Mechanical Engineering Commons^™

Development Of A Data Acquisition System For Unmanned Aerial Vehicle (Uav) System Identification, Donald Joseph Lear

Mechanical & Aerospace Engineering Theses & Dissertations

Aircraft system identification techniques are developed for fixed wing Unmanned Aerial Vehicles (UAV). The use of a designed flight experiment with measured system inputs/outputs can be used to derive aircraft stability derivatives. This project set out to develop a methodology to support an experiment to model pitch damping in the longitudinal short-period mode of a UAV. A Central Composite Response Surface Design was formed using angle of attack and power levels as factors to test for the pitching moment coefficient response induced by a multistep pitching maneuver.

Selecting a high-quality data acquisition platform was critical to the success of the …

Vulnerability Assessment Of Critical Bridges In The Hampton Roads Region Of Virginia To Storm Surge Flooding Under Sea Level Rise, Luca Castrucci

Civil & Environmental Engineering Theses & Dissertations

In this thesis, a hydrodynamic model was developed to study the vulnerability of the transportation infrastructure in the Hampton Roads region of Virginia to storm surge flooding under sea level rise. The Hampton Roads region is the second most affected area by relative sea level rise in the United States. The hydrodynamic model was validated for tide prediction, and its performance in storm surge simulation was validated with data from Hurricane Irene (2011). The developed model was then applied to eight flood-prone bridges in the transportation network that connect the cities of Norfolk, Hampton, Virginia Beach, Chesapeake and Portsmouth; the …

Using Optimality Theory And Reference Points To Improve The Diversity And Convergence Of A Fuzzy-Adaptive Multi-Objective Particle Swarm Optimizer, Amit A. Kulkarni

Mechanical & Aerospace Engineering Theses & Dissertations

Particle Swarm Optimization (PSO) has received increasing attention from the evolutionary optimization research community in the last twenty years. PSO is a metaheuristic approach based on collective intelligence obtained by emulating the swarming behavior of bees. A number of multi-objective variants of the original PSO algorithm that extend its applicability to optimization problems with conflicting objectives have also been developed; these multi-objective PSO (MOPSO) algorithms demonstrate comparable performance to other state-of-the-art metaheuristics. The existence of multiple optimal solutions (Pareto-optimal set) in optimization problems with conflicting objectives is not the only challenge posed to an optimizer, as the latter needs to …

Computational Methods For Nonlinear Systems Analysis With Applications In Mathematics And Engineering, Geoffrey Kenneth Rose

Mechanical & Aerospace Engineering Theses & Dissertations

An investigation into current methods and new approaches for solving systems of nonlinear equations was performed. Nontraditional methods for implementing arc-length type solvers were developed in search of a more robust capability for solving general systems of nonlinear algebraic equations. Processes for construction of parameterized curves representing the many possible solutions to systems of equations versus finding single or point solutions were established. A procedure based on these methods was then developed to identify static equilibrium states for solutions to multi-body-dynamic systems. This methodology provided for a pictorial of the overall solution to a given system, which demonstrated the possibility …

A Low Cost Inflatable Cubesat Drag Brake Utilizing Sublimation, Adam Charles Horn

Mechanical & Aerospace Engineering Theses & Dissertations

The United Nations Inter-Agency Debris Coordination Committee has adopted a 25-year post-mission lifetime requirement for any satellite orbiting below 2000 km in order to mitigate the growing orbital debris threat. Low-cost CubeSats have become important satellite platforms with startling capabilities, but this guideline restricts them to altitudes below 600 km because they remain in orbit too long. In order to enable CubeSat deployments at higher release altitudes, a low-cost, ultra-reliable deorbit device is needed.

This thesis reports on efforts to develop a deployable and passively inflatable drag brake that can deorbit from higher orbital altitudes, thereby complying with the 25-year …

Initiating Event Analysis Of A Lithium Fluoride Thorium Reactor, Nicholas Charles Geraci

Engineering Management & Systems Engineering Theses & Dissertations

The primary purpose of this study is to perform an Initiating Event Analysis for a Lithium Fluoride Thorium Reactor (LFTR) as the first step of a Probabilistic Safety Assessment (PSA). The major objective of the research is to compile a list of key initiating events capable of resulting in failure of safety systems and release of radioactive material from the LFTR.

Due to the complex interactions between engineering design, component reliability and human reliability, probabilistic safety assessments are most useful when the scope is limited to a single reactor plant. Thus, this thesis will study the LFTR design proposed by …

The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model results is …

Investigation, Modeling And Validation Of Digital Bridge For A New Generation Hot-Wire Anemometer, Karthik Kamalakar Joshi

Mechanical & Aerospace Engineering Theses & Dissertations

The Digital Bridge Thermal Anemometer (DBTA) is a new generation anemometer that uses advanced electronics and a modified half-Wheatstone bridge configuration, specifically a sensor and a shunt resistor in series. This allows the miniaturization of the anemometer and the communication between host computer and anemometer is carried out using serial or ethernet which eliminates the noise due to the use of long cables in conventional anemometer and the digital data sent to host computer is immune to electrical noise. In the new configuration the potential drop across a shunt resistor is used to control the bridge.

This thesis is confined …

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

NASA had a goal to develop a set of modeling tools for designing next generation civil transport aircraft with reduced noise, emissions and increased fuel efficiency by 2016. To verify the models, a database of aerodynamic and acoustic data was needed for an unconventional flying wing design that was predicted to meet the goals. A Compact Jet Engine Simulator (CJES) was needed as the jet source for the 5.8% scale model. Ultra-Compact Combustor Technology from the Air Force Research Laboratory was used to reduce the conventional burner acoustic test rigs down to the required scale size. The Air Force design …

Electromagnetic Design Of A Superconducting Twin Axis Cavity, S. U. De Silva, H. Park, J. R. Delayen, F. Marhauser, A. Hutton

Physics Faculty Publications

The twin-axis cavity is a new kind of rf superconducting cavity that consists of two parallel beam pipes, which can accelerate or decelerate two spatially separated beams in the same cavity. This configuration is particularly effective for high-current beams with low-energy electrons that will be used for bunched beam cooling of high-energy protons or ions. The new cavity geometry was designed to create a uniform accelerating or decelerating fields for both beams by utilizing a TM₁₁₀ dipole mode. This paper presents the design rf optimization of a 1497 MHz twin-axis single-cell cavity, which is currently under fabrication.

Modeling Local Crabbing Dynamics In The Jleic Ion Collider Ring, Salvador Sosa Guitron, Vasiliy Morozov, Jean Delayen

Physics Faculty Publications

The Jefferson Lab Electron-Ion Collider (JLEIC) design considers a 50 mrad crossing angle at the Interaction Point. Without appropriate compensation, this could geometrically reduce the luminosity by an order of magnitude. A local crabbing scheme is implemented to avoid the luminosity loss: crab cavities are placed at both sides of the interaction region to restore a head-on collision scenario. In this contribution, we report on the implementation of a local crabbing scheme in the JLEIC ion ring. The effects of this correction scheme on the stability of proton bunches are analyzed using the particle tracking software elegant.

Trim Tuning Of Sps-Series Dqw Crab Cavity Prototypes, S. Verdú-Andrés, J. Skaritka, Q. Wu, A. Ratti, S. Baurac, C. H. Boulware, T. Grimm, J. Yancey, W. Clemens, E. A. Mcewen, H. Park

Physics Faculty Publications

The final steps in the manufacturing of a superconducting RF cavity involve careful tuning before the final welds to match the target frequency as fabrication tolerances may introduce some frequency deviations. The target frequency is chosen based on analysis of the shifts induced by remaining processing steps including acid etching and cool down. The baseline fabrication of a DQW crab cavity for the High Luminosity LHC (HL-LHC) envisages a first tuning before the cavity subassemblies are welded together. To produce a very accurate final result, subassemblies are trimmed to frequency in the last machining steps, using a clamped cavity assembly …

Wakefield Analysis Of Superconducting Rf-Dipole Cavities, Subashini De Silva, Jean Delayen

Physics Faculty Publications

RF-dipole crabbing cavities are being considered for a variety of crabbing applications. Some of the applications are the crabbing cavity systems for LHC High Luminosity Upgrade and the proposed Electron-Ion Collider for Jefferson Lab. The design requirements in the current applications require the cavities to incorporate complex damping schemes to suppress the higher order modes that may be excited by the high intensity proton or electron beams traversing through the cavities. The number of cavities required to achieve the desired high transverse voltage, and the complexity in the cavity geometries also contributes to the wakefields generated by beams. This paper …

Development Of An Analysis And Design Optimization Framework For Marine Propellers, Ashish C. Tamhane

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, a framework for the analysis and design optimization of ship propellers is developed. This framework can be utilized as an efficient synthesis tool in order to determine the main geometric characteristics of the propeller but also to provide the designer with the capability to optimize the shape of the blade sections based on their specific criteria.

A hybrid lifting-line method with lifting-surface corrections to account for the three-dimensional flow effects has been developed. The prediction of the correction factors is achieved using Artificial Neural Networks and Support Vector Regression. This approach results in increased approximation accuracy compared …

Multi-Mode Resource Constrained Project Scheduling Using Differential Evolution Algorithm, Faisal Manour Altarazi

Mechanical & Aerospace Engineering Theses & Dissertations

Project scheduling is a tool that manages the work and resources associated with delivering a project on time. Project scheduling is important to organize, keep track of the finished and in-progress tasks and manage the quality of work delivered. However, many problems arise during project scheduling. Minimizing project duration is the primary objective. Project cost is also a critical matter, but there will always be a trade off between project time and cost (Ghoddousiet et al., 2013), so scheduling activities can be challenging due to precedence activities, resources, and execution modes. Schedule reduction is heavily dependent on the availability of …

Optimal Ship Maintenance Scheduling Under Restricted Conditions And Constrained Resources, Vi Hong Nguyen

Mechanical & Aerospace Engineering Theses & Dissertations

The research presented in this dissertation addresses the application of evolution algorithms, i.e. Genetic Algorithm (GA) and Differential Evolution algorithm (DE) to scheduling problems in the presence of restricted conditions and resource limitations. This research is motivated by the scheduling of engineering design tasks in shop scheduling problems and ship maintenance scheduling problems to minimize total completion time. The thesis consists of two major parts; the first corresponds to the first appended paper and deals with the computational complexity of mixed shop scheduling problems. A modified Genetic algorithm is proposed to solve the problem. Computational experiments, conducted to evaluate its …

Biophysical Tools To Study Cellular Mechanotransduction, Ismeel Muhamed, Farhan Chowdhury, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

The cell membrane is the interface that volumetrically isolates cellular components from the cell's environment. Proteins embedded within and on the membrane have varied biological functions: reception of external biochemical signals, as membrane channels, amplification and regulation of chemical signals through secondary messenger molecules, controlled exocytosis, endocytosis, phagocytosis, organized recruitment and sequestration of cytosolic complex proteins, cell division processes, organization of the cytoskeleton and more. The membrane's bioelectrical role is enabled by the physiologically controlled release and accumulation of electrochemical potential modulating molecules across the membrane through specialized ion channels (e.g., Na^⁺, Ca²⁺, K^⁺ channels). …

Controlling The Error On Target Motion Through Real-Time Mesh Adaptation: Applications To Deep Brain Stimulation, Huu Phuoc Bui, Satyendra Tomar, Hadrien Courtecuisse, M. Audette, Stéphane Cotin, Stéphane P.A. Bordas

Computational Modeling & Simulation Engineering Faculty Publications

We present an error-controlled mesh refinement procedure for needle insertion simulation and apply it to the simulation of electrode implantation for deep brain stimulation, including brain shift.

Our approach enables to control the error in the computation of the displacement and stress fields around the needle tip and needle shaft by suitably refining the mesh, whilst maintaining a coarser mesh in other parts of the domain.

We demonstrate through academic and practical examples that our approach increases the accuracy of the displacement and stress fields around the needle without increasing the computational expense. This enables real-time simulations.

The proposed methodology …

Manual Revision Process For Project-Based Laboratory Instruction, Gene Hou, Feifei Zhong, Orlando M. Ayala

Mechanical & Aerospace Engineering Faculty Publications

A four-step laboratory manual revision process was developed in this study based upon a technical writing process for supporting project-based laboratory classes. The audience and the objectives of this type of laboratory manuals are quite different from those of traditional, descriptive laboratory classes. The project-based laboratory manual has to serve as both an operational handbook and a theoretical textbook. The proposed four-step manual revision process was implemented in the fall 2016 semester in a 3-credit, senior elective class which was built upon a commercially-rated finite element analysis software package. Student surveys and evaluations showed that the revision process greatly increased …

An Integrated Curriculum For Technical Writing In Higher Education In China, Feifei Zhong, Gene Hou

Mechanical & Aerospace Engineering Faculty Publications

This study aims to develop an effective curriculum plan to improve technical writing in higher education in China. The paper first investigated the deficiency in the curriculum design in China for English technical writing by comparing the required courses offered in Southwest Jiaotong University (SWJTU) in China with those in Old Dominion University (ODU) in US. Questionnaires and interviews were then conducted among studying abroad Chinese students, visiting scholars, English as Second Language (ESL) instructors as well as engineering professors. The collected data revealed that the oversea Chinese students were struggled more with higher order concerns in writing than lower …

Integrative Experiences Through Modeling And Simulation Of Mechatronic Systems, Mileta Tomovic, Cynthia Tomovic, Vukica M. Jovanovic, Cheng Y. Lin, Nan Yao, Petros J. Katsioloudis

Engineering Technology Faculty Publications

Learning is integrative lifelong process which requires continuous refreshing of old material and learning new material. This principle holds also for student experiences during their undergraduate studies. Students learn new material throughout their studies, and they may or may not have opportunity to use the material in different context and at different levels. As a result some of the acquired knowledge may be forgotten by the time student graduates or it may not be placed in the context of the overall program outcomes, thus material presented may not seem to have relevance to student's career. An effective method to address …

Metal Cutting And Manufacturing Economics Project For Freshmen, Hüseyin Sarper, Nebojsa I. Jaksic, Linda Vahala

Electrical & Computer Engineering Faculty Publications

This paper describes a laboratory experiment and a team project to teach manufacturing concepts to new students. This project is one of two team projects of 1.5 credit portion of a two-credit course in exploration of engineering and technology. This course teaches students skills they need late and teamwork is a major skill that they acquire. They organize into a group with specialized responsibilities for the purpose of calculating the total production time and cost of a manufactured part using turning, drilling, and milling operations. Students also learn or improve spreadsheet skills while performing data entry and necessary machining calculations. …

Sensitivity Analysis Method To Address User Disparities In The Analytic Hierarchy Process, Marie Ivanco, Gene Hou, Jennifer Michaeli

Mechanical & Aerospace Engineering Faculty Publications

Decision makers often face complex problems, which can seldom be addressed well without the use of structured analytical models. Mathematical models have been developed to streamline and facilitate decision making activities, and among these, the Analytic Hierarchy Process (AHP) constitutes one of the most utilized multi-criteria decision analysis methods. While AHP has been thoroughly researched and applied, the method still shows limitations in terms of addressing user profile disparities. A novel sensitivity analysis method based on local partial derivatives is presented here to address these limitations. This new methodology informs AHP users of which pairwise comparisons most impact the derived …

Developing A Curriculum For Marine Mechatronics Technicians, Vukica M. Jovanovic, Petros J. Katsioloudis, Ana Djuric, Mileta Tomovic, Thomas B. Stout

Engineering Technology Faculty Publications

A growing trend within the U.S. Navy is to streamline operations by deploying ships with less sailors, who are more highly skilled technicians that are trained to do a wide array of jobs. Modern ships also include various automated systems that require more highly skilled technicians for maintenance. Outdated warship designs are now being replaced with industrial grade automation equipment. Such equipment is being used in warships that encounter harsher environments than what exists in the civilian industry. Hence, there is a need for training in regards to industrial grade automation equipment for military and civilian ship repair partners. Marine …

Active Duty Training For Support Of Navy's Additive Manufacturing Strategy, Vukica M. Jovanovic, Onur Bilgen, Karina Arcaute, Michel A. Audette, Anthony W. Dean

Engineering Technology Faculty Publications

Additive manufacturing has recently gained the attention of multiple stakeholders, including those in the advanced manufacturing industry, research and government labs, academia, and the Navy community. Various efforts within the Navy focus on studying the best way for parts to be built and repaired for marine and naval vessels. Rapid manufacturing of spare components is particularly important for sailors, especially while deployed on warships, as they often do not have timely access to spare parts from the supply chain. For that purpose, a multidisciplinary team of engineering and education faculty have developed a series of workshops to train on-duty sailors …

Cryogenic Rf Test Of The First Srf Cavity Etched In An Rf Ar/Cl2 Plasma, J. Upadhyay, A. Palczewski, S. Popovic, A.-M. Valente-Feliciano, Do Im, H. L. Phillips, L. Vuskovic

Physics Faculty Publications

An apparatus and a method for etching of the inner surfaces of superconducting radio frequency (SRF) accelerator cavities are described. The apparatus is based on the reactive ion etching performed in an Ar/Cl₂ cylindrical capacitive discharge with reversed asymmetry. To test the effect of the plasma etching on the cavity rf performance, a 1497 MHz single cell SRF cavity was used. The single cell cavity was mechanically polished and buffer chemically etched and then rf tested at cryogenic temperatures to provide a baseline characterization. The cavity's inner wall was then exposed to the capacitive discharge in a mixture of …

On A Time Domain Boundary Integral Equation Formulation For Acoustic Scattering By Rigid Bodies In Uniform Mean Flow, Fang Q. Hu, Michelle E. Pizzo, Douglas M. Nark

Mathematics & Statistics Faculty Publications

It has been well-known that under the assumption of a uniform mean flow, the acoustic wave propagation equation can be formulated as a boundary integral equation. However, the constant mean flow assumption, while convenient for formulating the integral equation, does not satisfy the solid wall boundary condition wherever the body surface is not aligned with the assumed uniform flow. A customary boundary condition for rigid surfaces is that the normal acoustic velocity be zero. In this paper, a careful study of the acoustic energy conservation equation is presented that shows such a boundary condition would in fact lead to source …