Mechanical Engineering Commons^™

Analysis And Optimal Design Of Beams Using Radial Basis Function, Yung-Kang Sun

Mechanical and Aerospace Engineering Dissertations - Archive

The application of Multiquadric Radial Basis Function (MQ RBF) in the analysis and optimal design of beams are addressed in this dissertation. For static analysis, a new Least Square Collocation (LSC) method is introduced. For buckling and vibration analysis, Rayleigh-Ritz analysis procedures are presented using MQ RBF basis function. Numerical results show that LSC can provide better results than the classical collocation method when the same number of collocation points are used. In vibration analysis, MQ RBF-based Rayleigh-Ritz can be used to calculate natural frequency accurately for several hundred modes. The important question of choosing shift parameters is discussed and …

Enhancement Of Cryoinjury By Use Of Eutectic Crystallization Of An Amino Acid Adjuvant, Chuo-Li Wang

Mechanical and Aerospace Engineering Theses - Archive

Enhancement of cryoinjury by use of eutectic formation was investigated to improve the efficacy of cryosurgery. Although the enhancement of cryoinjury associated with eutectic crystallization of sodium chloride (NaCl) has been demonstrated, its advantage can be maximized with adjuvants which are biocompatible and have higher eutectic temperature than NaCl. In this study, the feasibility of glycine, which is less toxic and have higher eutectic temperature than NaCl, was tested. Two groups of MCF-7 human breast cancer cell were suspended in isotonic saline with glycine, then were frozen and thawed on a directional solidification stage in the same protocol except that …

Preliminary Modeling, Control, And Trajectory Design For Miniature Autonomous Tailsitters, Nathan B. Knoebel, Stephen R. Osborne, Deryl Snyder, Timothy W. Mclain, Randal W. Beard, Andrew Mark Eldredge

Faculty Publications

A tailsitter UAV has unique advantages over typical fixed wing aircraft or hovercraft. This paper highlights topics of interest in our preliminary research in developing a tailsitter UAV. An aerodynamic model and quaternion-based attitude and position control scheme is presented for controlling a tailsitter through hover maneuvers, with simulation results. Desired trajectories are also developed through feedback linearization of the dynamic equations, intended for quaternion-based attitude control. Finally, a hardware platform is proposed.

Selection Of Attractor Sounds For An Audio-Based Navigation System For The Visually Impaired, Brad Salisbury

Masters Theses

Research in to human hearing has been very ‘laboratory’ oriented in the sense that the test environments do not replicate most ‘real world’ situations [J.C. Middlebrooks and D.M. Green, Ann. Rev. of Psychology, 42, 135-159 (1991)]. While very useful information is gained from these types of tests, it is difficult to see how ‘real world’ situations affect sound source localization, recognition, and navigation (walking/way finding) performance. Such information is especially important to people who are visually impaired and dependent on prior knowledge of the environment or audio cues for travel. The research reported here was conducted during the development of …

Parameters Affecting Critical Heat Flux Of Nanofluids: Heater Size, Pressure Orientation And Anti-Freeze Addition, Madhav Rao Kashinath

Mechanical and Aerospace Engineering Theses - Archive

This research aims at investigating the effect, heater size, pressure, heater orientation and effect of anti-freeze addition on critical heat flux of nanofluids which have shown large potentials as coolants for high power generating uses. Nanofluids have shown about ~180 - 200% enhancement in the critical heat flux values. The effect of heater size employing three different sized heaters yielded about ~180% enhancement over pure water. The effect of pressure on critical heat flux investigated by testing nanofluids at three pressures showed ~240% increase in critical heat flux. Surface orientation effect on critical heat flux carried out for a 2 …

Development Of Three Block Thermal Compact Model And Verification Of Modified Linear Superposition Technique For Stacked Die, Suresh G. Nikalaje

Mechanical and Aerospace Engineering Theses - Archive

Over the last few years an impressive amount of progress has been achieved in the field of compact modeling of chip packages. But available compact modeling methods could not address the issue of limitation on the mesh statistics which is major concern while modeling in FEM softwares with limited number of nodes and elements. It is not possible to attain convergence of solution for thermal simulation of detailed model with the constraint on the number of nodes and elements. In this thesis, a simple and straight forward three block (3B) compact modeling method is developed. 3B compact modeling method has …

Design And Manufacturing Of Functionally Graded Materials With Polymer Chain And Nano-Reinforcement Orientation For Compressive Applications, Sanjay Varma Kalidindi

Theses and Dissertations - UTB/UTPA

Functionally Graded Materials for compressive applications were designed and manufactured by tailoring the properties of Pure Polyethylene (PE) and Vapor Grown Carbon Nanofiber (VGCNF) Reinforced PE Composites. Properties of NRPC have been extensively studied. Properties are dependent on parameters such as the reinforcement/matrix interaction; reinforcement volume fraction, orientation, dispersion, and packing, and the final matrix microstructure. However, there is limited literature on their properties under compression loading. Compression strength studies for high density PE reinforced with VGCNF for different fiber volume fraction (0%, 5%, 10% and 15%) were carried out. The role of interface and alignment was studied. Samples were …

Electrorheology Of Fullerene Suspensions, Maricela Lizcano

Theses and Dissertations - UTB/UTPA

Electrorheological fluids are suspension materials whose rheological behavior changes with an applied voltage. In particular, the material changes from a fluid to a solid behavior with an applied voltage and reverses to its original state when the voltage is removed. This function classifies ER fluids as smart materials. ER fluids may be developed and used as mechanical devices with no mechanical parts such as pumps, actuators, and dampers. Until recently, research was concentrated with micro-particle suspension fluids. This research project investigates the electrorheology of carbon nano-particle suspension.

Viscoelastic Flow In Rotating Curved Pipes, Yitung Chen, Huajun Chen, Jinsuo Zhang, Benzhao Zhang

Mechanical Engineering Faculty Research

Fully developed viscoelastic flows in rotating curved pipes with circular cross section are investigated theoretically and numerically employing the Oldroyd-B fluid model. Based on Dean’s approximation, a perturbation solution up to the secondary order is obtained. The governing equations are also solved numerically by the finite volume method. The theoretical and numerical solutions agree with each other very well. The results indicate that the rotation, as well as the curvature and elasticity, plays an important role in affecting the friction factor, the secondary flow pattern and intensity. The co-rotation enhances effects of curvature and elasticity on the secondary flow. For …

Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li

Faculty Publications

Nano-/micronecklaces with SiO₂ beads in boron strings were synthesized by simply sublimating the desired powders in a sealed quartz tube at high temperature. The boron strings have a rectangular cross section with width varying from 80to1000nm while the SiO₂ beads bear either spindle or spherical shape with a size ranging from 100nmto5μm. The spacing between the SiO₂ beads is uniform in each boron string. Both the boron strings and the SiO₂ beads are amorphous and free of defects. The supersaturated vapors of silicon and oxygen induced the SiO₂ bead formation.

Modeling And Validation Of Tension-Element Based Mechanisms For Golf Ball-Club Impact, Aaron Robison

Theses and Dissertations

Previous work has systematically and numerically demonstrated feasibility and performance benefits of the tension-element concept in golf club heads; however, higher fidelity models needed to be created and validated for this concept. There is a need for more accurate models for this concept to further investigate its performance benefits. Performance is measured in terms of impact efficiency of the ball and head and is referred to as coefficient of restitution (COR). COR is affected by the dynamic effective face stiffness and mass properties of the club. This thesis creates and validates high-fidelity, non-linear, dynamic finite element models for the tension-element …

The Energy Policy Pyramid - A Hierarchal Tool For Decision Makers, Florida Solar Energy Center, Robin Vieira

FSEC Energy Research Center®

Policies of dealing with energy programs are often misdirected. Decision makers jump first to fuel substitution to either lower emissions or counter fuel price escalation. When it comes to both return on short-term economic investment and long-term sustainability for the economy and environment, there is a clear hierarchy. This paper presents the hierarchy as The Energy Policy Pyramid©.

Cooling Performance Assessment Of Building America Homes, Florida Solar Energy Center, Dave Chasar

FSEC Energy Research Center®

Long-term monitoring of building energy use and environmental conditions has been a strong component of FSEC research since the 1980s. Fully-automated data collection, verification, archiving and management ensure accurate logging of large amounts of data simultaneously from numerous field sites prior to being made available for analysis and display via the internet. Homes are typically monitored using 15 to 50 channels of data to measure indoor and outdoor environmental conditions and energy use of heating, cooling, water heating, whole house, and other points (e.g. Solar PV or Solar DHW) if needed.

Energy performance in many Building America homes has been …

Energy Performance Aspects Of A Florida Green Roof, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

Previous green roof studies have found that planted roofs significantly reduce roof temperatures and roof heat flux, and simulations indicate cooling load reductions of up to 25%. This monitored study evaluates summer and winter energy performance aspects of a green roof on a central Florida university building addition that was completed in 2005.

Analysis of 2005 summer data indicates significantly lower peak roof surface temperatures for the green roof compared with the conventional roof and a significant shift in when the peak temperature occurs compared to the conventional roof. Summer roof heat flux estimates show the green roof to have …

Measured Crawlspace Conditions In A Hud-Code Home, Florida Solar Energy Center, David Beal

FSEC Energy Research Center®

The Florida Solar Energy Center conducted research utilizing two unconditioned, old, singlewide side-by-side manufactured homes, one with a ground cover and one with exposed dirt under it. Three different skirting options were tested, open or no skirting, perforated skirting, and solid skirting.

Ambient and crawlspace dewpoints were recorded. The data is summarized in the table below. The skirting configurations tested are in Column 1, Column 2 lists the average ambient dewpoint, 3 the ground cover crawlspace, 4 the exposed dirt crawlspace dewpoint.

Successfully sealing HUD code home crawlspaces is the last piece of the puzzle of floor failures plaguing homes …

School Conditions Will Continue To Earn Failing Grades, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This study addresses indoor air quality and general conditions problems in schools throughout the United States. Tools employed to investigate conditions include a nationwide, web-based survey, characterization of actual operating conditions in schools through field audits and diagnostic tests, and retrofits in problem schools.

Survey results found temperature to be by far the greatest comfort complaint in regular classrooms, with indoor air quality (IAQ) and then humidity being the next greatest areas of complaints. Ventilation problems were found at each of eight audited schools. These problems appear to be occurring due to a combination of factors including lack of maintenance, …

Modeling The Mechanical Effects Of Liquid Mediated Adhesion Between The Human Vocal Folds, Gifford Zach Decker

Theses and Dissertations

The vocal folds are a complex self-oscillating biological system. In the current research, an equation was developed to model viscous adhesion forces that occur when the collision of the vocal folds results in the formation of a liquid bridge. The adhesion equation was validated using experimental data, and simplified to a one-dimensional approximation with an included correction factor that adjusted the predicted pressure in situations where the one-dimensional approximation was invalid. A non-oscillating vocal fold model with a modeled liquid bridge was used to study stress resulting from viscous adhesion. The vertical normal stress magnitude ranged from about 80 to …

Contractor Variability In Construction Of Cement Treated Base Layers, Maile Anne Rogers

Theses and Dissertations

The primary purposes of this research were to identify construction factors most correlated to specific mechanical properties of cement-treated base (CTB) layers and to determine which construction factors exhibit comparatively high variability within individual construction sections of the two pavement reconstruction projects included in this study. In addition, differences between construction sections tested in this research were evaluated. The research focused on the construction of CTB layers in two pavement reconstruction projects in northern Utah, one along Interstate 84 (I-84) near Morgan and one along U.S. Highway 91 (US-91) near Richmond. The significant predictor variables associated with California bearing ratio …

Development Of An End-Effector Sensory Suite For A Rehabilitation Robot, Stephanie A. Stiber

USF Tampa Graduate Theses and Dissertations

This research presents an approach in assisting the control and operation of a rehabilitation robot manipulator to execute simple grasping tasks for persons with severe disabilities. It outlines the development of an end-effector sensory suite that includes the BarrettHand end-effector, laser range finder, and a low cost camera.

The approach taken in this research differs greatly from the currently available rehabilitation robot arms in that it requires minimal user instruction, it is easy to operate and more effective for persons severely disabled. A thorough study of the currently available systems; Manus, Raptor and Kares II arm, is also presented.

In …

Preparation Of High-Strength Nanometer Scale Twinned Coating And Foil, Xinghang Zhang, Amit Misra, Michael Nastasi, Richard G. Hoagland

Department of Mechanical and Materials Engineering: Faculty Publications

Very high strength single phase stainless steel coating has been prepared by magnetron sputtering onto a substrate. The coating has a unique microstructure of nanometer spaced twins that are parallel to each other and to the substrate surface. For cases where the coating and substrate do not bind strongly, the coating can be peeled off to provide foil.

A Solution For Commodity Field Hauling With Self-Unloading Semi-Trailers, Lee Pagens Wilkerson

Theses and Dissertations

Commodity hauling of bulk goods is a growing enterprise that has expanded from hauling agricultural products to hauling many other bulk products. Commodity trailers are used to haul agricultural products from storage facilities to processing plants. These trailers are designed for highway use but are frequently required to work in field conditions as well. In many cases this environment overstresses these trailers and results in permanent irreparable damage. In addition to the structural problems of these trailers, the current systems for unloading the bulk produce from these trailers have serious inadequacies. While functional, the currently used chain and non-chain driven …

Design Of A Linear Ultrasonic Piezoelectric Motor, Scott L. Sharp

Theses and Dissertations

A new geometrically unique ultrasonic motor (USM) was designed using finite element modeling (FEM). A USM operates by vibrating a drive tip in an elliptical motion while it is in periodic contact with a driven surface. Piezoelectric elements are used to create the elliptical motions and are driven near a resonant frequency to create the needed displacements for the motor to operate. An idea for a motor frame was conceived that consisted of an arch, a center ground, and two piezoelectric elements connected to the center ground. End caps were added between the frame and the piezoelectric elements to reduce …

A Mechanized Horseback Riding Simulator As An Aid To Physical Therapy, Jennifer Lott

USF Tampa Graduate Theses and Dissertations

Equine-assisted therapy is a nontraditional form of physical therapy that involves riding horses as a form of rehabilitation. Limited access to these riding programs justifies a need to develop a horseback riding simulator capable of simulating the gaits, bend, and collection of the horse. Research involving the development of horseback riding simulators is limited, but the available research does show promising results in the ability to aid in physical therapy.

A two-dimensional model and simulation was developed using MATLAB. Using the results from the simulation, a horseback riding simulator was designed, fabricated and tested. The physical simulator was capable of …

Droplet On A Fiber: Geometrical Shape And Contact Angle, Xiangfa Wu, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

This paper is concerned with the geometrical shape, wetting length, and contact angle of a microdroplet on a fiber by using the method free energy variation. The governing equation and relevant boundary conditions of the microdroplet were re-derived based on the free energy variation of the droplet/ fiber system. The geometrical shape of the droplet was determined as the combination of Legendre’s elliptical functions of the first and second kinds, corresponding to the previous results in literature [6]. For contact angle h >15 degree, a novel efficient semi-analytic approach was proposed to extract the contact angle from experimental data. The …

Comparison Of Sliding Mode And State-Feedback Control Applied To A Partially Treated Actively Constrained Layer Damped (Acld) Beam, Jose J. Rodriguez

Theses and Dissertations - UTB/UTPA

In this research, a sliding mode control (SMC) was utilized in the control of a partially treated, actively constrained layer damped (ACLD), Timoshenko beam model. The resulting vibration control was compared to the vibration control achieved by a state-feedback linear quadratic regulator (LQR) for several loading conditions. An observer was designed and model order reduction (MOR) was performed to achieve a simplified, efficient, and more controllable finite element system model. As a result of model simplification, modeling errors in the form of unstructured uncertainties were introduced into the system. It was determined that the SMC and LQR achieved similar vibration …

Crashworthiness Design Optimization Using Surrogate Models, Cheng-Ho Tho

Mechanical and Aerospace Engineering Dissertations - Archive

Despite the advances in computer technology, the enormous computational cost associated with the large-scale and complex nonlinear crashworthiness simulations renders it to be impractical to rely exclusively on computer simulations for crashworthiness design optimization. A preferable strategy is to employ the computational efficient surrogate model in lieu of the expensive simulations to facilitate the optimization process and design concept exploration. An added advantage of the surrogate models is that they tends to eliminate the high-frequency numerical noise which may hinder the performance of the direct gradient-based optimization technique by constructing smooth crash responses in the crashworthiness analysis. Even thought the …

Steady-Periodic Green’S Functions And Thermal- Measurement Applications In Rectangular Coordinates, Kevin . D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

Methods of thermal property measurements based on steady-periodic heating are indirect techniques, in which the thermal properties are deduced from a systematic comparison between experimental data and heat-transfer theory. In this paper heat-transfer theory is presented for a variety of two-dimensional geometries applicable to steady-periodic thermal-property techniques. The method of Green’s functions is used to systematically treat rectangles, slabs (two dimensional), and semi-infinite bodies. Several boundary conditions are treated, including convection and boundaries containing a thin, highconductivity film. The family of solutions presented here provides an opportunity for verification of numerical results by the use of distinct, but similar, geometries. …

Order And Disorder, Entropy In Math, Science, Nature And The Arts, Sol Neeman Ph.D., Arie Maharshak

Engineering Studies Faculty Publications and Creative Works

Often, science and engineering students have difficult time in viewing certain concepts in their holistic form. An example for such a concept is the concept of Entropy. Although it originated from the field of thermodynamics, the relation between order and disorder is a profound one and manifests itself in various fields, sometimes unrelated, such as math and science, nature and the arts. In the discipline of physics, the amount of disorder in a system has been quantified by the concept of Entropy. In the area of information theory it provides a quantitative measure of the amount of compression that may …

Incorporating Solid Mechanics Into Biomedical And Life Sciences, Kai-Tak Wan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Integrating and interfacing solid mechanics and life sciences is challenging, but, with effort, the two disciplines can complement one another. This paper describes work ongoing at the Mechanical and Aerospace Engineering Department of the University of Missouri at Rolla on cellular biomechanics and mechanical characterization of single cells. Also discussed is the study of tissue biomechanics in understanding the mechanical aspects of lens accommodation in human vision.

Attribute-Level Neighbor Hierarchy Construction Using Evolved Pattern-Based Knowledge Induction, Thanit Puthpongsiriporn, J. David Porter, Bopaya Bidanda, Ming En Wang, Richard E. Billo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Neighbor knowledge construction is the foundation for the development of cooperative query answering systems capable of searching for close match or approximate answers when exact match answers are not available. This paper presents a technique for developing neighbor hierarchies at the attribute level. The proposed technique is called the evolved Pattern-based Knowledge Induction (ePKI) technique and allows construction of neighbor hierarchies for nonunique attributes based upon confidences, popularities, and clustering correlations of inferential relationships among attribute values. The technique is applicable for both categorical and numerical (discrete and continuous) attribute values. Attribute value neighbor hierarchies generated by the ePKI technique …