Engineering Commons^™

A Methodology For Topology And Lattice Structure Optimization Of A Cargo Drone Motor Mount, Nagadurga Srinivas Sripada

Mechanical and Aerospace Engineering Theses - Archive

This work discusses a CAE driven methodology for designing a lightweight component by performing structural configuration on a given package space, creating a closed surface along this configuration using an interactive geometric modeling tool, and lastly generating lattice members that provide the required stiffness for the structure. The design process is explained starting with topology optimization performed on a single block with specific design constraints. It describes the effect of different parameters on the optimized results and how to analyze these results based on a given volume fraction constraint with the objective of minimizing the compliance. It then talks about …

Region Based Convolutional Neural Networks For Object Detection And Recognition In Adas Application, Sachit Kaul

Mechanical and Aerospace Engineering Theses - Archive

Object Detection and Recognition using Computer Vision has been a very interesting and a challenging field of study from past three decades. Recent advancements in Deep Learning and as well as increase in computational power has reignited the interest of researchers in this field in last decade. Implementing Machine Learning and Computer Vision techniques in scene classification and object localization particularly for automated driving purpose has been a topic of discussion in last half decade and we have seen some brilliant advancements in recent times as self-driving cars are becoming a reality. In this thesis we focus on Region based …

The Design And Linearization Of Flow Control Device And Pressure Forces On Valve, Penchala Sumanth Reddy Challa

Mechanical and Aerospace Engineering Theses - Archive

Emerging technologies are pushing the limits by reducing the size of the nodes, raising the heat densities of packages thereby demanding better thermal management. The cooling power requirement increases drastically when air is used as the cooling medium in high power density servers as air has a low heat transfer coefficient. Very viable replacements for air as the cooling medium are water and oil. Oil is not as widely used as it has its own disadvantages when compared to water. Water has appreciably higher heat transfer coefficient, which helps it to remove heat from the server at a much faster …

Computational Model For Steady State Simulation Of A Solid Oxide Fuel Cell (Sofc) Planar Stack Model Undergoing Reforming Process, Vaibhav Vijay Indulkar

Mechanical and Aerospace Engineering Theses - Archive

Solid Oxide Fuel Cell (SOFC), is a clean and low-pollution technology of generating power of high efficiency. Its applicability for both stationery and transportation power generation systems, adaptability for wide range fuel sources, as wells its process of direct conversion of fuel to energy make it an important source of power generation. An effective design of sub-systems or individual components play a key role in overall working of a plant. Thus, critical analysis at the component level is of importance for the overall plant efficiency. In the present study a heat transfer model of a planar SOFC stack to be …

Reliability Assessment Of Solder Joint Using Bga Package – Megtron 6 Versus Fr4 Printed Circuit Boards Using Drop Testing, Pradnya Chandrakant Mundhe

Mechanical and Aerospace Engineering Theses - Archive

In electronic industry Ball grid array (BGA) package, surface mount technology has been used widely, due to its robust design, high density connections and improved performance. In surface mount technology, solder joints are used to interconnect package and PCB board assembly. High frequency laminates use in PCB boards provides excellent performance for high speed, frequency devices. Nelco 4000-13EPSI, Panasonic Megtron 6, and Rogers 4350B are few popular laminates. Component size reduction and structural complexity because of increasing number of transistors are making it very difficult to protect the packages from mechanical, thermal, and electrical damage. Difference in material properties between …

Computational Morphology Modelling And Mixed Mode Fracture Analysis Of Zrb2/Sic Based Ceramic Nano-Materials Using Molecular Dynamics, Krutarth Shaileshkumar Patel

Mechanical and Aerospace Engineering Theses - Archive

Transition metal carbides, nitrides, and borides are a group of Ultra High-Temperature Ceramic (UHTC). Owing to their remarkable properties of the high melting point, high thermal conductivity and excellent strength at elevated temperature ZrB2 based composites are of high interest for use in the high-temperature environment. It is proved that addition of SiC in ZrB2 can advance composite’s oxidation resistance, mechanical strength, fracture toughness and sintering behavior. Firstly, molecular dynamics is used to simulate crack growth under mixed mode loading in Al, SiC, and ZrB2 single crystals by considering inclined crack under uniaxial tension and crack growth angle are compared …

A Study On The Turbulence Characteristics And Mixing Performance Of Streamwise Vortex Interactions In Supersonic Flow, Cody R. Ground

Mechanical and Aerospace Engineering Dissertations - Archive

The scramjet engine offers the unique capability to enable sustained airbreathing flight at hypersonic speeds. However, in order to reach its full application potential, further technological maturation of several system level components is necessary. One such component is the fuel injection system. The flow conditions characteristic of the scramjet combustor are such that the rate-limiting step in the fuel injection/mixing/combustion process is the mixing of the fuel and air. For this reason, the fuel injection system must be designed with the goal of enhancing the rate of fuel/air mixing. One method that has shown potential to enhance fuel/air mixing in …

Investigation On Metal-Composite Hybrid Flywheels Using Finite Element Method, Ching Huai Wang

Mechanical and Aerospace Engineering Theses - Archive

This research is aimed to investigate the kinetic energy storage of a hybrid metal-composite flywheel rotating at high speeds. The upper limit of energy, which flywheel can supply, is restricted by the strength of material because both energy and stress are proportional to the density of the material and the square of the velocity. Metal flywheels operate at lower rotational speed and supply less energy than the composite flywheels. Composite flywheels have a very high density per unit mass, but lower energy density per unit of the design volume. The ultra-high speed of composite flywheels creates some engineering challenges such …

Reliability Assessment Of Solder Joint Interconnects Of Bga Package-Megtron Series Under Power Cycling, Mahesh Pallapothu

Mechanical and Aerospace Engineering Theses - Archive

Solder joint interconnects are the second level assembly in surface mount interconnection technology. Mismatch in the coefficient of thermal expansion (CTE) between package and substrate or PCB creates failure in solder joints such as excessive warpage, low-k dielectric cracking, solder mask cracking and bump cracking. Conventional accelerated thermal cycling tests are performed to evaluate the Solder Joint Reliability (SJR). But, in everyday application, the package is subjected to Power cycling. Power cycling is the phenomenon where the package experiences non-uniform temperature distribution in the package with the chip as an internal heat generating source when an electronic device is turned …

Effective Thermal Conductivity Of Porous Media By Inverse Heat Transfer Analysis, Oscar Javier Ii Fabela

Mechanical and Aerospace Engineering Theses - Archive

This research describes the application of inverse analysis to estimate the thermal conductivity of a porous material using temperature measurements at the surfaces. Finite volume analysis code is implemented in MATLAB and it is utilized to solve the steady state, axisymmetric heat transfer governing energy equation. The analysis code is coupled with a numerical optimization method and utilized to predict thermal conductivity using the measurements. An experimental setup was developed to test a porous media composed of a mixture of small pellets and air. In experiments, temperature is measured at outer surface of copper tube. These data, serves as input …

Real-Time Minimum Jerk Optimal Trajectory Synthesis And Tracking For Ground Vehicle Applications, Naga Venkata Murali Veerapaneni

Mechanical and Aerospace Engineering Theses - Archive

Research on wheeled mobile robots has been an active research field for several decades with focus on the problems of stability, maneuverability and control. The trajectory generation for wheeled mobile robots is usually handled by considering a smooth function satisfying the boundary conditions. Even though this problem is well posed for several function classes, the real issue occurs in generating a feasible trajectory for the robot which takes into account the constraints of the system. Another problem from the control system perspective is, whether the derived controller is stable for the entire trajectory span to track the given trajectory. The …

Pseudo-Spectral Methods Based Real-Time Optimal Path Planning For Unmanned Ground Vehicles, Denish Kamleshkumar Baman

Mechanical and Aerospace Engineering Theses - Archive

Real-time optimal trajectory design and tracking for autonomous ground vehicles are maturing technologies with the potential to advance mobility by enhancing time and energy efficiency in application such as indoor surveillance robots or planetary exploration rovers. Pseudo-spectral methods based trajectory generation framework provides the desired trajectory which minimizes a prescribed objective function (i.e. minimum time, acceleration, and energy) while satisfying kinodynamics and various types of constraints (i.e. obstacle avoidance and smooth turning at waypoint transitions). In this thesis cyber-physical system architecture is used for the communication between rover-vehicle and the ground station. By using optimal state and control vector from …

Board Level Solder Joint Reliability Assessment Study Of Megtron 6 Vs Fr-4 Under Power Cycling And Thermal Cycling, Jyotirmoy Denria

Mechanical and Aerospace Engineering Theses - Archive

High frequency laminates like Nelco N4000-13, Isola FR408 and Panasonic Megtron 6 packages gained popularity among the industry due to better and improved electrical performances, Improved impedance control, low moisture absorption, good thermal management. High speed laminates are extensively used in high-speed system-level interconnects like high speed network equipment, mainframes, IC testers and high frequency measuring instruments. When an electronic device is turned off and then turned on multiple times, it creates a loading condition called power cycling. The die is the only heat source causing non-uniform temperature distribution. In this paper, the solder joint reliability assessment of Megtron 6 …

Real Time And High Fidelity Quadcopter Tracking System, Tyler Mckay Hall

Computer Engineering

This project was conceived as a desired to have an affordable, flexible and physically compact tracking system for high accuracy spatial and orientation tracking. Specifically, this implementation is focused on providing a low cost motion capture system for future research. It is a tool to enable the further creation of systems that would require the use of accurate placement of landing pads, payload acquires and delivery. This system will provide the quadcopter platform a coordinate system that can be used in addition to GPS.

Field research with quadcopter manufacturers, photographers, agriculture and research organizations were contact and interviewed for information …

Whitespace Exploration, Jason Lloyd Daniel

Master's Theses

As engineering systems grow in complexity so too must the design tools that we use evolve and allow for decision makers to efficiently ask questions of their model and obtain meaningful answers. The process of whitespace exploration has recently been developed to aid in engineering design and provide insight into a design space where traditional design exploration methods may fail. In an effort to further the research and development of whitespace exploration algorithms, a software package called Thalia has been created to allow for automated data collection and experimentation with the whitespace exploration methodology.

In this work, whitespace exploration is …

Model Predictive Power Management Of A Hybrid Electric Propulsion System For Aircraft, Tyler J. Wall

Masters Theses

This work presents the switched optimal power flow control for an aircraft with a hybrid electric propulsion system. The propulsion system is a switched system that operates in either of two modes: (i) battery discharging and electric motor propelling and (ii) battery charging and electric motor generating. The aircraft model and components that form the hybrid propulsion system are modeled as either an algebraic power source/sink or as a dynamic model with appropriate power and state interconnections. With the system model defined, a model predictive control power management strategy is set fourth which minimizes a performance index that includes altitude …

A Design Methodology For Continuous Fiber Additive Manufacturing Using Advanced Computer Aided Engineering Techniques, Nicholas Venter

Mechanical and Aerospace Engineering Theses - Archive

A design methodology for Continuous Carbon Fiber Additive Manufacturing (CCFAM) developed using Computer Aided Engineering (CAE) techniques takes advantage of both the mechanical strength of composite materials and the Fused Filament Fabrication (FFF) method. By performing topology optimization and Finite Element Analysis (FEA) on a load-bearing part, engineers can design much lighter optimized parts that are just as strong as those produced using FFF. This weight reduction is achieved by relying on the mechanical strength of continuous carbon fibers printed alongside a traditional thermoplastic matrix. The FFF additive manufacturing method enables the production of complex shapes, which can match the …

Effect Of Underfill Material & Gap Height On Reliability Of Low-K Large-Die Flip Chip Package Under Thermal Loading, Paul Crisanth

Mechanical and Aerospace Engineering Theses - Archive

The reliability assessment of package assembly is important to predict the performance of any microelectronic devices. Formation of fatigue cracks at the interface between the solder joint and component is the common failure occurring in widely used microelectronic devices. Lead-free solders and advanced silicon process nodes with the low-k dielectrics flip chip package are used and are facing significant reliability challenges. The mismatch of coefficient of thermal expansion (CTE) between the chip and substrate affect solder joint reliability. The underfill encapsulant packaging is widely used to improve chip device reliability. In this paper, we are studying the effect of different …

An Innovative Fuzzy Backstepping Sliding Mode Controller For A Tri-Rotor Unmanned Aerial Vehicle, Shiqian Wang, Jingjuan Zhang, Qian Zhang, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The dynamical model of a Tri-Rotor Unmanned Aerial Vehicle (UAV) is presented in this paper. The Tri-Rotor has three rotors with two fixed-pitch propellers and a tiltable propeller to control the yaw displacement. The model is obtained via the Newton–Euler approach and a nonlinear control strategy called fuzzy backstepping sliding mode control is proposed for the attitude stabilization and altitude tracking of the vehicle. The designed controller consists of a backstepping sliding mode controller and a fuzzy logic controller. For the problem of determining the backstepping sliding mode control coefficients, an optimization method of gradient descent algorithm has been used. …

Optical Flow Method For Blood Flow Velocimetry Based On Digital X-Ray Subtraction Angiography: A Brief Review, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

Detailed blood flow information has been recognized as the key information for diagnosis of vascular diseases, such as vascular stenosis and aneurysms. Optical flow method (OFM) is an emergent technique as a tool to analyze the digital x-ray subtraction angiographic images of blood vessels to obtain the detailed blood flow distribution in vascular systems. A brief review isconstructed to discuss the status, applicability, accuracy and future direction of the optical flow technique in the physical study of vascular flow.

A Comparative Study Of Wooden And Hyrbid Composite Crossarms Of An Electric Utility Pole, Rohit Avadhani

Mechanical and Aerospace Engineering Theses - Archive

Most of the cross arms in the country are made from wood. Wood, although easily accessible, has its own defects. Environmental effects which includes the expansion and contraction of wood over the years which will disrupt its structural integrity, the presence of termites and other insects which dig into wood and destroy it from the inside, Materials wastage when it comes to improving the structural strength by increasing the cross-sectional thickness and height The replacement of wood with composites seems like a logical idea and also a solution to most of the problems. The applications of composites in our day …

Effect Of Solder Voids And Distance To Neutral Point (Dnp) On Sjr Of Wcsp Under Reflow Condition And Thermal Cycling, Aniruddha Doiphode

Mechanical and Aerospace Engineering Theses - Archive

Since the introduction of Chip Scale Packages (CSP’s) in the early 2000s, they have become one of the biggest packaging trends in recent history. There are currently over 50 different types of CSP’s available throughout the industry and the numbers are increasing almost daily. Wafer Level Chip Scale Package’s (WCSP) is kind of CSP’s used widely due to its small form factor which offers efficient use of limited space and miniaturization of the electronic device. On the other hand, small form factor typically incurs greater initial cost in product design and development. In an electronic device, it is equally important …

Strength And Damage Prognosis Of Adhesive Bond And Inter-Ply Hybrid Composites Based On Dielectric Properties, Priyanshu K. Banerjee

Mechanical and Aerospace Engineering Theses - Archive

Composite materials have found their applications in a wide range of industries particularly in the aerospace and automotive sectors. This is because they are comparatively light-weight and provide a much better corrosion and wear resistance as compared to other ceramics and metals. Adhesive bonding can be used to improve the stress distribution between these composite materials. Moreover, adhesive bond decreases the weight and concentration of stresses in the structure. Broadband Dielectric Spectroscopy, BbDS is a robust tool used for analyzing the dielectric properties of a polymer composite. This method can be used to monitor the curing process of the specimen. …

Multiphase Flow Modeling And Analysis Of Phased Filling Process For Pulsed Detonation Engine, Nirmal Kumar Umapathy

Mechanical and Aerospace Engineering Theses - Archive

Filling of reactants into a pulsed detonation engine (PDE) should be carried out quickly because any lengthening of the fill time will lead to an increased cycle time. The fill process and, the purge process constitutes a large proportion of time in a cycle. The purpose of this research was to improve the time of fill by implementing various injection geometries in two injection schemes with five different premixed stoichiometric fuel-air mixture injected at wide range of velocity. The different configurations examined were end wall injection, side wall injection with ports angled and normal to the flow direction and staggered …

An Investigation Of Topology Optimization For Coupled Thermo-Structural Loading For Additive Manufacturing, Vaibhav Shankar Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

This work investigates the ability of topology optimization methods to design multifunctional components with coupled thermo-structural loading for fabrication with additive manufacturing technologies. Topology Optimization is a mathematical approach developed to perform design optimization with the purpose of reducing material usage, while maximizing the structural and thermal performance, in accordance to specific design constraints. Additive manufacturing provides the capability to create internal structures and complex surfaces developed by topology optimization that would not be possible to produce by conventional manufacturing. The more structurally efficient configuration generated by topology optimization and fabricated with additive manufacturing can result in components with improved …

Numerical Study Of Droplet Evaporation, Ritul Gandhi

Mechanical and Aerospace Engineering Theses - Archive

Droplet evaporation plays a vital role in various engineering fields such as air/fuel premixing, inkjet printing and many more. The high rate of power dissipation from the integrated circuits and chips of electronic devices creates a need for cooling it to achieve their optimal functionality. The high rate of cooling can be achieved by thin film evaporation of water by phase change as compared to the air cooling methods. Therefore, the study of droplet evaporation is necessary to understand the underlying physics and effects of different parameters on cooling performance. Numerical study of droplet evaporation has been done by using …

Optimized Thruster Allocation Utilizing Dual Quaternions For The Asteroid Sample Return Mission (Osiris-Rex), Asher Smith

Doctoral Dissertations and Master's Theses

As spacecraft require higher positional accuracy from the attitude control systems, new algorithm developments, along with sensor and actuator resolution and range improvements are necessary to achieve the desired science accuracies. For agile 6-Degrees of freedom (6-DOF) spacecraft with redundancy, the actuators are usually oversized or overpopulated to meet the desired slew requirements. Currently, most spacecraft utilize an over-actuated thruster system to produce 6-DOF control. This thesis presents a simulation of the OSIRIS-REx mission during the descent phase to the asteroid Bennu, with a focus on utilizing dual quaternion dynamics and a newly developed thruster allocation method. The dual quaternion …

Mechanical And Electrical Characterization Of Carbon Fiber/Bucky Paper/Zinc Oxide Hybrid Composites, Suma Ayyagari

Doctoral Dissertations and Master's Theses

The quest for multifunctional carbon fiber reinforced composites (CFRPs) expedited the use of several nano reinforcements such as zinc oxide nanorods (ZnO) and carbon nanotubes (CNTs). Zinc oxide is semi-conductor with good piezoelectric and pyroelectric properties. These properties could be transmitted to CFRPs when a nanophase of ZnO is embedded within CFRPs. In lieu of ZnO nanorods, Bucky paper comprising mat of multiwall-carbon nanotubes (MWCNTs) could be sandwiched in-between laminae to construct a functionally graded composite with elevated electrical and thermal conductivities. In this study, a low temperature ( 90_C) hydrothermal synthesis method was utilized to grow ZnO nanorods on …

Aviation Propulsive Lithium-Ion Battery Packs State-Of-Charge And State-Of-Health Estimations And Propulsive Battery System Weight Analysis, Jingsi Lilly

Doctoral Dissertations and Master's Theses

Aviation propulsive battery pack research is in high demand with the development of electric and hybrid aircraft. Accurate inflight state-of-charge and state-of-health estimations of aviation battery packs still remain challenging. This thesis puts efforts on estimating the state-of-charge, state-of-health, and remaining energy of a lithium- ion propulsive battery pack with a recursive least squares based adaptive estimator. By reading the system measurements (discharging currents and terminal voltages) with persistent excitation, the proposed estimator can determine the present internal parameters of the battery cells and further interpolate them into state-of-charge, state-of-health, and the remaining energy information. The validation results indicate that …

Aerodynamic And Performance Analysis Of A Morphing Helicopter Rotor System, Vinay Gopal Krishnan

Doctoral Dissertations and Master's Theses

The purpose of this study was to investigate the effect of rotor morphing, specifically variable rotor speed and variable blade twist, on various parameters such as the distribution of angle of attack, lift, power, thrust and/or other metrics describing the performance of a helicopter rotor. A MATLAB based blade element theory model was developed and executed for different flight conditions. The model was validated against the flight test data of a UH-60. Effects on power, lift to drag ratio and rotor drag from variations in blade twist, rotor speed, rotor radius and blade chord was analyzed. Morphing cases were applied …