Mechanical Engineering Commons^™

Relative Navigation Approach For Vision-Based Aerial Gps-Denied Navigation, Robert C. Leishman, Timothy Mclain, Randal W. Beard

Faculty Publications

GPS-denied aerial flight is a popular research topic. The problem is challenging and requires knowledge of complex elements from many distinct disciplines. Additionally, aerial vehicles can present challenging constraints such as stringent payload limitations and fast vehicle dynamics. In this paper we propose a new architecture to simplify some of the challenges that constrain GPS-denied aerial flight. At the core, the approach combines visual graph-SLAM with a multiplicative extended Kalman filter. More importantly, for the front end we depart from the common practice of estimating global states and instead keep the position and yaw states of the MEKF relative to …

Analysis Of An Improved Imu-Based Observer For Multirotor Helicopters, John Charles Macdonald, Robert C. Leishman, Randal W. Beard, Timothy W. Mclain

Faculty Publications

Multirotor helicopters are increasingly popular platforms in the robotics community. Making them fully autonomous requires accurate state estimation. We review an improved dynamic model for multirotor helicopters and analyze the observability properties of an estimator based on this model. The model allows better use of IMU data to facilitate accurate state estimates even when updates from a sensor measuring position become less frequent and less accurate. We demonstrate that the position update rate can be cut in half versus typical approaches while maintaining the same accuracy. We also find that velocity estimates are at least twice as accurate no matter …

Transient Small Wind Turbine Tower Structural Analysis With Coupled Rotor Dynamic Interaction, George R. Katsanis

Master's Theses

Structural dynamics is at the center of wind turbine tower design - excessive vibrations can be caused by a wide range of environmental and mechanical sources and can lead to reduced component life due to fatigue, noise, and impaired public perception of system integrity. Furthermore, periodic turbulent wind conditions can cause system resonance resulting in significantly increased structural loads. Structural vibration issues may become exacerbated in small wind applications where the analytical and experimental resources for system verification and optimization are scarce. This study combines several structural analysis techniques and packages them into a novel and integrated form that can …

A Vision-Based Relative Navigation Approach For Autonomous Multirotor Aircraft, Robert C. Leishman

Theses and Dissertations

Autonomous flight in unstructured, confined, and unknown GPS-denied environments is a challenging problem. Solutions could be tremendously beneficial for scenarios that require information about areas that are difficult to access and that present a great amount of risk. The goal of this research is to develop a new framework that enables improved solutions to this problem and to validate the approach with experiments using a hardware prototype. In Chapter 2 we examine the consequences and practical aspects of using an improved dynamic model for multirotor state estimation, using only IMU measurements. The improved model correctly explains the measurements available from …

Numerical Simulation And Optimization Of Co2 Sequestration In Saline Aquifers, Zheming Zhang

All Theses and Dissertations (ETDs)

With heightened concerns on CO2 emissions from pulverized-coal power plants, there has been major emphasis in recent years on the development of safe and economical Geological Carbon Sequestration: GCS) technology. Although among one of the most promising technologies to address the problem of anthropogenic global-warming due to CO2 emissions, the detailed mechanisms of GCS are not well-understood. As a result, there remain many uncertainties in determining the sequestration capacity of the formation/reservoir and the safety of sequestered CO2 due to leakage. These uncertainties arise due to lack of information about the detailed interior geometry of the formation and the heterogeneity …

Hydraulic And Thermal Performances Of A High Temperature Ceramic Plate-Fin Heat Exchanger (Pfhe), Vijaisri Nagarajan, Yitung Chen, Qiuwang Wang, Ting Ma

College of Engineering: Graduate Celebration Programs

• Numerical analysis was carried for novel configuration of high temperature PFHE
• Fluid flow and heat transfer properties were studied for various fin configurations
• Ripsaw fin design with thickness of 0.05 mm gives maximum heat transfer with less pressure drop and friction factor
• Validation and parametric study were carried out for all fin configurations

Numerical Characterization Of The Hydrodynamics And Thermal Behavior Of Air Flow In A "Flex-Duct" Air Distribution System, Samad Gharehdaghi, Samir Moujaes

College of Engineering: Graduate Celebration Programs

The aim of this research paper is to compute the hydrodynamic and heat transfer characteristics of the air flow inside a flexible duct used for residential/small commercial buildings. Various new information which manufacturers do not provide usually are produced numerically among which heat transfer coefficient, needed for estimating heat loss, is a principal one. Circulation zones in depressions are found to exist. It is shown that these regions act as an insulator and decrease the heat loss along the duct. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal …

Vulnerability Of Progressive Collapse In Reinforced Concrete Flat-Plate Buildings, Jinrong Liu

College of Engineering: Graduate Celebration Programs

• Progressive collapse is the spread of initial local failure, causing partial or
  even total collapse of a building.
• Flat plate structure is widely used for office and residential buildings.
• There is a large inventory of older flat plate building without continuous slab bottom reinforcement through columns.
• Limited knowledge exists regarding the risk of disproportionate collapse in
  older flat-plates under sudden column removal during abnormal events.
• Reliable mechanical model is needed for structural evaluation.

Mono-Sized Sphere Packing Algorithm Development Using Optimized Monte Carlo Technique, Karn Soontrapa, Yitung Chen

College of Engineering: Graduate Celebration Programs

In this research, fuel cell catalyst layer was developed using the optimized sphere packing algorithm. An optimization technique named adaptive random search technique (ARSET) was employed in this packing algorithm. The ARSET algorithm will generate the initial location of spheres and allow them to move in the random direction with the variable moving distance, randomly selected from the sampling range (a), based on the Lennard–Jones potential and Morse potential of the current and new configuration. The solid fraction values obtained from this developed algorithm are in the range of 0.610–0.624 while the actual processing time can significantly be reduced by …

Mimicking The Mechanical Behavior Of Advancing Disc Degeneration Through Needle Injections, Jeremy S. Alsup

Theses and Dissertations

Objective - To investigate the effects of injected protease solution on the mechanical advancement of disc degeneration, and to establish test protocol for future pre-clinical validation of spinal arthroplasty devices. The hypothesis that injection of a protease into a cadaveric lumbar disc will mimic advanced degeneration mechanics was the subject of this study. Summary of Background Information - Spinal disc degeneration is a universal condition that progresses in adults due to aging, disease, or injury. Stages of disc degeneration have been categorized in cadaver specimens, with each degeneration level exhibiting characteristic changes in flexibility parameters. Spinal disc tissue can be …

Development Of Optimization Models For The Set Behavior And Compressive Strength Of Sodium Activated Geopolymer Pastes, Brian Albert Fillenwarth

All Theses and Dissertations (ETDs)

As large countries such as China begin to industrialize and concerns about global warming continue to grow, there is an increasing need for more environmentally friendly building materials. One promising material known as a geopolymer can be used as a portland cement replacement and in this capacity emits around 67% less carbon dioxide. In addition to potentially reducing carbon emissions, geopolymers can be synthesized with many industrial waste products such as fly ash.

Although the benefits of geopolymers are substantial, there are a few difficulties with designing geopolymer mixes which have hindered widespread commercialization of the material. One such difficulty …

A Methodology For The Extraction Of Design Principles For Unfamiliar Markets, Robert D. Campbell

Theses and Dissertations

Successful product design focuses on design principles that are relevant to a target market. Consequently, the better these principles are understood and used, the higher the likelihood that resulting products will be well-received in that market. This thesis presents a method for extracting market-specific design principles for any market. The method employs user/designer-described characteristics of products within a market to extract the design principles specific to that market. The method generalizes the product characteristics, seeks to discover design decisions that could have resulted in those characteristics, and then extracts the underlying design principles. To demonstrate the ability of the method …

Efficient Multifamily Homes In A Hot-Humid Climate By Atlantic Housing Partners, Florida Solar Energy Center, Dave Chasar

FSEC Energy Research Center®

With assistance from the Florida Solar Energy Center (FSEC) and its Building America Partnership for Improved Residential Construction (BA-PIRC), Atlantic Housing Partners (AHP) has implemented a high performance, systems-engineered package of measures in the new construction multifamily housing sector in the hot-humid climate zone. This report demonstrates how the initiative achieves Building America (BA) goals of 30%-50% energy savings. In addition, the report discusses the role of utility allowance calculations, used as part of the low-income housing tax credit process, to value those energy savings.

Results of energy modeling are presented to demonstrate that the specification package achieves 40% energy …

Design And Fabrication Of An Ultra-Low Capacitive Pressure Transducer, Justin Brown, Armand Gagne, Stephen Charnley, Kyle Devlin, Ryan Finley, Jenan Almishari, Anna Wint, Dr. Shahin Nudehi

Symposium on Research and Creative Expression (SORCE)

The goal of the Capacitive Pressure Sensor project is to redesign the Alpha Instruments 168 series capacitive pressure sensor sold by Dwyer Instruments. The primary objectives of the new design will be to eliminate the use of welding in the assembly of the sensor components and to eliminate stray capacitance in the system measurements through the use of dielectric boundaries. Additionally, the sensor housing will be a stamped design in order to avoid expensive machining steps. The electrical components of the system will be tailored to accept a capacitive signal and transfer it to a voltage reading. This voltage will …

A High Energy Density All Solid-State Tungsten-Air Battery, Xuan Zhao, Xue Li, Yunhui Gong, Nansheng Xu, Kevin Gregory Romito, Kevin Huang

Faculty Publications

An all solid-state tungsten–air battery using solid oxide–ion electrolyte is demonstrated as a new chemistry for advanced energy storage. The unique design of separated energy storage from the electrodes allows for free volume expansion–contraction during electrical cycles and new metal–air chemistry to be explored conveniently.

Fully Compliant Mechanisms For Bearing Subtraction In Robotics And Space Applications, Ezekiel G. Merriam

Theses and Dissertations

Robotics and space applications represent areas where compliant mechanisms can continue to make a significant impact by reducing costs and weight while improving performance. Because of the nature of these applications, a common need is for bearing replacement mechanisms, or mechanisms that perform the function of a bearing without the complexity and failure modes associated with bearings. Static balancing is a design strategy that attempts to reduce the actuation effort of a mechanism, and has been applied to compliant mechanisms in some applications. Monolithic construction, especially by means of 3D printing technology, is a strategy whereby the mechanism links and …

A Rigorous Solution For Finite-State Inflow Throughout The Flowfield, Zhongyang Fei

All Theses and Dissertations (ETDs)

In this research, the Hseih/Duffy model is extended to all three velocity components of inflow across the rotor disk in a mathematically rigorous way so that it can be used to calculate the inflow below the rotor disk plane. This establishes a complete dynamic inflow model for the entire flow field with finite state method. The derivation is for the case of general skewed angle. The cost of the new method is that one needs to compute the co-states of the inflow equations in the upper hemisphere along with the normal states. Numerical comparisons with exact solutions for the z-component …

Influence Of Tissue Stiffness Asymmetry On Human Vocal Fold Vibration, Kimberly Stevens, Dr. Scott Thomson

Journal of Undergraduate Research

The flow-induced vibration of the human vocal folds produces the sound for voiced speech and singing. The vocal folds consist of two folds of tissue, one on each side of the larynx, that are nominally symmetric in terms of shape, composition, and stiffness. However, several voice disorders, including vocal fold scarring and inflammation, cause severe asymmetry in vocal fold tissue properties. The asymmetry can lead to irregular vocal fold vibration and subsequent decrease in voice quality. A more accurate understanding of the effect of vocal fold asymmetry can aid in the development of improved clinical care of the human voice. …

Measurement Of Wing Loads During Flapping Flight, Ryan Anderson, Dr. Mark Colton

Journal of Undergraduate Research

Ongoing research at BYU with the Flapping Flight Research Group (FFRG) is aimed at uncovering the physics behind flapping flight. Discoveries in this field could produce new aircraft designs and technolo- gies, as well as broaden our understanding of natural phenomena. One ambition of the FFRG is to quanti- fy (as determined by lift and thrust) wing trajectories followed during flight. To achieve this quantifica- tion, a precise sensor is necessary to record the lift and thrust produced during each flap.

Assessing The Impact Of The Approximations Used In The Development Of The Pulsed Laser Method For Measuring Thermal Diffusivity, Trevor Terrill, Dr. Matthew Jones

Journal of Undergraduate Research

The purpose of this project was to conduct a rigorous investigation of each of the approximations made in the development of the pulsed laser method for measuring the thermal diffusivity. Thermal conductivity is an important engineering parameter, but measuring it directly is difficult. In common engineering practice, the thermal diffusivity, specific heat, and density are measured, and the thermal conductivity is calculated from these properties. The pulsed laser or flash method is commonly employed to measure the thermal diffusivity, but it contains many restrictive approximations that are difficult to satisfy in practice. This project investigated the significance of each of …

Investigation And Development Of Of Pyrometer Coating, Weston Baxter, Dr. Dale Tree

Journal of Undergraduate Research

This project aimed to produce and test an opaque surface on an optical fiber tip that will survive temperatures up to 3000 K. The optical fiber is to be used to measure flame temperature in oxy-coal and other combustion processes.

Power Harvesting System For More Efficient, Cleaner Burning Cookstoves, Suman Pokharel, Dr. Matthew Jones

Journal of Undergraduate Research

Each day more than 2 billion people cook using open fires or fires in primitive cook stoves that are fueled with biomass (wood, straw, crop waste, dung, etc…). These fires pollute homes and the environment, leading to serious health problems and contributing to global climate change. Additionally, fuel must be purchased at relatively high prices, or many hours are required to gather sufficient fuel each day. High fuel costs add in the limited financial resources, and collecting for fuel limits time available for education or other economically productive activities.

Creation Of An Interactive Early-Stage Design Environment, Braden Hancock, Dr. Christopher Mattson

Journal of Undergraduate Research

In my proposal for an ORCA grant, I provided a plan to assist design engineers in the early stages of the design process. This I proposed to do through the development of a computational environment wherein design engineers could more fully and simply analyze the relationships between the various design objects (variables, constraints, and objectives) that define a multiobjective optimization problem (MOP). Thanks to the opportunity that I received to pursue this research, that technology has been developed and disseminated in the scientific community through two academic journals, two professional conferences, and one student conference.

Research And Design Of Transtibial Prosthetic Shower Legs, Angelina Schwartz, Dr. Eric Homer

Journal of Undergraduate Research

The aim of 2ft Prosthetics is to design, test, and distribute low-cost prostheses to below-the-knee amputees in developing countries. To do this, a research and development team focuses on the design and construction of the prosthesis. It is then tested on local amputees by the clinical trials team. During this interaction we gain many insights regarding improvements that can be made to the prosthesis to make it more comfortable, reliable, and versatile. We learned that many high- level prostheses commonly used here in the United States are not designed to be used in wet environments. Amputees must remove it to …

Noise And Vibration Reduction Of A Clothes Dryer, Daniel O'Hare

Honors Theses

As placement of washers and dryers becomes common in apartment buildings and high rises, noise generated by the dryer becomes a nuisance to the inhabitants. Whirlpool Corporation is experiencing this issue first hand with their Horizon model long vent dryers. A focus was placed on noise and vibrations caused by the dryer motor, because its vibrations are transferred throughout the structure of the dryer. The motor causing sound problems was a modified motor from the standard model, including a speed-increasing attachment in order to operate the fan at an increased speed. Through sound and vibration measurements, structural and airborne noise …

Micro Grids Fabricated For Miniature Ion Thruster, Deborah French, Jesse Taff

College of Engineering Poster Presentations

Part of the research at Boise State is a miniaturized plasma propulsion thruster. The purpose of the thruster is to provide the necessary location realignments for small satellites in space. The grid creates an electrostatic field, which extracts plasma ions from an Inductively Coupled Plasma (ICP) source. The ions are propelled toward a collector plate being a second identical grid, which in turn creates the desired thrust. The size and density of the openings in the grid are essential to optimizing the thrust produced. The grid geometry contributes to the ion departure angle (focusing) and the ion transparency. The Stainless …

Mechanical Testing And Design Of The Magnetic Linear Test Apparatus, Sam Barker, Eric Rhoads, Brittni Blessie, Zachary Harris, Courtney Hollar

College of Engineering Poster Presentations

In order to further understand the fatigue and electrical properties of multifunctional magnetic shape memory alloys (MSMA), such as nickel-manganese-gallium (Ni-Mn-Ga), it is often necessary to modify existing machinery or design unique devices. The existing linear test apparatus has accomplished the goal of straining specimens by applying linear compression in a static magnetic field. The data acquired by this apparatus has been useful, but is limited by the device’s lack of magnetic field strength variability and closed loop control, as well as its data acquisition speed. The proposed study seeks to design and test a linear test apparatus that performs …

Time-Dependent Mechanical Response Of A Composite Pfsa Membrane, Narinder S. Khattra, Zongwen Lu, Anette M. Karlsson, Michael H. Santare, F. Colin Busby, Thomas Schmiedel

Mechanical Engineering Faculty Publications

The mechanical response of a composite fuel cell membrane, made from layers of reinforced and unreinforced PFSA material, is investigated via both experimental and numerical means. First, the time-dependent mechanical properties for the reinforced layers are measured for a range of environmental and loading conditions. A three-network, viscoelastic-plastic constitutive model is developed to characterize the mechanical response of this reinforced membrane material. This constitutive model is then used in finite element simulations of a fuel cell unit (consisting of composite membrane, electrodes, gas diffusion layer and bipolar plates) where the effect of relative humidity (RH) cycling on the stress response …

Numerical Simulations And Wind Tunnel Studies Of Pollutant Dispersion In The Urban Street Canyons With Different Height Arrangements, Cheng-Hsin Chang, Jin-Shian Lin, Chii-Ming Cheng, Yung-Shan Hong

Journal of Marine Science and Technology–Taiwan

Air pollution in big city areas resulting from exhaust emissions is a major urban problem. Often traffic pollution excess controls air pollution management decisions. There are a number of elaborate predictive models of pollutant dispersion and diffusion that address the effects of variable shapes of city buildings on pollutant concentrations, but few are fully validated. This study presents ventilation behavior in different street canyon configurations. To evaluate dispersion in a model urban street canyon, a series of tests with various street canyons with different height in upwind and downwind of street canyon are presented. These buildings were arranged in 2-D …

Vibration Suppression Of Train-Induced Multiple Resonant Responses Of Two-Span Continuous Bridges Using Ve Dampers, Ying-Jie Wang, Jong-Dar Yau, Qing-Chao Wei

Journal of Marine Science and Technology–Taiwan

This paper presents a study of reducing multiple resonant peaks of high-speed trains traveling over a two-span continuous railway bridge using visco-elastic (VE) dampers. The moving train is modeled as a series of two-degree-of-freedom (2 DOF) moving oscillators with identical intervals and the two-span continuous bridge as a Bernoulli-Euler beam with uniform span. Because of closely spaced frequencies of a continuous beam, the first several frequencies of the bridge would be excited to resonance during the passage of moving trains, which may result in multiple resonant peaks appearing on the response of train-bridge system. In order to reduce the multiple …