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Mechanical and Aerospace Engineering Theses - Archive

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Full-Text Articles in Mechanical Engineering

Mean Pressure Measurements Of Micro-Vortex Generator At Mach 2.5, Yusi Shih Jan 2010

Mean Pressure Measurements Of Micro-Vortex Generator At Mach 2.5, Yusi Shih

Mechanical and Aerospace Engineering Theses - Archive

Shock wave/boundary layer interactions (SBLIs) are always an important issue for high-speed vehicles. SBLIs reduce the performance of aerodynamic surfaces and engine inlets, amongst a number of adverse effects. Micro-vortex generators (MVGs) are a potential flow control method that has seen intense investigation recently and have even been implemented in actual configurations at low speeds. The present research is focused on the mean pressures at Mach 2.5 around an MVG. Experiments were performed with a baseline flat plate and also with two MVG configurations (70 and 45 trailing edge) mounted ahead of a 5° ramp. In the present study MVGs …


Axial Wave Propagation In Truncated Cones, Bhumil A. Diwanji Jan 2010

Axial Wave Propagation In Truncated Cones, Bhumil A. Diwanji

Mechanical and Aerospace Engineering Theses - Archive

While dealing with problems of impact analysis, where the force is dependent on the time, one can use the transient analysis to compute the response. Transient wave propagation has drawn interest from a long time mainly because of the way structural members behave when subjected to high rates of loading. Solutions to these problems find applications in the design of various mechanical equipments, or any situation where rigid objects are impacting on structural members.The first part of this study deals with the axial wave propagation in cones of different apex angles using transient analysis in ANSYS. The results from the …


Fiber-Optic Pressure Sensor For Time-Of-Flight Measurements In A Shock Wave, Karthikeyan Jagadevan Jan 2010

Fiber-Optic Pressure Sensor For Time-Of-Flight Measurements In A Shock Wave, Karthikeyan Jagadevan

Mechanical and Aerospace Engineering Theses - Archive

Fiber-optic sensors are widely employed to detect pressures and temperatures precisely. In particular, MEMS-based Ber-optic sensors are immune to electromagnetic interference but may have limitations at high temperatures as encountered in combustors. To ensure high-temperature survivability, such sensors may be bondedanodically. This project explains the development of a Ber-optic pressure sensor utilizing intensity based principle whereby a fused silica optical window was glued to the tungsten carbide enclosure. The development was estimated to determine high pressures of up to at least 3.5 MPa (507 psi). The sensor is designed to capture the pressure pulse and the time-of-flight (TOF) of a …


Peak Stress Of Composite Multiple-Hole Laminates With And Without Patch, Sakthivel Selvaraj Jan 2010

Peak Stress Of Composite Multiple-Hole Laminates With And Without Patch, Sakthivel Selvaraj

Mechanical and Aerospace Engineering Theses - Archive

In repairing of composite structures, the damage in the composite laminate is usually removed in the form of circular cutouts which results in holes in the laminate. Then a patch laminate is adhesively bonded to the damaged composite laminate. The presence of holes in any structures creates a high stress concentration at the edge of the hole which indeed reduces the life of the structure. The primary objective of this study is to investigate the high stress of the damaged laminate with different hole patterns and the effect of having single and double patches with various configurations on these hole …


Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad Jan 2010

Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad

Mechanical and Aerospace Engineering Theses - Archive

This study presents a 1-dimensional mathematical model of steam reformer to be used with high temperature solid oxide fuel cell (SOFC). Steam reforming (SR) is widely used in industries to produce hydrogen from hydrocarbons. There are various physical processes associated with chemical reactions in the SR of methane such as mass, heat and momentum transport. In this study a one-dimensional SR reactor with built-in preheater and mixing chamber connected to fuel gas and steam reservoirs is modeled and analyzed. The main part of the reformer is a metallic tube with catalyst coating on the inner walls, and it can be …


Alternative Cooling Technologies For Telecommunication Data Centers: Air Cooling And Rear Door Heat Exchangers, Venkata Naga Poornima Mynampati Jan 2010

Alternative Cooling Technologies For Telecommunication Data Centers: Air Cooling And Rear Door Heat Exchangers, Venkata Naga Poornima Mynampati

Mechanical and Aerospace Engineering Theses - Archive

Telecommunication industry is currently emphasizing to a miniaturization and convergence. The need for smaller, smarter and faster devices is leading drastic increment in power density and accordingly, thermal management of such devices has become a challenge. The heat generated by the devices has to be dissipated in order to ensure proper and efficient functioning of the electronics. Electronics cooling ranges from device level to the room level cooling. Data Center is a facility (room) consisting of servers used for managing and transferring data or information. The thermal management of this facility is challenging due to the huge decrease in floor …


Development Of An Optical Fiber-Based Corrosion Detection Sensor Based On Laser Light Reflection, Manjunatha Shenoy Jan 2010

Development Of An Optical Fiber-Based Corrosion Detection Sensor Based On Laser Light Reflection, Manjunatha Shenoy

Mechanical and Aerospace Engineering Theses - Archive

Corrosion plays a detrimental effect on the structural integrity of many engineering structures. It can compromise the safe operation of these structures by forming corrosion pits that deteriorates the structural surfaces and causes stress concentrations. Therefore, it is critical that corrosions are detected before structural integrity is compromised and repair becomes economically prohibitive. However, corrosions usually occur at intricate places that are hard to inspect visually. Manual inspection of the structures for corrosions requires dismantling the structures, which incurs high maintenance costs and could potentially cause damage to the components. One approach to reduce this cost is to detect and …


An Integration Of A Modern Flight Control System Design Technique Into A Conceptual Design Stability And Controls Tool, Aeromech, Amen Omoragbon Jan 2010

An Integration Of A Modern Flight Control System Design Technique Into A Conceptual Design Stability And Controls Tool, Aeromech, Amen Omoragbon

Mechanical and Aerospace Engineering Theses - Archive

The aircraft conceptual design (CD) phase is the most abstract, thus challenging phase of the entire aircraft design process. It is the responsibility of the CD engineer to identify and then to explore various aircraft concepts with the goal of arriving at the most promising concept for further evaluation. During this early design phase, the discipline stability and control tends to be underrepresented due to the lack of non-linear aerodynamic and inertia data. The methodology and software AeroMech is a vehicle configuration independent aircraft conceptual design stability and control tool, developed to help the conceptual designer to address stability and …


Imbalance Response Of A Four Degree Of Freedom Rigid Rotor Supported By Hybrid Three Pad Air Foil Bearing, Prajwal Krishna Shetty Jan 2010

Imbalance Response Of A Four Degree Of Freedom Rigid Rotor Supported By Hybrid Three Pad Air Foil Bearing, Prajwal Krishna Shetty

Mechanical and Aerospace Engineering Theses - Archive

Air foil bearings (AFB's) are widely used in small to midsized turbomachinery. They provide safer, cleaner and cheaper bearing operation. They are simple in construction, offer very low drag friction and have very high reliability at high speed operations. A major advantage of air foil bearings compared to conventional rigid surface bearings is their superior dynamic performance in rotor bearing systems. Since there is no contact between the rotor and bearing surface, the air foil bearings have a higher service life compared to rigid surface bearings. Hybrid AFB's operate under both hydrodynamic and hydrostatic condition. The present study is a …


Cae Tools For Modeling Inertia And Aerodynamic Properties Of An R/C Airplane, Kartik Kiran Parikh Jan 2009

Cae Tools For Modeling Inertia And Aerodynamic Properties Of An R/C Airplane, Kartik Kiran Parikh

Mechanical and Aerospace Engineering Theses - Archive

Recently there has been significant research in the field of Unmanned Aerial Vehicles (UAV). For efficient deployment and operation of these vehicles, it is imperative that one understands the physical system. This in turn involves one to design efficient control algorithms for implementation in these platforms. Thus we need algorithms and methods that identify the physical system parameters, that in turn can be used to design robust model based control systems. This thesis employs CAE software such as SolidWorks, GAMBIT and FLUENT to calculate the aerodynamic coefficients and moment of inertia. The aerodynamic coefficients are analyzed to understand the sensitivity …


Fabrication Of Plga Nanocomposite Using Two Photon Polymerization, Nikhil Narendra Kavadia Jan 2009

Fabrication Of Plga Nanocomposite Using Two Photon Polymerization, Nikhil Narendra Kavadia

Mechanical and Aerospace Engineering Theses - Archive

The demand of smaller size 3D structures in scale of several nanometers has significantly increased the need of development of new techniques for micro/nano fabrication. Applications of nanomaterial embedded true 3D micro/nano structures in the field of medicine, tissue engineering, scaffolding, drug delivery, antibacterial implants or catheters, modification of textiles and refinement of polymers has opened new areas of research for fabrication of nanocomposites embedded with engineering nanoparticles.A novel fabrication process called two photon polymerization (2PP) is employed for the fabrication of polymeric nanocomposites embedded with PLGA nanoparticles. An ultra short pulsed laser source is used to produce laser at …


Dymore Finite Element Analysis Of The Paired Blade Tiltrotor Conceptual Design And A Comparable Conventional Tiltrotor Design, David Orion Braziel Jan 2009

Dymore Finite Element Analysis Of The Paired Blade Tiltrotor Conceptual Design And A Comparable Conventional Tiltrotor Design, David Orion Braziel

Mechanical and Aerospace Engineering Theses - Archive

Increasing the solidity of tiltrotors above that of current designs presents challenges associated with control system packaging and control couplings. The paired blade rotor concept addresses these issues by placing two blades that share a pitch link, located for acceptable control coupling, on each of three hub arms.Dymore finite element models of the paired blade rotor and a reference rotor of equal solidity with six evenly spaced blades were developed to identify any potential design flaws of the paired blade rotor associated with rotor frequency placement or control couplings. The finite element rotor models are documented, and the results of …


Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah Jan 2009

Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah

Mechanical and Aerospace Engineering Theses - Archive

Multifunctional nanoparticles hold considerable promise as the next generation of medicine that allow for detection of early on-set of diseases and targeted therapy with minimal toxicity. To achieve targeted drug delivery, nanoparticles are usually functionalized with certain ligands (polymers) that bind specifically to a particular type of receptors on the endothelial cell surface, which are expressed exclusively during its diseased state. The ligand coated nanoparticles, loaded with drugs inside, transport in blood stream, and adhere to diseased cells via specific adhesion. However, this whole procedure becomes complicated due to simultaneous involvement of hydrodynamic force, adhesion force and Brownian force. In …


Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard Jan 2009

Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard

Mechanical and Aerospace Engineering Theses - Archive

Accurate prediction of stress from impact would be very useful to an engineer in the design and analysis phases of a project. Currently one must resort to finite element analysis and experimentation, both of which have their negatives. Classical hand analysis methods such as the work-energy method overestimate the stress for a weight dropped onto the tip of a cantilevered beam. The goal of this project was to formulate analytical equations that were straightforward and easy to implement that would more accurately predict the dynamic stress in this scenario. Using the already derived equations from the work-energy method, a modification …


Improving Receiver Station-Keeping In Aerial Refueling By Formulating Tanker Motion As Disturbance, Christopher Michael Elliott Jan 2009

Improving Receiver Station-Keeping In Aerial Refueling By Formulating Tanker Motion As Disturbance, Christopher Michael Elliott

Mechanical and Aerospace Engineering Theses - Archive

During aerial refueling operations, the receiver aircraft should hold position within a “refueling box” to maintain the boom-receptacle connection while the tanker aircraft flies in a racetrack maneuver. Prior research work shows, especially in turns, significant difficulty resides in meeting y-deviation requirements, i.e., to stay within the box in the lateral direction. This observation indicates tanker motion as “the biggest disturbance” in turn. The nonlinear equations of motion for the receiver aircraft used in this work are developed in terms of position and orientation states relative to the tanker. Linearization results in a set of equations with tanker motion clearly …


On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala Jan 2009

On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala

Mechanical and Aerospace Engineering Theses - Archive

The current state of the art in coronary stent technology is mainly populated by metallic stents usually coated with certain drugs to increase biocompatibility, even though experimental biodegradable stents have appeared in the horizon. To design stents from biodegradable polymers one must accurately characterize their mechanical behavior for analysis and optimization.This manuscript presents the process for evaluating the material properties for biodegradable biocompatible POC-HA polymeric composite, techniques for developing the stent models for finite element analysis, and development of material models for finite element analysis. The developed material models were utilized in finite element analysis to evaluate the suitability of …


Finite Element Analysis Of Forging, Aditya Ashok Battin Jan 2009

Finite Element Analysis Of Forging, Aditya Ashok Battin

Mechanical and Aerospace Engineering Theses - Archive

Numerical modeling and simulation of metal forming is very effective in saving production time, effort and economy and has thus gained prominence in many industries all over the world. In metal-forming finite element analysis, software like Deform, Qform, Forge, Simufact, Hyperform are used extensively for the forming analysis. Apart from having narrow applications, these softwares are expensive. The object of this study was to examine the robustness of general package softwares in regards to forging. Software such as Abaqus and Ansys LSDyna were used to simulate the forging process. The case examined was that of a circular metal disc restrained …


Multi Objective Optimization Of Graphite Heat Spreader For Portable Systems Application, Arijit Banerjee Jan 2009

Multi Objective Optimization Of Graphite Heat Spreader For Portable Systems Application, Arijit Banerjee

Mechanical and Aerospace Engineering Theses - Archive

The advancement made in portable electronic systems has primarily been due to miniaturization of electronic systems. This in turn leads to an increase in power density which leads to higher temperatures and formation of hot spots. There is a temperature specification of system surfaces for human comfort (such as the surface close to a keyboard on laptops). Challenge in cooling portable devices is that there is not enough room to accommodate heat sinks. It is therefore important to have heat spreaders that can transfer the heat from critical devices to regions where cooling is available. Traditionally, copper has been the …


A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally Jan 2009

A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally

Mechanical and Aerospace Engineering Theses - Archive

The study of bubble formation from an orifice finds numerous industrial applications which include bubble acoustics in ocean physics and chemical reactors. Numerical simulations have been performed to investigate the dynamics of bubble formation, growth and detachment from an orifice. The full transient Navier - Stokes equation is solved in a two-dimensional axi-symmetrical coordinate system. The surface tension implementation algorithm known as the Pressure Boundary Method (PBM) is used to model the surface tension. The robustness of PBM method on Two-Phase flows with different conditions has been shown. The results achieved by numerical simulations have been compared with the available …


Heat Transfer Analysis Of A Pulse Detonation Engine, Neelima Kalidindi Jan 2009

Heat Transfer Analysis Of A Pulse Detonation Engine, Neelima Kalidindi

Mechanical and Aerospace Engineering Theses - Archive

A thermal analysis of the effect of sensible heat release on the walls of the detonation chamber for stoichiometric mixtures of hydrogen/air, octane/air and octane/oxygen was presented. The detonation tube was assumed to operate at 20 Hz and cooled by a water jacket to dissipate the heat from the walls which ensures the effective operation for a longer period. Wall material was assumed to be made of copper because of its high thermal conductivity.The study showed a slow temperature rise along the walls of the combustion chamber for multiple pulses. It can be concluded that due to the space-time averaging …


Thermal Conduction Equations For A Medium With An Inclusion Using Galerkin Method, Thiagarajan Sivalingam Jan 2009

Thermal Conduction Equations For A Medium With An Inclusion Using Galerkin Method, Thiagarajan Sivalingam

Mechanical and Aerospace Engineering Theses - Archive

The Galerkin method is used to semi-analytically solve the heat conduction equation in non-homogeneous materials. The problem under deliberation is a square plate with a circular inclusion having different thermal conductivities. A generalized procedure that involves the Galerkin method and formulation of the final solution in terms of the procured base functions is adopted. The Galerkin method basically involves expressing the given boundary value problem in terms of a standard mathematical relation, generating a set of continuous base functions, formulating the matrix equation, and determining the solution.For the non-homogeneous material, a set of base functions for the plate and inclusion …


Structural Optimization Using Ansys Classic And Radial Basis Function Based Response Surface Models, Vijay Krishna Jan 2009

Structural Optimization Using Ansys Classic And Radial Basis Function Based Response Surface Models, Vijay Krishna

Mechanical and Aerospace Engineering Theses - Archive

This thesis describes a methodology to develop an effective and simple structural optimization method using Response Surfaces. It also further demonstrates how these Response Surfaces can then be utilized for further Multi Objective Optimization. The true or exact responses were calculated using Ansys Classic while the codes for the training and simulation of Response Surface is pro-grammed in Matlab. Initially we used a Halton sequence to generate a DOE of the design variables. Then we used Ansys Classic to generate the exact responses. Once the responses were imported the Response Surface are generated using a RBF approximation model. This RBF …


Electrowetting On Dielectric (Ewod) Digital Microfluidics For Electronic Hotspot Cooling, Govindraj Shreyas Bindiganavale Jan 2009

Electrowetting On Dielectric (Ewod) Digital Microfluidics For Electronic Hotspot Cooling, Govindraj Shreyas Bindiganavale

Mechanical and Aerospace Engineering Theses - Archive

Electronics cooling was a field dominated by bulky and heavy heat sinks, heat pipes and fans for decades. Lately, the size of the electronic components has decreased to a substantial extent with an increase in performance. This has fuelled a need for smaller, lighter, yet efficient cooling systems. A lot of research has been done to build innovative cooling solutions which satisfied most of the requirements as stated above. Some of them still have limitations like use of the right coolants and design challenges. Digital microfluidics is one field which can solve all these issues by providing a simple, reliable …


A Generic Methodology For Flight Test And Safety Evaluation At Conceptual Design, Amit R. Oza Jan 2009

A Generic Methodology For Flight Test And Safety Evaluation At Conceptual Design, Amit R. Oza

Mechanical and Aerospace Engineering Theses - Archive

The current research is dedicated to the application of a simulation suite that emulates flight testing and is applicable to the aircraft conceptual and preliminary design environment. The configuration concept available for study is an unmodified Cessna Citation X. The research goal is to arrive at a systematic process that reduces aircraft design risk while creating transparency for the manager and engineer during product life-cycle simulation. When integrating the discipline of flight test emulation into the development methodology, the objective is to complement and enrich the design simulation through a correct representation of flight safety relevant disciplines like aircraft certification, …


High Temperature Microporous Coatings: The Effects Of Wetting And Wicking On Nucleate Boiling And Chf, Ross Evan Pivovar Jan 2009

High Temperature Microporous Coatings: The Effects Of Wetting And Wicking On Nucleate Boiling And Chf, Ross Evan Pivovar

Mechanical and Aerospace Engineering Theses - Archive

Porous coatings have long been a method to enhance boiling heat transfer. Previous researchers have thoroughly explained most of the physics behind the enhancement, but some holes still exist. Correlations, setup to predict nucleate boiling, are often only accurate in specific scenarios. CHF correlations that take into account wettability do not consider microstructure changes that decrease contact angle, but do not enhance CHF. A solution to these problems is presented via the wicking and wetting of liquid on a porous surface. CHF is found to be enhanced with increases in wicking speeds and flow rate. Wetting, measured by apparent contact …


Transient Flow Analysis Of Filling In Pulse Detonation Engine, Veera Venkata Suneel Jinnala Jan 2009

Transient Flow Analysis Of Filling In Pulse Detonation Engine, Veera Venkata Suneel Jinnala

Mechanical and Aerospace Engineering Theses - Archive

The Pulse Detonation Engine (PDE) is considered to be a propulsion system of future air vehicles. The objective of the present study is to model an efficient inlet system for filling the detonation tube completely with the fuel/air mixture. In the present study the filling processes is modeled numerically using CFD code FLUENTTM. Calculations for the gas flow are carried out by solving the Navier-Stokes equations coupled with the k- ? turbulence model. Five different inlet configurations were proposed and simulated in both two-dimensionally and three-dimensionally. The model with an orifice plate at the inlets ensured the desired optimum results. …


Guidance Of Receiver Aircraft To Rendezvous With Tanker In The Presence Of Wind, Jane-Wit Kampoon Jan 2009

Guidance Of Receiver Aircraft To Rendezvous With Tanker In The Presence Of Wind, Jane-Wit Kampoon

Mechanical and Aerospace Engineering Theses - Archive

This thesis work addresses the problem of aircraft rendezvous in the presence of prevailing wind for automated aerial refueling operations. A modified point-parallel rendezvous procedure is defined. The tanker aircraft performs a racetrack maneuver along a pre-specified refueling orbit. The receiver aircraft enters the refueling area through a fixed point and flies along the refueling line that is aligned with on of the straight legs of the race track. It is the responsibility to meet the tanker at the rendezvous point. A virtual target is used to define the trajectory of the refueling orbit. A nonlinear guidance algorithm is used …


On-Chip Liquid-Liquid Extraction And Separation Using Digital Microfluidics, Praveen Kunchala Jan 2009

On-Chip Liquid-Liquid Extraction And Separation Using Digital Microfluidics, Praveen Kunchala

Mechanical and Aerospace Engineering Theses - Archive

In this thesis, on-chip liquid-liquid microextraction and separation using electrowetting on dielectric (EWOD) digital microfluidics was demonstrated by considering room temperature ionic liquid (RTIL) and DI water as two liquid phases, which form immiscible interface with each other. Room temperature ionic liquids (RTILs) have been actively investigated as replacements for the organic solvents and various "task-specific" ionic liquids (TSIL) are being developed which exhibit many attractive properties such as selectivity to specific biomolecules. Liquid-liquid extraction and separation using EWOD digital microfluidic device with model extraction experiments have been demonstrated, one was extraction of organic dye from RTIL (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf2]) …


Algorithm Developement For Adaptive Grid Generation Using Galerkin Finite Element Method, Monalkumar Patel Jan 2009

Algorithm Developement For Adaptive Grid Generation Using Galerkin Finite Element Method, Monalkumar Patel

Mechanical and Aerospace Engineering Theses - Archive

The adaptive grid concept is developed in order to achieve more accurate and stable results for the numerical simulations of Partial Differential Equations (PDEs). There are two main types of strategies used for adaptive grids: local refinement by increasing the number of elements (h-refinement) and deforming grids where the number of elements remains fixed (r-refinement). The h-refinement method requires inserting additional elements and nodes in a certain region of the mesh. This significantly affects the software data structure and makes programming more difficult. To maintain the same data structure, the method must delete the same number of nodes from another …


Finite Element Analysis Of Bio-Heat Transfer For Magnetic Fluid Hyperthermia Application, Kamalkumar N. Chauhan Jan 2009

Finite Element Analysis Of Bio-Heat Transfer For Magnetic Fluid Hyperthermia Application, Kamalkumar N. Chauhan

Mechanical and Aerospace Engineering Theses - Archive

Finite Element solution for the multi-region bio-heat Equation is present to model magnetic fluid hyperthermia. This study solves the Penne's two dimensional bio-heat equation using finite element method and develops the thermal behavior of the tumor and healthyportion of the composite tissue using low curie nanoparticles.The inner cylinder represents the tumor tissue containing low Curie temperature nanoparticles. Low Curie temperature nanoparticles generate heat due to the Neel and Brownian relaxation when a magnetic field is applied. The outer cylinder represents the healthy tissue.First part of this thesis discusses about the background related to the nanoparticles heat dissipation and finite element …