requirements. As the aerospace industry advances novel aerospace flight vehicle configurations promising larger operational performance and overall efficiency, demanding integrated flight vehicles like the flying wing configuration (FWC) or blending wing body (BWB) are under investigation. Some of these novel configurations rely on novel control effectors (CE) and complex flight control systems in order to obtain the desired performance objectives. Clearly, stability and control plays an important roll in the design …

An Evaluation Of Using Component Mode Synthesis For Structural Models, Richard Lynn Scott

Mechanical and Aerospace Engineering Theses - Archive

Structural analysts have used component mode synthesis (CMS), also known as substructuring, for decades to divide large structural models into smaller, more manageable models, and to reduce the size of the associated mathematical problem. Applying CMS can also reduce the front-end effort to build models, even models that are smaller than those for which CMS has typically been applied. This paper presents an evaluation of the accuracy of two smaller substructured models so that analysts might feel confident in applying CMS to gain the benefits. The evaluation starts with an introduction to CMS. Then, CMS is applied to a small, …

Control And Simulation Of Relative Motion For Aerial Refueling In Racetrack Maneuver, Eunyoung Kim

Mechanical and Aerospace Engineering Theses - Archive

This thesis addresses the problem of controlling the receiver aircraft to achieve a successful aerial refueling. For the performance verification of the controller, a new set of nonlinear, 6-DOF, rigid body equations of motion for the receiver aircraft has been used. The equations are written in terms of state variables that are relative to the reference frame that is attached to, translates and rotates with the tanker aircraft. Furthermore, the nonlinear equations contain the wind effect terms and their time derivatives to represent the aerodynamic coupling involved between the two aircraft. These wind terms are obtained using an averaging technique …

Probabilistic Searching Using A Small Unmanned Aerial Vehicle, Steven R. Hansen, Timothy W. Mclain, Michael A. Goodrich

Faculty Publications

Ground breaking concepts in optimal search theory were developed during World War II by the U.S. Navy. These concepts use an assumed detection model to calculate a detection probability rate and an optimal search allocation. Although this theory is useful in determining when and where search effort should be applied, it offers little guidance for the planning of search paths. This paper explains how search theory can be applied to path planning for an SUAV with a fixed CCD camera. Three search strategies are developed: greedy search, contour search, and composite search. In addition, the concepts of search efficiency and …

An Overview Of Mav Research At Brigham Young University, Timothy W. Mclain, Randal W. Beard, D. Blake Barber, Nathan B. Knoebel

Faculty Publications

This paper summarizes research efforts at Brigham Young University related to the control of miniature aerial vehicles (MAVs). Recent results in the areas of vector field path following, precision landing and target prosecution, target localization, obstacle detection and avoidance, tailsitter aircraft control, and cooperative control are presented.

A Novel Cylindrical Punch Method To Characterize Interfacial Adhesion And Residual Stress Of A Thin Polymer Film, Bing Feng Ju, Kuo Kang Liu, Ming Fung Wong, Kai Tak Wan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Adhesion of a pre-stressed silicone rubber film to a planar graphite surface was investigated by a new cylindrical punch method. a homemade apparatus was constructed to meet force and displacement resolutions of 0.1 μN and 10 nm. When the punch approached the intersurface force range across the punch-film gap, the film jumped into contact at "pull-in". Upon unloading, once the tensile load reached a threshold, a spontaneous delamination occurred at "pull-off" with a non-zero contact circle. a theoretical model was constructed based a simple energy balance. the new method can be used to characterize an adhesion interface between a pre-stressed …

Analysis Of Tapered Laminated Composite Tubes Under Tension And Torsion, Chethana Shankara Rao

Mechanical and Aerospace Engineering Theses - Archive

Closed form expressions for determining the displacement and twisting angle of tapered composite tubes are developed. The analytical expressions are developed based on the modified laminated plate theory which includes the tubular wall curvature of the laminate. It is found that the axial deformation and the twisting angle calculated by the current method agree well with the results obtained from the finite element method. The effect of stacking sequence, taper angle and fiber orientations on the axial deformation and twisting angle are studied by using the developed method. It is found that the taper angle plays a significant role on …

Factors Affecting The Spread Of A Bioterrorist Agent Through A Building, William Cantrell

Mechanical Engineering Undergraduate Honors Theses

Bioterrorism has become a concern for Americans since the 2001 anthrax letters. Many studies have been done regarding the possibilities of biological attacks since, and most deal with possibilities of large scale attacks. However, there is reason to believe that small scale attacks are more likely. Even though studies have been done revolving around the postal system and the spread of bioagents through mail, few if any studies have looked at an attack on a single building. One particular method of attacking a building would be simply releasing an aerosoled contaminant in the building. This purpose of this project is …

A Study On The Application Of Thermoelectric Heat Pumps For Heating Applications, James Lincicome

Mechanical Engineering Undergraduate Honors Theses

Typically, thermoelectric heat pumps are used in cooling applications where space and portability are important, but they can be used efficiently in heating applications under the right conditions. This paper explains the origins of the thermoelectric heat pump, its applications in society, and the technical aspects of the device. The many different appurtenances that the device requires will be discussed along with their drawbacks. The single-stage data for the cells will be compared to the two-stage configuration data, and the data gathered for a specific thermoelectric device will be compared to the manufacturer's published data for the different configurations of …

Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum

Mechanical Engineering Undergraduate Honors Theses

The Micro and Nano System Laboratory at the University of Arkansas currently is equipped with an Atomic Force Microscope (AFM). This device can be used to measure objects with resolution on the nanometer scale, but there are a number of technical difficulties in performing scans of carbon nanotubes and DNA. The goal of this research is to successfully perform scans on both carbon nanotubes and DNA and to also establish laboratory processing protocols to re-perform such scans in the future. Previous works performed by other researchers in the laboratory provided basic protocols with which to begin the present research. These …

Design Of A Supersonic Wind Tunnel, Jay Pascual

Mechanical Engineering Undergraduate Honors Theses

A supersonic wind tunnel was to be designed using the existing compressed air tank at the Mechanical Engineering building at the University of Arkansas. A throat area of 0.000375 m2 was used in the design process. The properties of the air were calculated using various Mach numbers. These results are used to determine if a wind tunnel of Mach numbers between one and five can be built at the University of Arkansas and can run for a sufficient amount of time. Also, the dimensions of the supersonic wind tunnel were calculated for these various Mach numbers.

Management Of An Intelligent Argumentation Network For A Web-Based Collaborative Engineering Design Environment, Xiaoqing Frank Liu, Man Zheng, Ganesh K. Venayagamoorthy, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Conflict resolution is one of the most challenging tasks in collaborative engineering design. In our previous research, a web-based intelligent collaborative system was developed to address this challenge based on intelligent computational argumentation. However, two important issues were not resolved in that system: priority of participants and self-conflicting arguments. In this paper, we develop two methods for incorporating priorities of participants into the computational argumentation network: 1) weighted summation and 2) re-assessment of strengths of arguments based on priority of owners of the argument using fuzzy logic inference. In addition, we develop a method for detection of self-conflicting arguments. Incorporation …

Vision-Based Landing Of Fixed-Wing Miniature Air Vehicles, Blake Barber, Timothy Mclain, Barrett Edwards

Faculty Publications

This paper outlines a method for using vision-based feedback to accurately land a MAV on a visually identifiable target of approximately known location. The method presented is robust to wind, capable of handling both stationary and moving targets, and capable of cor- recting for camera misalignment, state estimation biases, and parameter estimation biases. Landing results from actual flight tests are presented which demonstrate the effectiveness of the proposed method.

Autonomous Landing Of Miniature Aerial Vehicles, D. Blake Barber, Stephen R. Griffiths, Timothy W. Mclain, Randal W. Beard

Faculty Publications

This paper outlines an approach for automated landing of miniature aerial vehicles (MAVs). A landing algorithm defining the landing flight path as a function of height above ground, and the control strategies for following the path, are described. Two methods are presented for estimating height above ground, one based on barometric pressure measurements and the other utilizing optic-flow measurements. The development of an optic-flow sensor and associated sampling strategies are described. Utilizing estimates of height above ground from barometric pressure and optic-flow measurements, repeated landings were performed with a 1.5 m wingspan MAV. With height above ground estimated from barometric …

High Temperature Heat Exchanger Project: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Anthony Hechanova

Publications (NSTD)

• The variation of sulfur dioxide production (throughput) of the baseline design of the Ceramatec sulfuric acid decomposer with total mass flow rate of reacting flow has been calculated. According to the calculations, the sulfur dioxide production increases as the total mass flow rate of reacting flow increases regardless of the fact that decomposition percentage of sulfuric trioxide decreases. A parametric study of the baseline design of the Ceramatec sulfuric acid decomposer was performed.

• The thermal performance using various channel geometries for the decomposer was studied. The baseline design (straight channels) has 89.5% thermal efficiency while the thermal efficiency …

Closing The Gap: Getting Full Performance From Residential Central Air Conditioners, Task 4 - Develop New Climate-Sensitive Air Conditioner, Simulation Results And Cost Benefit Analysis, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

This study evaluated the impacts of conventional and advanced cooling and dehumidification equipment on residential indoor humidity levels and annual energy consumption using whole building computer simulations. The life-cycle cost premium for the various advanced systems was also estimated. Building models were developed for a standard HERS Reference house, meant to represent current residential construction practice, and a High-Efficiency house that would likely qualify for a federal tax credit. The different houses were simulated in seven southeastern U.S. cities and with two ventilation/infiltration scenarios: 1) variable or natural infiltration alone, and 2) mechanical ventilation that complied with ASHRAE Standard 62.2-2004. …

Mitigating The Impacts Of Uncontrolled Air Flow On Indoor Environmental Quality And Energy Demand In Non-Residential Buildings, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

This project builds on previous field research in Florida that has demonstrated the significant impact that uncontrolled air flows (UAFs) have on indoor environmental quality (IEQ) and energy use in small commercial buildings, a large but poorly understood segment of the nation's building stock. The goal of this project was to extend that research to a national scale by assessing the importance of UAFs in a sample of 25 commercial buildings in New York State. The differences in climate and construction techniques between New York and Florida are expected to bound the range conditions typically found on a national basis. …

Trials Bike Frame Concept, David Boboltz, Rob Harmer, Caleb Vanderveen

Honors Theses

Development of a Concept Trials Frame was a mechanical engineering design project that developed a new bicycle frame that has the strength and durability to be used for trials bike riding. The scope of the project was placed solely on the bicycle's frame. Current frames were analyzed based on their strength, durability, stiffness, weight, and appearance. These factors were ranked for importance and became the performance targets for the new frame. Several designs that utilize elastic strain energy to increase performance were brainstormed. Following SolidWorks modeling, equivalent impact loads were calculated using several analytical methods. These loads were then applied …

Coupled-Mode Theory For Stimulated Raman Scattering In High-Q/Vm Silicon Photonic Band Gap Defect Cavity Lasers, Xiaodong Yang, C. W. Wong

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We examine the dynamics of stimulated Raman scattering in designed high-Q/V_m silicon photonic band gap nanocavities through the coupled-mode theory framework towards optically-pumped silicon lasing. The interplay of other X⁽³⁾ effects such as two-photon absorption and optical Kerr, related free-carrier dynamics, thermal effects, as well as linear losses such as cavity radiation and linear material absorption are included and investigated numerically. Our results clarify the relative contributions and evolution of the mechanisms, and demonstrate the lasing and shutdown thresholds. Our studies illustrate the conditions for continuous-wave and pulsed highly-efficient Raman frequency conversion for practical realization in monolithic silicon …

Development Of A Biofidelic 'Legform' Impact Test Device, John Davis, Peter Schuster

Mechanical Engineering

Current EuroNCAP test specifications attempt to predict pedestrian lower limb injury in a lateral impact with a rigid legform test device developed by the UK's TRL (Transportation Research Lab). Research shows that the measurements taken from this device (knee bending angle, knee shear, and upper tibia acceleration) do not necessarily correspond to accurate injury prediction. Recent research suggests that the primary improvement to the current test device would be a flexible legform, or one that has more biofidelity (i.e., simulates actual human lower limb response).

The work presented in this paper first reviews current legforms developed for pedestrian impact testing, …

Panoramic Video For Efficient Ground Surveillance From Small Unmanned Air Vehicles, Joseph Aaron Jackson

Theses and Dissertations

As unmanned air vehicle (UAV) utilization increases in Wilderness Search and Rescue (WiSAR) efforts, onboard sensors yielding more information will be desired. UAVs can assist WiSAR efforts by accelerating the ground search process through returning quality aerial footage of the terrain. Additionally, tracking the progress of a search by populating a digital map with video resolution data increases confidence that a comprehensive search of the region has been made. This thesis presents methods for acquiring video from multiple video sensors and fusing them into a single rendered video stream as a Virtual Gimbal. The panoramic video stream is the first …

Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li

Journal of Marine Science and Technology–Taiwan

The stochastic chaotic motion and the threshold intensity of the external excitation force for onset of chaos of the ships in random beam waves are studied by the nonlinear stochastic dynamics theory. The random differential equation of ships’ rolling motion is established with considering the nonlinear damping, nonlinear restoring moment and the white noise wave excitation. The random Melnikov mean-square criterion is used to determine the threshold intensity for onset of chaos. The probability density function of the rolling response is calculated through solving the stochastic differential equations by applying the path integral method in the chaotic region. It is …