Mechanical Engineering Commons^™

Modeling Crabbing Dynamics In An Electron-Ion Collider, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen

Physics Faculty Publications

A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) …

Integration Of Mechatronics Design Approach Into Teaching Of Modeling Practices, Vukica M. Jovanovic, Tatiana V. Goris, Ana M. Djuric, Petros J. Katsioloudis, Nathan J. Luetke, Moustafa R. Moustafa, Basim Matrood

Engineering Technology Faculty Publications

Engineering design has transformed significantly due to advances in embedded system design and computer technologies. Almost every mechanical design today has some electrical and electronic components. Many products manufactured today contain both electrical and mechanical components and systems. Mechatronics is a design process that is multi-disciplinary in nature and integrates principles of many engineering disciplines including, but not limited to, mechanical engineering and mechanical engineering technology, electrical engineering and electrical engineering technology, and controls engineering. Mechatronic systems can be found in many different places today. These range from computer hard drives and robotic assembly systems, to washing machines, coffee makers, …

Mechatronic Education At The Faculty Of Technical Sciences Novi Sad, Gordana Ostojić, Vukica Jovanović, Drazan Kozak, Zeljko Ivandić, Stevan Stankovski

Engineering Technology Faculty Publications

The emerging engineering field of mechatronics has caught the attention of many engineering professionals, academics and government officials in recent years, nationally and globally. The main reason for this is that many modern products are no longer purely electrical and electronic or mechanical. Moreover, they are integrated multidisciplinary products which are made from subsystems which require engineering knowledge of different disciplines. Hence, increasing number of universities is offering courses, certificates and programs at undergraduate and graduate levels in the area of mechatronics. This paper presents an educational program in mechatronics at the Faculty of Technical Sciences, University of Novi Sad, …

Meshless Mechanics And Point-Based Visualization Methods For Surgical Simulations, Rifat Aras

Computational Modeling & Simulation Engineering Theses & Dissertations

Computer-based modeling and simulation practices have become an integral part of the medical education field. For surgical simulation applications, realistic constitutive modeling of soft tissue is considered to be one of the most challenging aspects of the problem, because biomechanical soft-tissue models need to reflect the correct elastic response, have to be efficient in order to run at interactive simulation rates, and be able to support operations such as cuts and sutures.

Mesh-based solutions, where the connections between the individual degrees of freedom (DoF) are defined explicitly, have been the traditional choice to approach these problems. However, when the problem …

Implementation Of Analytical Fatigue Models Into Opensim To Predict The Effects Of Fatigue On Anterior Cruciate Ligament Loading, Michael A. Samann

Mechanical & Aerospace Engineering Theses & Dissertations

The anterior cruciate ligament (ACL) provides stability to the knee joint while performing activities such as a side step cut. Neuromuscular fatigue, a reduction in muscle force producing capabilities, alters lower extremity mechanics while performing a side step cut and may increase the risk of ACL injury, particularly in females. Musculoskeletal modeling allows for the measurement of muscle forces, which are difficult to measure in-vivo. Therefore, musculoskeletal modeling, may improve our understanding of the effects of neuromuscular fatigue on muscle force production and loading of the ACL. Therefore, the purpose of this study was to develop a musculoskeletal model which …

Fluid-Structure Interaction Modeling Of A F/A-18 Twin-Tail Buffet Using Non-Linear Eddy Viscosity Models, Ahmed M. Nagib M. Elmekawy

Mechanical & Aerospace Engineering Theses & Dissertations

When turbulent flow generates unsteady differential pressure over an aircraft's structure, this may generate buffeting, a random oscillation of the structure. The buffet phenomenon is observed on a wide range of fighter aircraft, especially fighters with twin-tail. More research is needed to better understand the physics behind the vortical flow over a delta wing and the subsequent tail buffet.

This dissertation reports the modeling and simulation of a steady-state one-way fluid-structure interaction for the tail buffet problem observed on a F/A-18 fighter. The time-averaged computational results are compared to available experimental data. Next, computations are extended to simulate an unsteady …

State Variable Model For Unsteady Two Dimensional Axial Vortex Flow With Pressure Relaxation, Mazin Mohammed Elbakri Abuharaz

Mechanical & Aerospace Engineering Theses & Dissertations

This research has utilized a state variable model for unsteady two dimensional axial vortex flows experiencing non-equilibrium pressure gradient forces. The model was developed successfully using perturbed radial and azimuthal momentum equations and a pressure Poisson's equations. Three main regions of the axial vortex flow were highlighted in this study including: a laminar core region, a non-equilibrium pressure envelope, and an outer potential vortex.

Linear stability theory was utilized to formulate the model and the perturbation functions were assumed to be of the Fourier type. The flow parameters considered were the Reynolds numbers, ranging between 6,000 and 14,000, and a …

System Identification Of An Autonomous Surface Vehicle, Christopher John Cook

Mechanical & Aerospace Engineering Theses & Dissertations

The modeling and system identification of a small pontoon based marine craft, without rudder control, in a controlled environment. Old Dominion University's autonomous surface vehicle was modeled using the Observer/Kalman System Identification method. The experimental position data was collected using a laser positioning system along with Arduino based sensors on board the boat to collect the motor speeds of the dual outboard motors. The data was then compiled using the System/ Observer/Controller Identification Toolbox to derive a dynamic model that is capable of providing path estimation and prediction information to the autonomous robotic system.

Static, Vibration Analysis And Sensitivity Analysis Of Stepped Beams Using Singularity Functions, Peng Cheng, Carla Davila, Gene Hou

Mechanical & Aerospace Engineering Faculty Publications

A systematic approach is presented in this paper to derive the analytical deflection function of a stepped beam using singularity functions. The discontinuities considered in this development are associated with the jumps in the flexural rigidity and the applied loads. This approach is applied to static and vibration analyses of stepped beams. The same approach is later extended to perform sensitivity analysis of stepped beams. This is done by directly differentiating the analytical deflection function with respect to any beam-related design variable. The particular design variable considered here is the location of discontinuity in flexural rigidity. Example problems are presented …

A Comparative Analysis Of Spatial Visualization Ability And Drafting Models For Industrial And Technology Education Students, Petros Katsioloudis, Vukica Jovanović, Mildred Jones

Engineering Technology Faculty Publications

The article presents the comparative study on the drafting models and spatial visualization ability of industrial and technology education students in the U.S. It discusses how the study was conducted which examined the issue based on technical drawings and with regards to the impacts of model types. The results reportedly revealed three-dimensional models are effective for promoting learning, however more studies have to be conducted.

Implementing Mechatronics Design Methodology In Mechanical Engineering Technology Senior Design Projects At The Old Dominion University, Vukica M. Jovanovic, Jennifer G. Michaeli, Otilia Popescu, Moustafa R. Moustafa, Mileta Tomovic, Alok K. Verma, Cheng Y. Lin

Engineering Technology Faculty Publications

In recent years, the nature of engineering design has changed due to advances in embedded system design and computer technologies. It is rare to engineer a purely mechanical design that does not incorporate electrical and electronic components. Mechanical engineers and mechanical engineering technologists must possess a multi-disciplinary knowledge with the understanding of both mechanical and electrical systems. For this purpose, undergraduate programs in engineering technology have added mechatronics courses to their curriculum. Mechatronics is a design process that is multi-disciplinary in nature and integrates principles of many engineering disciplines including, but not limited to, mechanical engineering, electrical engineering, and controls …

Multipacting Optimization Of A 750 Mhz Rf Dipole, A. Castilla, J. R. Delayen

Physics Faculty Publications

Crab crossing schemes have been proposed to re-instate luminosity degradation due to crossing angles at the interaction points in next generation colliders to avoid the use of sharp bending magnets and their resulting large synchrotron radiation generation, highly undesirable in the detector region. The rf dipole has been considered for a different set of applications in several machines, both rings and linear colliders. We present in this paper a study of the effects on the multipacting levels and location depending on geometrical variations on the design for a crabbing/deflecting application in a high current (3/0.5 A), high repetition (750 MHz) …

Cryogenic Testing Of High-Velocity Spoke Cavities, C. S. Hopper, Hyekyoung Park, J. R. Delayen

Physics Faculty Publications

Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

Role Of Surface Chemistry In Nanoscale Electrokinetic Transport, Secuk Atalay

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation work presents the efforts to study the electrofluidics phenomena, with a focus on surface charge properties in nanoscale systems with the potential applications in imaging, energy conversion, ultrafiltration, DNA analysis/sequencing, DNA and protein transport, drug delivery, biological/chemical agent detection and micro/nano chip sensors.

Since the ion or molecular or particle transport and also liquid confinement in nano-structures are strongly dominated by the surface charge properties, in regards of the fundamental understanding of electrofluidics at nanoscale, we have used surface charge chemistry properties based on 2-pK charging mechanism. Using this mechanism, we theoretically and analytically showed the surface charge …

Review Of Development Stages In The Conceptual Design Of An Electro Hydrostatic Actuator For Robotics, Velibor Karanović, Mitar Jocanović, Vukica Jovanović

Engineering Technology Faculty Publications

The design of modern robotic devices faces numerous requirements and limitations which are related to optimization and robustness. Consequently, these stringent requirements have caused improvements in many engineering areas and lead to development of new optimization methods which better handle new complex products designed for application in industrial robots. One of the newly developed methods used in industrial robotics is the concept of a self-contained power device, an Electro-Hydrostatic Actuator (EHA). EHA devices were designed with a central idea, to avoid the possible drawbacks which were present in other types of actuators that are currently used in robotic systems. This …

Dimensionless Criteria For Selecting Tidally-Influenced Advective-Dispersive Desalination Brine Mixing Plume Characterization Models, Alireza Shahvari

Civil & Environmental Engineering Theses & Dissertations

The very nature of requirements for implementing a desalination process is highly spatial due to the need to secure both a source for the operation and sink for brine dilution. Thus, the applicable coastal location is bound to natural tidal mixing characteristics and subjected to a near- or a far-field availability for source and sink. Mixing characteristics of coastal waters are very different from one point to another due to the spatiotemporal tidal characteristic in loco in a manner that it can vary from being highly advective to completely dispersive dominant. Once a location is identified, estimation of corresponding water …

Theory Of Constraints Project Management In A Manufacturing Environment, Shihching Kraft

Mechanical & Aerospace Engineering Theses & Dissertations

The following thesis covers the concepts of Theory of Constraints (TOC) Project Management. Introduced by Eliyahu M. Goldratt in I 984, TOC is a management philosophy that focuses on the use of critical chain project management to prioritize everyday tasks in a company. In TOC Project Management, there is always at least one resource constraint that limits the speed at which projects are completed. TOC management philosophy also recognizes that most projects in the manufacturing industry face unknown schedule delays that could cause projects to be completed late or over the planned budget. During project plan creation, plans are developed …

Micro-Scale Dielectric Spectroscopy Of Biological Cells, Arindam Ghosh

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years microfluidics has become one of the most commonly used tools to investigate cellular biology and to provide a platform for novel biomedical devices. Electrical Impedance Spectroscopy (EIS) was formulated as a non-invasive and label-fi.ee method to investigate the dielectric and the structural properties of materials. Since the early 20th century, EIS and Dielectric Spectroscopy have been applied to measure the dielectric properties of biological cells and tissues. Information about the cell membrane, cytoplasm and the nucleus can be extracted by dielectric spectroscopy. This thesis focuses on the applicability of the analytical models, in particular the Maxwell-Wagner Interfacial …

Design And Implementation Of Software For Technological Forecasting And Modeling Technological Obsolescence, Gershom Kwaku Obeng

Mechanical & Aerospace Engineering Theses & Dissertations

In a world that is highly infused with technology, it is important that an organization knows how many resources such as manpower, equipment, and funding are needed at what time so that the organization does not suffer unnecessary risks. It is also important to know when to replace equipment. After examining different methods of forecasting, it was determined that manipulation of growth curves was the best way to determine the likelihood of device failure at a specific time. An approach in engineering economics was used to estimate the cost due to the failure of various devices or groups of devices. …

Probabilistic Modeling Of Erroneous Human Response To In-Vehicle Route Guidance Systems: A Domain Decomposition-Based Algorithm, Abdullah Al Farooq

Computational Modeling & Simulation Engineering Theses & Dissertations

Drivers are generally assumed to follow the shortest route to their destinations prescribed by in-vehicle route navigation systems without mistake. However, it is not uncommon that drivers make mistakes when there are complex intersections along the route to miss turns. Such mistakes would result in following a longer route than the optimal one. In this thesis, research has been conducted to analyze the effects of the number of intersections in the shortest routes of different O-D (origin-destination) pairs. While different formulations can be employed to describe such "driving with error" model, a Domain Decomposition (DD) partitioning algorithm has been developed …

Subtalar Joint Instability: Diagnosis And Conservative Treatment, Julie Choisne

Mechanical & Aerospace Engineering Theses & Dissertations

Subtalar instability may be caused by various ligamentous injuries. Combined instability at the ankle and subtalar joint is not adequately diagnosed. Further, isolated subtalar instability is usually misdiagnosed which may lead to long term damage to the joint. Developing a non-invasive and clinically practical tool to diagnose subtalar joint instability would be an important asset. The ability of an ankle brace, a common treatment for hindfoot instability, to promote stability for the subtalar joint was not well established. The purposes of this study were to 1) assess the kinematics of the subtalar, ankle, and hindfoot in the presence of isolated …

Field Emission Studies Toward Improving The Performance Of Dc High Voltage Photoelectron Guns, Mahzad Bastaninejad

Mechanical & Aerospace Engineering Theses & Dissertations

Field emission is the main mechanism that prevents DC high voltage photoemission electron guns from operating at the very high bias voltages required to produce low emittance beams. Gas conditioning is shown to eliminate field emission from cathode electrodes used inside DC high voltage photoelectron guns. Measurements and simulation results indicate that gas conditioning eliminates field emission from cathode electrodes via two mechanisms: sputtering and implantation, with the benefits of implantation reversed by heating the electrode. The field emission characteristics of 5 stainless steel electrodes varied significantly upon the initial application of voltage but improved to nearly the same level …

Preliminary Development Of A Subject Specific Finite Element Model Of The Hindfoot, Liang Dong

Mechanical & Aerospace Engineering Theses & Dissertations

The human hindfoot is a complex structure and its medical treatment can vary from patient to patient. If physicians have access to a patient specific computer model, the optimal treatment option can be explored on the model before preforming it on the patient. The purpose of this study was to create a quasi-static finite element model and to show the stress contour in the cartilage between the bones. Ankle joint contact pressure was collected on one cadaver limb with a 40 lbs ( 178 N) axial load applied and tendon loads applied to simulate the ratio of tendon loading during …

Static And Vibration Analyses, And Sensitivity Analysis Of Stepped Beams Using Singularity Functions, Carla Rocio Davila

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis intends to prove that singularity functions can be used to perform static and vibration analyses and their sensitivity analysis of stepped beams subjected to various support constraints. Specifically, this thesis develops formulations using singularity functions for static and vibration analyses of a simply-supported, a roller­ supported, and a spring-supported stepped beam. The Static and Vibration Sensitivity Analysis formulations are derived for the simply-supported beam to show the feasibility of this approach. The techniques presented in this thesis can be extended to various other supports constraints such as a middle support, and spring support or any other variation of …

Development And Assessment Of An In-Situ Load System, Kenneth Toro

Mechanical & Aerospace Engineering Theses & Dissertations

The In-situ Load System (ILS) was designed at NASA Langley Research Center (LaRC) to perform multi-component check loads on a force balance at a test facility. The ILS is designed to allow a force balance to be placed at off nominal orientations, while maintaining an applied load in the gravitational direction. This allows for multicomponent loads to be applied to a balance as a function of balance orientation and ILS configuration. The system is designed to be used in conjunction with a facilities existing pitch and roll control systems.

The ILS was modified to provide higher load ranges than those …

Multi-Objective Preliminary Design Optimization Of Planing Craft Using Differential Evolution And Artificial Networks, Robert Eugene Weidman

Mechanical & Aerospace Engineering Theses & Dissertations

The differential evolution (DE) algorithm is an evolutionary algorithm that has been utilized as a metaheuristic optimizer in the last few years. A recently developed multi-objective version of DE is utilized in this research in order to optimize the preliminary design of planing craft. The craft performance is evaluated using the planing hull preliminary design software PHAST. The optimization problem objectives are the craft acquisition cost and the overall measure of effectiveness; the latter comprises various performance aspects: ride quality, transportability, payload, and mobility. Static stability and operating constraints are also considered. Each of the aforementioned four measures of effectiveness …

Computational Dynamics For The Flexible Multi-Body System, Yu Liu

Mechanical & Aerospace Engineering Theses & Dissertations

Research in computational dynamics has tremendously developed in the recent years because of the demand for analysis and simulation of various multi-body systems in the growing bio-medical, mechanical and aerospace industries. These multi-body systems are made of individual bodies that are interconnected via mechanical joints. Mathematically, these joints that connect the bodies can be described as constraint equations imposed upon the motions of the involved free bodies. This process will result in an equation of motion expressed in the form of a differential-algebraic equation (DAE). This is one of the main difficulties when dealing with the multi-body system because these …

Distal Placement Of An End-To-Side Bypass Graft Anastomosis: A 3d Computational Study, John Di Cicco, Ayodeji Demuren

Mechanical & Aerospace Engineering Faculty Publications

A three-dimensional (3D) computational fluid dynamics study of shear rates around distal end-to-side anastomoses has been conducted. Three 51% and three 75% cross-sectional area-reduced 6 mm cylinders were modeled each with a bypass cylinder attached at a 30-degree angle at different placements distal to the constriction. Steady, incompressible, Newtonian blood flow was assumed, and the full Reynolds-averaged Navier-Stokes equations, turbulent kinetic energy, and specific dissipation rate equations were solved on a locally structured multiblock mesh with hexahedral elements. Consequently, distal placement of an end-to-side bypass graft anastomosis was found to have an influence on the shear rate magnitudes. For the …

A Polymer-Based Microfluidic Device With Electrolyte-Enabled Distributed Transducers (Eedt) For Distributed Load Detection, Peng Cheng

Mechanical & Aerospace Engineering Theses & Dissertations

The capability of detecting distributed static and dynamic loads is indispensable in a wide variety of applications, such as examining anatomical structures of biological tissues in tissue health analysis and minimally invasive surgery (MIS) and determining the texture of an object in robotics. This dissertation presents a comprehensive study of a polymer-based microfluidic device with electrolyte-enabled distributed transducers and demonstrates a new concept on using a single microfluidic device for distributed-load detection, which takes advantage of the low-cost microfluidic fabrication technology and the low modulus and biocompatibility of polymer. The core of the device is a single deformable polymer microstructure …

Kinematic And Dynamic Collision Statistics Of Cloud Droplets From High-Resolution Simulations, Bogdan Rosa, Hossein Parishani, Orlando Ayala, Wojciech W. Grabowski, Lian-Ping Wang

Engineering Technology Faculty Publications

We study the dynamic and kinematic collision statistics of cloud droplets for a range of flow Taylor microscale Reynolds numbers (up to 500), using a highly scalable hybrid direct numerical simulation approach. Accurate results of radial relative velocity (RRV) and radial distribution function (RDF) at contact have been obtained by taking advantage of their power-law scaling at short separation distances. Three specific but inter-related questions have been addressed in a systematic manner for geometric collisions of same-size droplets (of radius from 10 to 60 μm) in a typical cloud turbulence (dissipation rate at 400 cm² s^-3. Firstly, …