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Plate Analysis With Different Geometries And Arbitrary Boundary Conditions, Ashwin Balasubramanian
Plate Analysis With Different Geometries And Arbitrary Boundary Conditions, Ashwin Balasubramanian
Mechanical and Aerospace Engineering Theses
This thesis work deals with the study of plates with various geometries and different boundary conditions. The method of study is carried out mainly using the Galerkin method combined with the help of the symbolic algebraic software, Mathematica. In this thesis, flat plates with rectangular and triangular geometries are subjected to uniform load acting normal to their surfaces. The lateral deflection of the plates is expressed in a series of polynomials which satisfy the homogenous boundary conditions. Mathematica is used in handling the algebraic operations to solve for the coefficients and generating the trial functions. The maximum deflection of the …
Airfoil-Shaped Extension-Twist-Coupled Composite Star-Beams For Rotor Blade Tip Applications, Sthanu Mahadev
Airfoil-Shaped Extension-Twist-Coupled Composite Star-Beams For Rotor Blade Tip Applications, Sthanu Mahadev
Mechanical and Aerospace Engineering Theses
Rotorcraft blade tips provide the most effective region for aerodynamic control. Rotor blade airloads are proportional to dynamic pressure and as a consequence are typically the highest in the distal blade tip region. Therefore, blade control using aerodynamic forces and moments is most effectively accomplished over the distal region of the blade. Composite materials represent the preferred material option for modern rotor blade design, especially in the field of rotorcraft and wind energy, due to superior strength-to-weight ratio, fatigue resistance and their ability to be easily tailored to incorporate different coupling (bend-twist, extension-twist, etc.) among elastic modes of deformation within …
Filling Of Methane/Air Mixture In A Tube For Pulse Detonation Engines, Shravani Dwarakapally
Filling Of Methane/Air Mixture In A Tube For Pulse Detonation Engines, Shravani Dwarakapally
Mechanical and Aerospace Engineering Theses
In pulse detonation engines, filling is a time consuming process; reducing these times will help to increase the frequency. The filling of a detonation tube, 1 m long tube with an internal diameter of 101.6 mm, closed at one end and opened at the other, was studied using the unsteady flow solver methane and air nominally at STP· Three cases were examined: (i) a 25.4 mm diameter port at the center of the closed end, (ii) nine ports of 25.4 mm diameter, one at the center of the closed end and eight distributed in two diametrically opposite rows, equally, four …
Preliminary Design Of Mesoscale Turbocompressor And Rotordynamics Tests Of Rotor Bearing System, Md Saddam Hossain
Preliminary Design Of Mesoscale Turbocompressor And Rotordynamics Tests Of Rotor Bearing System, Md Saddam Hossain
Mechanical and Aerospace Engineering Theses
A mesoscale turbocompressor spinning above 500,000 RPM is evolutionary technology for micro turbochargers, turbo blowers, turbo compressors, micro-gas turbines, auxiliary power units, etc for automotive, aerospace, and fuel cell industries. Objectives of this work are:1) to evaluate different air foil bearings designed for the intended applications, and 2) to design & perform CFD analysis of a micro-compressor. CFD analysis of shrouded 3-D micro compressor was conducted using Ansys Bladegen as blade generation tool, ICEM CFD as mesh generation tool, and CFS as main solver for different design and off design cases and also for different number of blades. Comprehensive experimental …
Design Optimization Of A Wind Turbine Blade, Bharath Koratagere Srinivasa Raju
Design Optimization Of A Wind Turbine Blade, Bharath Koratagere Srinivasa Raju
Mechanical and Aerospace Engineering Theses
This work focuses on designing a blade of 45 meters in length that produces a power of 1.6 MW. The design of the blade was done using the Blade Element Momentum theory and the Prandtl's tip loss factor was used. The aerodynamic loads and differential power at are tabulated and plotted.The finite element method for analysis of the blade is used. As the chord lengths vary decreasingly along the blade radii in order to use the simple beam theory the breath and height of the blade is considered as a function of the chord length, hence the analysis is done …
Parametric Analysis Of A Detonation-Type Turbofan, Yashwanth M. Swamy
Parametric Analysis Of A Detonation-Type Turbofan, Yashwanth M. Swamy
Mechanical and Aerospace Engineering Theses
A new type of turbofan which detonates a fuel-air mixture was theoretically found to perform better than a conventional turbofan. A continuous detonation process is described and considered inside the core of the turbofan. The detonation-type turbofan needs certain modifications to detonate the fuel-air mixture at the core of the turbofan, namely, an annular detonation chamber to achieve continuous detonation. A parametric analysis of the new detonation-type turbofan was developed and used to calculate the performance parameters.
Analysis Of Laminated Tubular Structure Under Torsion, Thana Chomtid
Analysis Of Laminated Tubular Structure Under Torsion, Thana Chomtid
Mechanical and Aerospace Engineering Theses
Laminated composite shells in particular are prominent in bearing various types of loads and are hence used in many engineering structures. The analysis of laminated composites is quite complicated since the material behavior is anisotropic, which gets further intensified in the analysis of complex structures like tubular structures. Finite element method is a useful method for evaluating and conducting the behavior of thin laminated tubular structure subjected to torsion. In this study, the behavior of shear stress versus angle along the laminated tubular structure cross section was conducted in varies radius ratio which are 1, 0.8, 0.6, 0.4, and 0.2 …
Consideration Of Compressibility Effects For Applied-Back-Pressure Dynamic Well Control Response To A Gas Kick In Managed Pressure Drilling Operations, William Alexander Bacon
Consideration Of Compressibility Effects For Applied-Back-Pressure Dynamic Well Control Response To A Gas Kick In Managed Pressure Drilling Operations, William Alexander Bacon
Mechanical and Aerospace Engineering Theses
Managed Pressure Drilling (MPD) operations offer the ability to control a relatively small gas kick dynamically, without shutting in the well using blowout preventers. One currently employed method of dynamic well control uses applied-back-pressure to force flow exiting the wellbore to equal flow entering the drill-pipe, which is taken as an indication that the influx has stopped. However, for flow out equals flow in to imply influx cessation, the assumption of incompressibility of fluid in the wellbore is necessary. When fluid compressibility is appreciable, solely ensuring flow rate continuity does not necessarily imply influx cessation. The period of "dynamic well …
Nonlinear Finite Element Analysis Of Columns, Rajkiran Muppavarapu
Nonlinear Finite Element Analysis Of Columns, Rajkiran Muppavarapu
Mechanical and Aerospace Engineering Theses
In many engineering applications structural components are considered to be beams or columns subjected to a range of external loads such as dead weight, wind, temperature changes etc.In this work a mathematical model has been developed for a sports lighting tower considering it to be a cantilever beam with large deformation. The concept of non-linear P-Delta analysis is applied to the column. Using this model, a tower analysis tool was developed in MATLAB. Using this tool various design alternatives can be examined to evaluate their suitability to a particular task.A number of example problems from the available literature were solved …
Development Of Ultra-High Temperature Material Characterization Capabilities Using Digital Image Correlation Analysis, Julia Elaine Cline
Development Of Ultra-High Temperature Material Characterization Capabilities Using Digital Image Correlation Analysis, Julia Elaine Cline
Mechanical and Aerospace Engineering Theses
Ultra-high temperature deformation measurements are required to characterize the thermo-mechanical response of material systems for thermal protection systems for aerospace applications. The use of conventional surface-contacting strain measurement techniques is not practical in elevated temperature conditions. Technological advancements in digital imaging provide impetus to measure full-field displacement and determine strain fields with sub-pixel accuracy by image processing. In this work, an Instron electromechanical axial testing machine with a custom-designed high temperature gripping mechanism is used to apply quasi-static tensile loads to graphite specimens heated to 2000°F (1093?C). Specimen heating via Joule effect is achieved and maintained with a custom-designed temperature …
Algebraic Solution To The Planar Rigid Body Impact Problem, Drew Morgan
Algebraic Solution To The Planar Rigid Body Impact Problem, Drew Morgan
Mechanical and Aerospace Engineering Theses
For systems of rigid bodies that undergo impacts, a series of closed-form equations are developed to solve for post-impact velocities which simulate a real-world (energy-consistent) interaction. The analysis is based in the impulse domain, and requires that the surface interaction be characterizable by Coulomb friction and an energetic coefficient of restitution. No iteration, optimization, or numerical methods are used.
Issues On Finite Element Modeling Of Laminated Composite Structures, Farhan Alamgir
Issues On Finite Element Modeling Of Laminated Composite Structures, Farhan Alamgir
Mechanical and Aerospace Engineering Theses
Composite structures have been used widely in aviation industries and civil construction field because of their high specific stiffness, high specific strength and directional dependent properties. When using finite element method to analyze these structures, special attention of modeling is required. This thesis addresses the effect of layer stresses and displacements of a laminate under loading due to element meshing, boundary constraints and material properties used in modeling of composite structures. This study also includes the investigation of the magnitude and location of the layer peak stresses on modeling the laminate with a hole. It is concluded that special characteristics …
Analytical Parametric Cycle Analysis Of Continuous Rotating Detonation Ejector-Augmented Rocket Engine, Huan V. Cao
Analytical Parametric Cycle Analysis Of Continuous Rotating Detonation Ejector-Augmented Rocket Engine, Huan V. Cao
Mechanical and Aerospace Engineering Theses
An analytical parametric cycle analysis model for the continuous rotating detonation wave ejector-augmented rocket was developed to estimate and evaluate the maximum potential performance that the continuous rotating detonation wave rocket (CRDWR) itself can provide in an ejector ramjet as well as the two-stage rocket for low earth orbit (LEO). This was done by integrating Bykovskii's model for CRDWR with Heiser & Pratt's modified ejector ramjet and their transatmospheric performance model. The performance results of this unique engine in comparison to a regular rocket counterpart were evaluated primarily in terms of specific thrust and specific impulse with respect to flight …
Stress Analysis For A Three Phase Plate With A Concentric Circular Inclusion By Deriving An Airy Stress Function, Abhishek Kunchala
Stress Analysis For A Three Phase Plate With A Concentric Circular Inclusion By Deriving An Airy Stress Function, Abhishek Kunchala
Mechanical and Aerospace Engineering Theses
This thesis derives the Airy stress function for a three phase plate that consists of two concentric circular inclusions and a matrix phase. It incorporates the elastic property of each phase as well as the geometry of the inclusions. An Airy stress function has been derived that satisfies the continuity conditions of the displacement and traction across the phase interface precisely. The obtained results are new and could not have been possible without a computer algebra system (Mathematica).
Numerical Study Of Drop Formation From Dripping To Jetting, Allouah Kadjo
Numerical Study Of Drop Formation From Dripping To Jetting, Allouah Kadjo
Mechanical and Aerospace Engineering Theses
The formation of liquid droplet from a capillary tube has been examined using numerical simulations. The dimensions of the capillary tube and the flow velocity have been varied to observe the regimes of drop formation. There are three main regimes of drop formation, which are the periodic dripping, the dripping faucet and the jetting regimes. The mechanism of drop formation changes from one regime to another and involves different parameters. A particular emphasis has been placed on the velocity limits between the different regimes and the critical role played by instabilities in the generation of satellite drops. The algorithm used …
Control Of Airship Motion In The Presence Of Wind, Jatuporn Nakpiam
Control Of Airship Motion In The Presence Of Wind, Jatuporn Nakpiam
Mechanical and Aerospace Engineering Theses
This research effort develops a guidance and control system for a small airship to fly through assigned waypoints in the three dimensional space with a desired speed in the presence of wind and wind gust. In the control system development and validation, a simulation environment based on the nonlinear 6-DOF model of an airship, including the effect of the wind, is used. The airship has five control variables, the main thrust, the main thrust angle, the tail thrust, elevator and rudder deflections. The effectiveness of the elevator and rudder degrades as the speed of the airship decreases. The controller design …
Buckling Analysis Of Thin Plates With Or Without A Hole Under Arbitrary Boundary Conditions Using The Galerkin Method, Srider Thirupachoor Comerica
Buckling Analysis Of Thin Plates With Or Without A Hole Under Arbitrary Boundary Conditions Using The Galerkin Method, Srider Thirupachoor Comerica
Mechanical and Aerospace Engineering Theses
This thesis demonstrates how to find the critical buckling load value of thin plates with or without a hole under different boundary conditions using the Galerkin method. The use of symbolic software is essential due to the lengthy computations involved because of the complexity of the problems. Firstly, the lateral deflection of the plate is expressed in a series of polynomials each of which satisfies the given boundary conditions. Then by using the Galerkin method, the coefficients of these polynomials are found and with the help of symbolic algebra system, the matrices for the corresponding eigenvalue problem are built from …
Adaptation Of Digital Datcom Into A Conceptual Design Process, Brandon Watters
Adaptation Of Digital Datcom Into A Conceptual Design Process, Brandon Watters
Mechanical and Aerospace Engineering Theses
As implied with open-ended `design decision-making' there are multiple prospective conventional and unconventional aircraft solution concepts able to satisfy a given mission specification. The task of defining, assessing and selecting prospective options for the mission at hand is the primary purpose of the aircraft conceptual design (CD) phase. In addition, conceptual design tends to be fast paced and an iterative process structure that requires a quick design-response. This leads the aircraft designer to simplified analysis techniques that focus on the impact (trends and sensitivities) of a new technology on the design. Correctly predicting these trends and sensitivities can be difficult. …
Design And Modeling Techniques For Cooling Of Telecommunication Systems, Naveen Kannan
Design And Modeling Techniques For Cooling Of Telecommunication Systems, Naveen Kannan
Mechanical and Aerospace Engineering Theses
Conventional data centers are extremely large buildings that have complex power distribution and cooling systems. These traditional brick and mortar data centers employ relatively expensive cooling systems and are inefficient. It has in turn led to an increase in construction and operational costs. These inefficiencies of traditional data centers can be overcome by partitioning the server load into modular sections which can be deployed, powered and cooled depending on availability and requirement. Furthermore, improvements in efficiency and operational costs can be achieved by employing "free cooling" to cool the IT equipment. Free cooling involves the introduction of outside air through …
High Speed Edgewise Rotor Computational Analysis And Optimization At High Inflow Velocities Achieved Through Forward Mast Tilt, Cory Michael Hitte
High Speed Edgewise Rotor Computational Analysis And Optimization At High Inflow Velocities Achieved Through Forward Mast Tilt, Cory Michael Hitte
Mechanical and Aerospace Engineering Theses
Increased forward flight speed has long been the desire of the rotorcraft industry. Novel designs, such as compounds and tilt rotors have allowed for speed envelope expansion, but not without incurring performance hindrances unique to each configuration. Designs that utilize low disc loading edgewise rotors, which offer efficient flight at high speeds while maintaining hover performance, are desirable. Such designs require increased flapping capability and/or mast tilt in order to achieve the necessary thrust orientation required for overcoming aircraft drag. The combination of speed and thrust vector inclination yields a relatively undocumented region of rotorcraft performance. In particular, the effects …
Performance Optimization Of Multi-Core Processors Using Core Hopping - Thermal And Structural, Sunil Lingampalli
Performance Optimization Of Multi-Core Processors Using Core Hopping - Thermal And Structural, Sunil Lingampalli
Mechanical and Aerospace Engineering Theses
As the work load on the single core processor increases, it's processing speed increases resulting in increased power densities and die temperatures. The increase in die temperature results in decreased performance and reliability and increased leakage currents and cooling costs. In order to decrease the work load and the cooling cost on the single core processor, multi-core processors have been implemented. Multicore Processors also known as Chip Multi Processors (CMP's) are the processors which contain two or more independent cores on a chip. In CMPs, if one core reaches its critical temperature, the workload is transferred to the other. This …
Numerical Modeling Of A Parallel Plate Electrowetting-On-Dielectric (Ewod) Device, Kevin Tully
Numerical Modeling Of A Parallel Plate Electrowetting-On-Dielectric (Ewod) Device, Kevin Tully
Mechanical and Aerospace Engineering Theses
Numerical modeling and simulations have been performed in this study that focuses on modeling the fluid dynamics of an Electrowetting-on-Dielectric (EWOD) device. The case to be modeled in the present study is a droplet cutting problem where a droplet is sandwiched between two plates of Teflon and an electrical actuation will cause the droplet to cut or split into two smaller droplets. A finite difference method has been used to solve the Navier-Stokes equations, along with the continuity equation. An algorithm used for tracking the free surface is the Volume of Fluid (VOF) method. Along with using the VOF method …
Evaporative Cooling Performance Of A Brazed Microporous Coating On An Aluminum Surface, Ryan M. King
Evaporative Cooling Performance Of A Brazed Microporous Coating On An Aluminum Surface, Ryan M. King
Mechanical and Aerospace Engineering Theses
The effect of an aluminum microporous coating on evaporative cooling performance was studied using distilled water as the working fluid. The aluminum microporous coating was fabricated by brazing aluminum particles to an aluminum substrate. Microporous coating thicknesses of 175 µm ± 20 µm, 270 µm ± 20 µm, and 900 µm ± 90 µm, and average aluminum particle sizes of 27 µm, 70 µm and 114 µm were used in a parametric study to determine the optimum aluminum microporous coating. A hot water treatment maximized the wickability of the microporous coating. Wickability was measured by vertical dipping of the coating. …
Numerical Analysis Of The Interaction Between A Detonation Wave And Compressible Homogeneous Isotropic Turbulence, Monika Chauhan
Numerical Analysis Of The Interaction Between A Detonation Wave And Compressible Homogeneous Isotropic Turbulence, Monika Chauhan
Mechanical and Aerospace Engineering Theses
A numerical study was performed to investigate the effect of preshock turbulence on the detonation wave properties. A direct numerical simulation was performed on the chemically reactive Navier-Stokes equations using a Runge-Kutta scheme and a fifth-order WENO spatial discretization. We performed a direct numerical simulation (DNS) which belongs to the domain of Computational Fluid Dynamics (CFD), of the fluid mechanics equations in three dimensions to determine the fine scale evolution. A simple one-step chemical kinetics model was used in the study.The main objective of the research is to examine the behavior of the turbulence when subjected to a strong shock …
Mode Truncation Analysis In Forced Response Of Structural Dynamics, Sravan Kumar Neela
Mode Truncation Analysis In Forced Response Of Structural Dynamics, Sravan Kumar Neela
Mechanical and Aerospace Engineering Theses
Mode truncation in Modal analysis is an important problem and should be addressed with an effective truncation criterion. The truncation errors are considered as error forces and these error limits can be used to select the number of modes in the solution. Usually frequency based approach is used in selection of modes. But this method ignores the error forces in truncation and not effective if the cutoff frequency is greater than highest natural mode. An effective criterion would limit error forces, thereby minimizing errors in the response solution. To overcome the inaccuracies due to truncation, Mode Truncation Augmentation was used …
Stable Reference Trajectory Modification For Handling Actuator Failure In Control Systems, Ifeolu Olalekan Ogunleye
Stable Reference Trajectory Modification For Handling Actuator Failure In Control Systems, Ifeolu Olalekan Ogunleye
Mechanical and Aerospace Engineering Theses
The issue of rapidly reconfiguring the reference trajectory under unanticipated actuator failures in order to regain lost performance or aircraft handling qualities is explored. The failures detected in real-time are compensated for by ensuring the input to the system reflects current system conditions. This thesis will also show that only the general structure of the failed system component is needed to achieve successful failure detection and reference trajectory reconfiguration. This approach allows the nominal control structure to remain unchanged in the presence of change flight and system conditions. Acceptable system performance is recovered by detecting the actuator failures in real-time. …
Finite Element Based Stability Constrained Weight Minimization Of Sandwich Composite Ducts For Airship Applications, Urmi B. Khode
Finite Element Based Stability Constrained Weight Minimization Of Sandwich Composite Ducts For Airship Applications, Urmi B. Khode
Mechanical and Aerospace Engineering Theses
High Altitude Long Endurance (HALE) airships are platform of interest due to their persistent observation and persistent communication capabilities. A novel HALE airship design configuration incorporates a composite sandwich propulsive hull duct between the front and the back of the hull for significant drag reduction via blown wake effects. The sandwich composite shell duct is subjected to hull pressure on its outer walls and flow suction on its inner walls which result in in-plane wall compressive stress, which may cause duct buckling. An approach based upon finite element stability analysis combined with a ply layup and foam thickness determination weight …
Feasibility Study Of T700 Rotorcraft Engine Rotor Supported By Hybrid Air Foil Bearings, Mahesh Kumar Varrey
Feasibility Study Of T700 Rotorcraft Engine Rotor Supported By Hybrid Air Foil Bearings, Mahesh Kumar Varrey
Mechanical and Aerospace Engineering Theses
A potential solution towards light weighted and simple structured turbomachinery lies in elimination of oil-lubrication system. These promising benefits of oil-free turbomachinery have demanded extensive research in the field of small turbomachinery, leading to the development of different types of oil free bearings. Air foil bearings (AFBs) are one of the oil-free bearings with many advantages over others. AFBs have simple construction, greater service life and reduced maintenance. Their superior dynamic performance compared to traditional rigid surface bearings is an added advantage. Implementation of these foil bearings in the rotorcraft propulsion system decreases the total weight of the engine setup, …
Static And Dynamic Calibration Of A Multi-Component Sidewall Force Balance For A Transonic Ludwieg Tube Wind Tunnel, Michael Gerard Werling
Static And Dynamic Calibration Of A Multi-Component Sidewall Force Balance For A Transonic Ludwieg Tube Wind Tunnel, Michael Gerard Werling
Mechanical and Aerospace Engineering Theses
Experimentation involving transonic flow requires replicating not only the Mach number but also the Reynolds number. Improper matching of the Reynolds number affects the interaction between the shocks and boundary layer on the surface of an airfoil, moving the position of the shock and altering the downstream flow field. Both Mach and Reynolds numbers have a large influence on the lift and drag characteristics of airfoils, amongst other aerodynamic effects, within the transonic regime of flight. A strain-based, multi-component, sidewall force balance was purchased in 1989 specifically for the transonic Ludwieg tunnel at the University of Texas-Arlington, but proper calibration …
Parametric And Performance Analysis Of A Hybrid Pulse Detonation / Turbofan Engine, Sivarai Amith Kumar
Parametric And Performance Analysis Of A Hybrid Pulse Detonation / Turbofan Engine, Sivarai Amith Kumar
Mechanical and Aerospace Engineering Theses
The performance of a hybrid pulse detonation engine (PDE), with the PDE tubes installed in the bypass duct of a turbofan engine is investigated in this study. Performance parameters for the duct burning PDE engine are compared with a baseline turbofan engine. The PDE analysis is based on an updated numerical analysis by Endo-Fujiwara, whereas the turbofan calculations are based on Mattingly's gas turbine model. The calculations were done with MATLAB 2010 as a platform. A mixer analysis was performed for the hybrid engine concept. In the duct burning PDE, the PDE exhaust was mixed with the turbine exhaust prior …