Mechanical Engineering Commons^™

Computational Analyses For Fluid Flow And Heat Transfer In Different Curved Geometries, Carlin Miller Lucente

ETD Archive

Three-dimensional Computational Fluid Dynamics (CFD) models were developed to simulate fluid flow and heat transfer in a variety of helical channel geometries: circular and elliptical. Laminar flow was observed for Reynolds number between 200 and 1000. Code validation was done for developing steady laminar flow in a circular curved channel. The CFD results were compared to previous numerical results to verify that the model was producing valid results. The curve of the channel has a centrifugal effect on the fluid flow creating secondary flow known as Dean cells. This secondary flow moves the location of the maximum axial velocity towards …

Finite Element Analysis Of Spur Gear Set, V.S.N. Karthik Bommisetty

ETD Archive

A Finite Element procedure has been developed in this work to determine the load distribution factor, Km, of the AGMA formula for a set of spur gear. At first, a spur gear with perfect involute is modeled using a 3-D CAD software. The model is them is assembled with shafts having 1, 2, and 3 degree misalignments. The generated 3-D models were in turn imported to ANSYS workbench to calculate the maximum bending and contact stresses using finite element method. The results generated were then compared with the maximum bending stress results obtained for parallel shafts to estimate the Load …

Mathematical Modeling Of Dc Cardiac Ablation, Sowmya Reddy Narala

ETD Archive

This thesis presents a mathematical modeling of the cardiac DC ablation procedure. The model treats the procedure as a one dimensional heat transfer phenomenon taking place across the thickness of the myocardium. The model further considers a constant 37 oC for one of the boundary condition of the affected tissue, and the temperature of the other boundary condition is set to be a time dependent square-pulse variations. The parameters defining this time dependent boundary condition is used to perform parametric studies to predict tissue temperature at different depth of the myocardium. The initial condition of the myocardium prior to the …

A Finite Element Approach To Stress Analysis Of Face Gears, Lokamanya Siva Manohar Rampilla

ETD Archive

Face Gears have alternative gear-teeth configuration compared to Bevel Gears. Face Gear have a standard spur pinion as opposed to a bevel Gear. This work concentrates on modeling of a Face-gear, Meshed with a spur gear, using CAD Software and Finite Elements Analysis. The bending stress developed at the gear teeth is determined. Numerical results are validated using the bending stress developed between two involute spur gears

Modeling, Simulation And Experimental Verification Of An Electric Bicycle With Regenerative Braking, Maulik Kalolia

ETD Archive

Electric bicycles are widely available in user markets. However their use as a daily commuting vehicle is limited due to the need for frequent recharging. This thesis focuses on the mathematical modeling of electrical bicycle with regenerative breaking. Basic bond graphs methods are discussed here to develop state space models for mechatronic systems. A bond graph based mathematical model of an electric bicycle with regeneration is developed in this thesis. Mathematical models are tested in simulation, generating different road scenarios. Parameters required for the simulation are calculated using an experimental setup. The thesis shows the capability of bond graphs to …

Free Convection Along A Vertical Wavy Surface In A Nanofluid, Deepak Ravipati

ETD Archive

The study of this paper is to introduce a boundary layer analysis for the fluid flow and heat transfer characteristics of an incompressible nanofluid along a vertical wavy surface in a nanofluid. The Resulting transformed governing equations are solved numerically by an implicit finite-difference scheme (Keller-Box method). The results are presented for the major parameters including the wave amplitude , buoyancy ratio parameter , Brownian motion parameter , Thermophoresis parameter and Lewis number. A systematic study on the effects of the various parameters of the local frication factor, surface heat transfer rate (Nusselt number) and mass transfer rate (Sherwood number) …

Mountain Bike Wheel Endurance Testing And Modeling, Robin C. Redfield, Cory Sutela

United States Air Force: Publications

Mountain bike wheels may be evaluated for durability and mode of failure using bump drum test machines that subject wheels to simulated rider loads and uneven terrain. These machines may operate at high speeds in order to accelerate failures, particularly during the design and prototype phase of wheel development. This paper describes a mathematical model of the dynamics of a wheel test drum assembly, and the validation of the model using data recorded during a wheel test. This model will subsequently be applied to better understand the key test operating parameters that must be controlled in order to produce repeatable …

Numerical Simulation Of Buoyancy-Driven Turbulent Ventilation In Attic Space Under Winter Conditions, Shimin Wang, Zhigang Shen, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Attic design and construction have significant impacts on residential buildings’ energy performance. In order to understand how passive ventilation rates affect ridge-vent attic’s performance, a two-dimensional steady-state finite volume model is employed to simulate the buoyancy-driven turbulent ventilation and heat transfer in a triangular attic space of a gable-roof residential building under winter conditions. The modeled attic has a pitch of 5/12 and a passive ventilation system, consisting of continuous ridge and soffit vents. The v2f model is used to analyze the turbulent air flow and natural convection heat transfer inside the attic. The effects of ambient air temperature, vent …

Numerical And Experimental Investigation Of Vascular Suture Closure, Linxia Gu, Ananth Ram Mahanth Kasavajhala, Haili Lang, James M. Hammel

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose — In order to optimize the performance of the suture for tissue closure, it is essential to develop strategies for devising new and improved techniques that can visualize and compare various suturing techniques. This paper describes an experimental and numerical investigation on the performance of sutured tissue.

Methods — In the experiments, two pieces of glutaraldehyde cross-linked bovine pericardium were sutured together through simple running suture and tensioned to study the performance of the sutured tissue. During testing, the tension load and the total displacement of the specimen were recorded. The strain field of the specimen was simultaneously captured …

Throughput Analysis And Bottleneck Management Of Production Lines, Hatice Ucar

Wayne State University Dissertations

Companies are increasing their manufacturing excellence in order to stay competitive in the globalizing market. Plants are becoming more complex year by year due to increasing product classes, hardware complexity, etc... The design and operation of manufacturing systems is of greater importance today than it was in the past. Many studies have been carried out on the design and operation of manufacturing systems by academicians and practitioners over the years, however, there is still no agreement on how to best predict and improve the factory performance (Gershwin, 2000). The studies are based on either analytical approaches or simulation-based approaches. Success …

Method For Increasing The Efficiency Of Organic Photovoltaic Cells, Jinsong Huang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention is directed to an organic photovoltaic cell that contains one or more dipole regions generally disposed between an organic active region and the electrodes and a process for producing such an organic photovoltaic cell.

Manufacturing Process Modeling And Application To Intelligent Control, M. Laine Mears, Parakshit Mehta, Mathew Kuttolamadom, Carlos Montes, Joshua Jones, Wesley Salandro, Drew Werner

Publications

This paper reviews the major findings and intellectual contributions made over the past five years through research in the laboratory of Dr. Laine Mears at Clemson University. The focus of the laboratory’s work is in modeling of traditional and novel manufacturing processes, and application of such models to process control through model-based control strategies. Introducing intelligence to the manufacturing process through physical descriptions of the phenomena being controlled allows for more precise control as compared with reactive systems or those with simple feed-forward control schemes. For traditional processes, new approaches to process characterization allow for more precise control. For novel …

Passive Wireless Antenna Sensors For Crack Detection And Shear/Compression Sensing, Irshad Mohammad

Mechanical and Aerospace Engineering Dissertations - Archive

Despite the fact that engineering components and structures are carefully designed against fatigue failures, 50 to 90% of mechanical failures are due to fatigue crack formation. The severity of the failure depends on both the crack length and its orientation with respect to the loading direction. Many types of sensors are available that can detect fatigue crack propagation. But, crack orientation detection has been rarely reported in the literature. We evaluated a patch antenna sensor capable of detecting crack propagation as well as crack orientation changes. The aim of the sensors would be to evaluate the real-time health condition of …

Illustration Of Fundamentals Of Mechanical Vibration Using Computable Document Format, Shiva Deshmukh

Mechanical and Aerospace Engineering Theses - Archive

The main objective of this study is focused on the better understanding of the basic concepts of mechanical vibrations and its free and ready availability to the entire student community all over the globe.In this study the concepts of vibrations are projected in the form of mathematical models. The mathematical models are designed using MATHEMATICA. These models are graphical in nature and can be animated at will. They are compiled and converted to the Computable Document Format referred as CDF.A very special function Manipulate is used in making the models. This function has given the models an ability to compute …

Graph Theoretic Framework Based Cooperative Control And Estimation Of Multiple Uavs For Target Tracking, Mousumi Ahmed

Mechanical and Aerospace Engineering Dissertations - Archive

Designing the control technique for nonlinear dynamic systems is a significant challenge. Approaches to designing a nonlinear controller are studied and an extensive study on backstepping based technique is performed in this research with the purpose of tracking a moving target autonomously. Our main motivation is to explore the controller for cooperative and coordinating unmanned vehicles in a target tracking application.To start with, a general theoretical framework for target tracking is studied and a controller in three dimensional environment for a single UAV is designed. This research is primarily focused on finding a generalized method which can be applied to …

Lumped Parameter Modeling Of Fluid Line Dynamics With Turbulent Flow Conditions, Yi-Wei Huang

Mechanical and Aerospace Engineering Dissertations - Archive

A procedure for obtaining rational polynomial transfer functions representing ordinary differential equations for time domain transient response simulations of systems with fluid transmission lines with incompressible turbulent flow is formulated and presented. The method is based on the use of an inverse frequency least squares algorithm applied to the distributed parameter model for laminar flow with added lumped resistance to match the additional resistance associated with turbulence. Guidelines for using the algorithm are included with focus on the use of weighting parameters, the number of resonant modes to be included, and the bandwidth of the pressure/flow pulsation dynamics in the …

Solution To Three Dimensional Incompressible Navier-Stokes Equations Using Finite Element Method, Shrinivas Ganesh Apte

Mechanical and Aerospace Engineering Theses - Archive

A primitive variable mixed order formulation of finite element method for solving three dimensional incompressible Navier-Stokes equations is presented. The method of weighted residuals is used to obtain the approximate solutions of linear and nonlinear partial differential equations. The physical domain is discretized by using unstructured tetrahedral elements. Unequal order interpolation functions are used for pressure & velocity variables while the temporal discretization is carried out by using an implicit time marching scheme based on finite differencing.One of the major difficulties arising during the finite element solution of the incompressible Navier-Stokes equations is the efficient factorization/preconditioning of the resulting indefinite …

High Enthalpy Characterization Of The Uta Hypersonic Shock Tunnel, Raheem Temitope Bello

Mechanical and Aerospace Engineering Theses - Archive

In hypersonic wind tunnel testing, matching the flow enthalpy conditions for the hypersonic air-breathing corridor is of great importance in order to assure the validity of experimental results. The flow enthalpy of the UTA hypersonic shock tunnel is increased by a shock induced detonation driver. The detonation mixture consist of hydrogen and oxygen in stoichiometric quantities ( 2H2+O2 ? 2H2O). Experimental variations of pressure and the volume of the detonation section were performed to characterize the enthalpy limits, and overall performance of the UTA hypersonic shock tunnel. The UTA HST test section is designed for a nominal Mach number of …

Experimental And Numerical Investigation Of Mass Transfer In Microreactors, Wei-Tsen Han

Mechanical and Aerospace Engineering Dissertations - Archive

In this work, two types of microreactors for reactions have been studied, which were involving multiple fluid phases: liquid-liquid (immiscible liquids) phase and gas-liquid phase. Investigation of mass transfer within reacting flows in microreactors has been carried out in these two multiphase systems. For the liquid-liquid phase, a microfluidic system was designed and fabricated to generate a slug flow pattern of immiscible liquids. This system was used to demonstrate the effect of the flow pattern on mass transfer and the effect on chemical reaction rate for a simple acid-base reaction. The reaction progression was tracked by measuring the pH along …

Experimental Identification Of Force Coefficients Of Hybrid Air Foil Bearings, Yu Ping Wang

Mechanical and Aerospace Engineering Theses - Archive

Successful applications for air foil bearings in small to midsize turbo-machinery have been acknowledged. Air foil bearings do not require oil lubricant thus they are capable of operating under much higher temperature than oil-lubricated bearings and they entail less maintenance costs if well-designed. However, when rotor size increases beyond 100 mm in diameter, reliability becomes an issue due to comparable increase in rotor weight with respect to increase in load capacity of the bearing. Furthermore, dry rubbing during starts and stops also causes concerns due to typical slow acceleration and deceleration characteristics of large turbo-machinery. The concept of hybrid air …

Experimental Feasibility Study Of Radial Injection Cooling Of Three-Pad Radial Air Foil Bearings, Suman K. Shrestha

Mechanical and Aerospace Engineering Theses - Archive

Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing …

Thermal Behavior Of Dielectric Materials During Rapid Heating, Daipayan Sarkar

Mechanical and Aerospace Engineering Theses - Archive

The objective of this research is to understand the temperature variation in dielectric materials of different geometry. The work is divided into three major segments. The Thermal Wave model has been taken into consideration as the classical Fourier law of heat conduction breaks down when a dielectric material of sub-micron geometry is heated rapidly. The first partof the work discusses primarily about the temperature distribution in a semi-infinite dielectric material, followed by the temperature profile in a finite body (plate) and finally mathematical formulation is presented for a two-layered body. The thermal wave equation is used because in dielectric materials …

Mitigation Of Hot-Spots In High-End Microprocessors Using Bulk And Thin Film Thermoelectric Coolers, Agat Hirachan

Mechanical and Aerospace Engineering Theses - Archive

Due to localized high heat fluxes, hot-spots are created in silicon chips. Cooling of the hot-spots is one of the major thermal challenges in today's integrated circuit (IC) industry. Many researches have been conducted to find ways to cool hot-spots using different techniques as uniform heating is highly desired. First part of the thesis focuses on cooling of hot-spot using conventional thermoelectric cooler (Melcor_CP1.0-31-05L.1) and a micro heat pipe. A chip package with conventional integrated heat spreader and heat sink was designed. Hot-spot was created at the center of the silicon die with background heat at rest of the area. …

Dynamic Performance Of Offset-Preloaded Two Pad Foil Bearings, Shrikant Ashok Yadav

Mechanical and Aerospace Engineering Theses - Archive

Commercial application of the air foil bearing (AFB) in microturbomachinary have been acknowledged. Absence of external pressurizing and lubricating system makes them light and compact. Simple construction, low friction drag and reliability at high speed operations are few more advantages of the AFBs. With all these advantages AFB proves to be the suitable option for oil-free small turbomachinery which includes micro gas turbines with shaft power less than 1000hp. Micro gas turbine generators are typically two shaft configuration with power generation capacity less than 500KW. Although many micro gas turbines with AFBs have been developed, due to the proprietary nature …

Dynamic Mode Decomposition Of Detonation Waves, Rahul Kumar

Mechanical and Aerospace Engineering Theses - Archive

Dynamic mode decomposition is applied to study the self-excited fluctuations supported by transversely unstable detonations. The focus of this study is on the effect of forcing on the limit cycle solutions. Using DMD, only the most coherent modes are analyzed. The most coherent modes in this case are the fundamental and the fourth harmonic. The analysis is based on the coherency of the self-excited detonation modes due to turbulence. Analysis reveals coherency is significantly affected with a turbulent Mach number greater than 0.3 and also the regions downstream of the shock are more affected by turbulence than the region just …

Trajectory Generation And Constrained Control Of Quadrotors, Carlos Alberto Tule

Mechanical and Aerospace Engineering Theses - Archive

Unmanned Aerial Systems, although still in early development, are expected to grow in both the military and civil sectors. As part of the UAV sector, the quadrotor helicopter platform has been receiving a lot of interest from various academic and research institutions because of their simplistic design and low cost to manufacture, yet remaining a challenging platform to control. Four different controllers were derived for the trajectory generation and constrained control of a quadrotor platform. The rst approach involves the linear version of the Model Predictive Control (MPC) algorithm to solve the state constrained optimization problem. The second approach uses …

Stress Analysis In Curved Composite Due To Thermal Loading, Jared Cornelius Polk

Mechanical and Aerospace Engineering Theses - Archive

Many structures in aircraft, cars, trucks, ships, machines, tools, bridges, and buildings, consist of curved sections. These sections vary from straight line segments that have curvature at either one or both ends, segments with compound curvatures, segments with two mutually perpendicular curvatures or Gaussian curvatures, and segments with a simple curvature. With the advancements made in multi-purpose composites over the past 60 years, composites slowly but steadily have been appearing in these various vehicles, compound structures, and buildings. These composite sections provide added benefits over isotropic, polymeric, and ceramic materials by generally having a higher specific strength, higher specific stiffnesses, …

Using Gpu-Based Computing To Accelerate Finite Element Problems, Jacob Watt

Mechanical and Aerospace Engineering Theses - Archive

Historically Graphics Processing Units (GPU) have been used for offloading graphical visualization and made popular in use for video games, but with the development of NVIDIA's CUDA architecture and programing language there has been an increase in the use of GPUs in general purpose (GPGPU) programing. Problems involving large systems of linear equations, such as the Finite Element Analysis (FEA), can benefit greatly from the parallel computing capabilities of GPUs. In my thesis I will solve Poisson's equation and discuss the advantages and disadvantages of the massively parallel environment of GPUs. I will show that on a unstructured grid that …

Determination Of Factors To Improve Effectiveness Of Triangulation Members For A Formula Sae Race Car Frame, Vikram Nair

Mechanical and Aerospace Engineering Theses - Archive

This thesis suggests which factors have significant effect on the torsional and flexural stiffness of a space frame without contributing excessively to its weight. These factors are used as design variables to display the interaction plots generated by performing a Design of Experiments (DOE) using the Hyperstudy tool in Hyperworks by Altair®. The DOE will also provide a mathematical model which can help predict the responses by varying several factors in the design. The node - element models are created in ANSYS classic and are analyzed for various load cases that are representative of the loads on a formula SAE …

Characterization Of Uta Hypersonic Shock Tunnel, Derek Glenn Leamon

Mechanical and Aerospace Engineering Theses - Archive

Characterization of a hypersonic shock tunnel was performed under low enthalpy conditions. A rake was designed and fabricated to measure pitot pressure and heat flux at three axial locations in the test section. Pitot pressures at three locations provided an indication of the inviscid core. Thin film RTD sensors with a fast response time were fabricated to measure the heat flux under these low enthalpy conditions. The Cook-Felderman algorithm was used to estimate the heat flux from the temperature history. Results for the first millisecond of test time showed a probe tip surface temperature increase of 15-20 K and a …