Mechanical Engineering Commons^™

A Cfd Model Of Mixing In A Microfludic Device For Space Medicine Technology, Terri Lynn Mckay

ETD Archive

The DNA Medicine Institute (DMI) is currently developing a device to be used for blood analysis to satisfy the unique requirements of space medicine applications. A key component of that device is the micromixer, which will ensure mixing and dilution of reagents utilized for detection assays. As part of the device design process, the micromixer was modeled, and the mixing characteristics were analyzed and compared to experimental data. The experimental data was based on a top-view of the system and, lacking data throughout the fluid domain, could not provide the insight into the mixing process that modeling could readily provide. …

Cfd Simulations For The Effect Of Unsteady Wakes On The Boundary Layer Of A Highly Loaded Low Pressure Turbine Airfoil (L1a), Samuel J. Vinci

ETD Archive

The study of a very high lift, low-pressure turbine airfoil in the presence of unsteady wakes was performed computationally and compared against experimental results. The experimental data were collected in a low speed wind tunnel under high (4.9 ) and then low (0.6 ) freestream turbulence intensity conditions on a linear cascade with wakes that were produced from moving rods upstream of the cascade. The flow coefficient was kept at 0.7 while the rod to blade spacing was changed from 1 to 1.6 to 2 blade spacings. These cases were conducted for Reynolds number equal to 25,000 and 50,000, based …

Evaluation Of Lean Systems In Rail Maintenance Operations, Mert Baykut

ETD Archive

The recognized strength of lean systems is its broad applicability to every process industry even though they include some complicated and time-intensive processes. However, this conception is based on the tools and philosophy of Lean systems and the nature of the industry. The required craftsmanship and repetitive processes in rail maintenance define the uniqueness of this research The objective of this thesis was to research the opportunities and applicability for lean systems in rail maintenance. During the research a unique system, consisting of Lean systems and systems engineering tools, is realized and tried to integrate instead of a pure Lean …

A Systems Engineering Reference Model For Fuel Cell Power Systems Development, T. L. Blanchard

ETD Archive

This research was done because today the Fuel Cell (FC) Industry is still in its infancy in spite over one-hundred years of development has transpired. Although hundreds of fuel cell developers, globally have been spawned, in the last ten to twenty years, only a very few are left struggling with their New Product Development (NPD). The entrepreneurs of this type of disruptive technology, as a whole, do not have a systems engineering 'roadmap", or template, which could guide FC technology based power system development efforts to address a more environmentally friendly power generation. Hence their probability of achieving successful commercialization …

Fea Analysis Of Novel Design Of Cylindrical Roller Bearing, Prasanna Subbarao Bhamidipati

ETD Archive

This work presents a finite element stress analysis of a novel design of cylindrical roller. The focus of this study is to create a uniform contact-stress distribution along the length of the roller and to recommend a roller bearing design which is easier to fabricate. The new design relies on creating symmetric cylindrical cavities at both ends of a roller. The cavity is concentric with the main body of the roller. The new roller design reduces overall mass of the typical assembly with helps to improve bearing life and its overall performance. The FEA results published herein shows that new …

Vibratory Behavior Of Rolling Element Bearings: A Lagrangian Approach, Phani Krishna Kalapala

ETD Archive

Vibratory behavior of a rolling element bearing on a horizontal rotor is studied in this work. This Thesis analyzes the dynamics of a typical roller bearing as a result of internal excitations. These internal excitations stem from the geometric deviations of the interacting surfaces from their ideal geometry. Such deviations in turn are the results of either manufacturing limitations or normal wear of the bearing surfaces. Lagrangian approach is implemented to derive the dynamic equations of motion. Matlab is used to solve the equation of motion of governing the vibrations of the system. Parametric studies are conducted to provide results …

Adaptive Sliding Mode Control For Aircraft Engines, Kathryn C. Ebel

ETD Archive

Aircraft engine control has been evolving since its beginning. With advancements in technology more and more control methods are being applied to this area. This thesis presents the design of an adaptive PID sliding mode control (A-SMC) for a turbofan engine. The controller design methodology is presented. Using an aircraft engine simulation environment developed by NASA, called Commercial Modular Aero-Propulsion System Simulation, the developed controller is tested. The results from three simulations are analyzed to investigate the application of this new design scheme. The A-SMC is able to follow the demanded fan speed for short flight simulations. However, some of …

Multivariable Sliding Mode Control Design For Aircraft Engines, Sirirat Sangwian

ETD Archive

Many control theories are used in controlling aircraft engines. However, the multivariablesliding mode control is not yet established in this application even though ithas a lot of potential in dealing with complex and nonlinear systems such as aircraftengines. Therefore, a guideline in developing multivariable sliding mode control law for an aircraft engine is presented in this thesis. The problem of chattering in thesliding mode control is suppressed by the use of the boundary layer method. The controllogic is tested by implementing NASA's Commercial Modular Aero-PropulsionSystem Simulation 40k (C-MAPSS40k). Simulation results are analyzed and comparedto the results obtained from the baseline …

Application Of Active Magnetic Force Actuator For Control Of Flexible Rotor System Vibrations, Volodymyr Mykhaylyshyn

ETD Archive

The purpose of this work was to develop and experimentally demonstrate a novel approach to minimize lateral vibrations of flexible rotor. The applied feed forward control approach employed magnetic force actuator to inject a specially designed force to counteract the rotor unbalance force. By specific selection of frequency and phase as functions of the rotor running speed and rotor natural frequency, the proposed simplified injection waveform has been shown to be effective both in reducing the rotor's vibrations and for hardware implementation. A model of the test rig was constructed using the finite element (FE) method and was validated using …

Probabilistic Structural And Thermal Analysis Of A Gasketed Flange, Atul G. Tanawade

ETD Archive

Performance of a flange joint is characterized mainly by its 'strength' and 'sealing capability'. A number of analytical and experimental studies have been conducted to study these characteristics under internal pressure loading. However, with the advent of new technological trends for high temperature and pressure applications, an increased demand for analysis is recognized. The effect of steady-state thermal loading makes the problem more complex as it leads to combined application of internal pressure and temperature. Structural and thermal analysis of a gasketed flange was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties …

Finite Element Reconstruction Of Real World Aortic Injury In Near-Side Lateral Automotive Crashes With Conceptual Countermeasures, Aditya Neelakanta Belwadi

Wayne State University Dissertations

Traumatic rupture of the aorta (TRA) remains the second most common cause of death associated with motor vehicle crashes after brain injury. On an average, nearly 8,000 people die annually in the United States due to blunt injury to the aorta. It is observed that more than 80% of occupants who suffer an aortic injury die at the scene due to exsanguination into the chest. With the advent of more accurate and established human body finite element (FE) models, FE crash reconstruction methods may become a valuable tool when assessing crash scenarios and occupant injury mechanisms.

The current study is …

Effect Of Mesh Distortion On The Accuracy Of High Order Vorticity-Velocity Cfd Approaches, Anurag Rajan

Dissertations, Master's Theses and Master's Reports - Open

The numerical solution of the incompressible Navier-Stokes equations offers an alternative to experimental analysis of fluid-structure interaction (FSI). We would save a lot of time and effort and help cut back on costs, if we are able to accurately model systems by these numerical solutions. These advantages are even more obvious when considering huge structures like bridges, high rise buildings or even wind turbine blades with diameters as large as 200 meters. The modeling of such processes, however, involves complex multiphysics problems along with complex geometries. This thesis focuses on a novel vorticity-velocity formulation called the Kinematic Laplacian Equation (KLE) …

Test 1999: John Deere 8335rt, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Dynamic Response Of Brain Subjected To Blast Loadings: Influence Of Frequency Ranges, Mehdi S. Chafi, Shailesh G. Ganpule, Linxia Gu, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

Blast wave induced a frequency spectrum and large deformation of the brain tissue. In this study, new material parameters for the brain material are determined from the experimental data pertaining to these large strain amplitudes and wide frequencies ranging (from 0.01 Hz to 10 MHz) using genetic algorithms. Both hyperelastic and viscoelastic behavior of the brain are implemented into 2D finite element models and the dynamic responses of brain are evaluated. The head, composed of triple layers of the skull, including two cortical layers and a middle dipole sponge-like layer, the dura, cerebrospinal fluid (CSF), the pia mater and the …

Preliminary Design Of A Pressurization System For Small Bipropellant Rocket Engines, Steven Stanley

Mechanical and Aerospace Engineering Dissertations - Archive

A study was conducted on the feasibility of developing a device or system that would improve the performance of small, bipropellant rockets through pressurization of the propellants. Due to the limitations in the space industry, namely high development costs and resistance to change, the new approach needed to be as simple and robust as possible. After reviewing several different potential methodologies, a concept was developed from first principles based on small gas turbine engine fuel injection approaches. The concept is simple and has heritage in the field of gas turbine engines, but it is new for the field of rocket …

Analysis Of Pulse Detonation Turbojet Engines, Ronnachai Vutthivithayarak

Mechanical and Aerospace Engineering Dissertations - Archive

Research over the last two decades has shown the potential advantages of pulse detonation engines (PDEs) over existing aero-engines in terms of improved thermodynamics efficiency, improved thrust performance, simplicity of design, and exibility to operate over a wide speed range. The inherently unsteady characteristic of PDEs makes it difficulty to analyze and evaluate their performance. The conventional method that relies on steady-state assumptions cannot be directly applied. PDE studies have to employ unsteady gasdynamics behavior. In this study, the thermodynamic cycle of a PDE, which can be called the ZND cycle, is theoretically analyzed. A parametric analysis of turbojet PDEs …

Mode Truncation Analysis In Forced Response Of Structural Dynamics, Sravan Kumar Neela

Mechanical and Aerospace Engineering Theses - Archive

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 …

Experimental And Numerical Investigation Of Transesterification Of Vegetable Oil With A Continuous Flow Capillary Reactor, Rachaneewan Charoenwat

Mechanical and Aerospace Engineering Dissertations - Archive

Biodiesel, Fatty Acid Methyl Ester (FAME), is a renewable fuel that is a promising alternative to fossil fuels in the future. Biodiesel not only has similar properties to diesel derived from fossil fuel, but it also provides more environmentally friendly due to lower carbon monoxide and sulfur emissions. Biodiesel is composed of methyl esters which can be synthesized from various fatty acid sources with a present of catalyst. Typical feed-stocks include vegetable oils, such as waste cooking oil, animal fats, and even oil from algae. Four primary ways to use vegetable oil as a fuel are direct use, blending with …

Modeling And Control Of Automatic Transmission With Planetary Gears For Shift Quality, Patinya Samanuhut

Mechanical and Aerospace Engineering Dissertations - Archive

Automatic transmission is a major component in a vehicle that transmits the power source from the engine to the drive wheels of the vehicle. To improve fuel economy, reduce emission and enhance driving performance, many researchers have made tremendous efforts on new technologies for automatic transmission with planetary gear sets. Among these new technologies, system dynamics and control methodologies are extremely important tools to realizing the fuel economy, emission and driving performance. This research effort focuses on the modeling and control of an automatic transmission with planetary gear sets. A Lagrange-based method is developed to derive the equations of motion …

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 - Archive

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 …

A One Dimensional Dry Friction Microconveyor Platform: Modelling And Analysis Of Micropart Motion Due To Surface Excitation, Moshin Rizwan

Mechanical and Aerospace Engineering Dissertations - Archive

Many approaches are used for micropart manipulation ranging from individual pick and place to manipulation through a workcell comprising of arrays of actuators. Existing approaches provide discrete actuation and have limitations on the lower bound on the size of the micropart to be handled. In this research, the active surface concept for non-contact micropart manipulation is investigated. The active surface deformation is generated by a set of controlled microactuators and provides for continuous micromanipulation while alleviating limitations of existing approaches. The drastic increase of surface area to volume ratio from macroscale to microscale requires the consideration of surface forces (such …

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 - Archive

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 …

The Analysis And Testing Of The Quaife Torque-Biasing Differential, John W.H. Trout

Mechanical and Aerospace Engineering Theses - Archive

The purpose of this thesis is to analyze and test the Quaife torque biasing differential. The differential was modeled mathematically and equations were formulated. Experiments were then performed on a Formula SAE car to see how the output torque of each axle would react to modified preload torques. The results of these tests were then compared with the mathematical models. Overall, it was found that the there are two equations that govern the differential: one for traction and one for slip, and that the derived model correlates well with the experimental results.

Parametric And Performance Analysis Of A Hybrid Pulse Detonation / Turbofan Engine, Sivarai Amith Kumar

Mechanical and Aerospace Engineering Theses - Archive

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 …

Analytical Parametric Cycle Analysis Of Continuous Rotating Detonation Ejector-Augmented Rocket Engine, Huan V. Cao

Mechanical and Aerospace Engineering Theses - Archive

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 …

Issues On Finite Element Modeling Of Laminated Composite Structures, Farhan Alamgir

Mechanical and Aerospace Engineering Theses - Archive

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 …

Development Of Ultra-High Temperature Material Characterization Capabilities Using Digital Image Correlation Analysis, Julia Elaine Cline

Mechanical and Aerospace Engineering Theses - Archive

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 …

Plate Analysis With Different Geometries And Arbitrary Boundary Conditions, Ashwin Balasubramanian

Mechanical and Aerospace Engineering Theses - Archive

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 …

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 - Archive

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 …

Numerical Analysis Of The Interaction Between A Detonation Wave And Compressible Homogeneous Isotropic Turbulence, Monika Chauhan

Mechanical and Aerospace Engineering Theses - Archive

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 …