Mechanical Engineering Commons^™

Development Of Guidance, Navigation, And Control Systems For Multi-Spacecraft Assembly In Proximity Operations, Mohammed Ayman Atallah

Theses

This thesis presents the development of Guidance, Navigation, and Control (GNC) algorithms for multi-spacecraft assembly in proximity operations. A 3-DOF mathematical model of spacecraft relative translational motion is derived using the Euler-Lagrange method. Additionally, a 6-DOF mathematical model of spacecraft relative translational and rotational motion is derived using the twistor method, with consideration for the kinematic coupling effect. A new Linear Time-Invariant (LTI) model is developed based on the twistor model, which is utilized in the design of the GNC systems. Both LTI Model Predictive Control (MPC) and Linear Time-Varying (LTV) MPC algorithms are employed to develop Guidance and Control …

Experimental Study Of Central And Side Jet With And Without Chevron Nozzle Exit On Gas Turbine Leading Edge Jet Impingement Cooling, Ahmad Yousef Alqasrawi

Theses

This thesis presents a comprehensive investigation into the application of jet impingement cooling on turbines blade leading edge. Gas turbines are extensively utilized in power generation and aerospace industries, where efficient cooling techniques are crucial to enhance the performance and lifespan of turbine blades. The leading edge of a turbine blade is particularly vulnerable to high-temperature exposure and thermal stresses, making it an essential area for effective cooling strategies. Jet impingement cooling is one of the most effective cooling techniques mostly used in the leading edge of rotating and stationary blades. This study aims to explore the performance of jet …

Design And Fem Modelling Of Mems Capacitive Accelerometer And Gyroscope For Quadcopter/Uav Applications, Shaikha Rashid Alnaqbi

Theses

This study presents the design, simulation, and analysis of Micro Electromechanical Systems (MEMS) sensors, constituting the principal components of MEMS-based Inertial Measurement Units (IMUs). The main objective of the study is to design, simulate and analyze 3-axis capacitive accelerometer and 3-axis gyroscope. The MEMS-based capacitive accelerometers and gyroscope are analyzed using Ansys Workbench. Modal, Static Structural and harmonic analysis are used to obtain resonant frequencies, deformation/stress and profile of amplitude over a wide range of frequencies. Mechanical sensitivity analysis of the designed accelerometer and gyroscope is performed using the Finite Element Method (FEM). Analytical Equations are developed to calculate mechanical …

A Numerical Investigation Realizing The Flow Structure And Heat Transfer Performance Of The Potential Impinging Jets, Mohammed Sami Uddin Khan

Theses

The demand for improvement in the performance of gas turbines has led to the consideration of flows at increasingly high temperatures, but this introduces challenges in terms of maintaining their structural integrity and preventing overheating. To respond to these challenges, gas turbine manufacturers have turned to internal cooling, and jet impingement provides an effective solution for cooling the leading edge of the blades of gas turbines. In this study, the author numerically simulated the cooling performance of the leading edge of the blades of a gas turbine under constant heat flux by using five configurations of jet impingement: a steady …

Thermohydraulic Performance Of 3d Printed Metal Heat Exchanger With Zig-Zag Minichannels, Aysha Rashed Alshamsi

Theses

This work proposes using zig-zag minichannels in heat exchangers for enhancing its performance while operating under balanced (heat capacity ratio of unity) and unbalanced flow (heat capacity ratio of 0.5) conditions for counter flow and parallel flow configurations. The performance of the heat exchangers is quantified in terms of effectiveness and pressure drops and studies are done for hot fluid Reynolds number ranging from 50 to 1500. This work employs a numerical study to investigate the performance of the heat exchanger with zig-zag minichannels.
Simulation is carried out using Fluent module of Ansys Workbench. The model used for simulation consists …

Electrochemical Investigation Of Copperzirconium Based Metallic Glass Cu₅₁Zr₃₀Hf₁₄Ag₅, Tamim Mohammad Ahmad

Theses

This thesis is concerned with the electrochemical investigation of the copper-zirconium

based metallic glass Cu₅₁Zr₃₀Hf₁₄Ag₅. Studying the corrosion behavior of the novel melt-spun metallic glass ribbons contributes to further research on the possibility of building future bio-implants. The objectives of this thesis are to synthesize the metallic glass ribbons which are free from cytotoxic elements using melt spinning technique, verify their amorphous nature using X-ray diffraction method, study the corrosion behavior using Potentiodynamic polarization and Electrochemical Impedance Spectroscopy in different acidic, neutral and basic solutions, and finally examine the surface morphology of …

Aerodynamics And Aeroacoustics Optimization Of Vehicle’S Side Mirror Base And Exhaust Pipe, Moath Nayef Mohamed Zaareer

Theses

This thesis is concerned with studying two different vehicle parts in terms of aerodynamics and aeroacoustics. Two main factors determine the efficiency and luxury of the vehicle, the low aerodynamic forces and low noise emission. The aerodynamic drag coefficient is concerned with how easy a vehicle can travel through the air; the lower the value, the less fuel is needed to move the vehicle forward and less air resistance the vehicle faces. The aerodynamic lift coefficient is related to vehicle ground stability, and the more negative the value is, the higher the vehicle's stability. Moreover, the aeroacoustics is concerned with …

Minimization Of The Weld Distortion By Weld Sequence Optimization Using Artificial Intelligence, Jeyaganesh Devaraj

Theses

The application of dissimilar metal welding processes is increasing nowadays in the automobile, aerospace, marine industry as they not only serve for joint welding for different metals but also assist in repairing and reworking in a simplified manner. Study on optimization of weld parameter to weld a structure is important to have control over the distortion, mass deposition, tensile strength, etc. The present research reports the development and implementation of the Genetic algorithm integrated Artificial Neural Network (GANN) based weld sequence optimization for reducing deformation of dissimilar metal joining using the hot-encode technique. Gas Metal Arc Welding (GMAW) is used …

Towards Automation Of Aluminum Cell Ramming Process, Maryam Salem Mohamed Alkaabi

Theses

Newly installed cathode blocks in an aluminium reduction cell, expand due to a rapid increase of temperature when passing a high current at the start-up of the cell. High thermal stresses may result if cathode blocks are lined without gaps, and this can lead to cracking of the cathodes and failure of the cell. On the other hand, leaving gaps would cause failure due to molten metal infiltration in the gaps. To overcome these problems carbon-based ramming material is used to fill these gaps. Currently ‘Filling’ is carried out manually or partially automated, but this needs to be fully automated …

Flutter Suppression By Active Controller Of A Two-Dimensional Wing With A Flap, Abdallah Tarabulsi

Theses

Flutter is a divergent oscillation of an aeroelastic structure, and one of a family of aeroelastic instability phenomena, that results from the interaction of elastic and inertial forces of the structure with the surrounding aerodynamic forces. Airfoil Flutter is important due to its catastrophic effect on the durability and operational safety of the structure. Traditionally, flutter is prevented within an aircraft's flight envelope using passive approaches such as optimizing stiffness distribution, mass balancing, or modifying geometry during the design phase. Although these methods are effective but they led to heavier airfoil designs. On the other hand, active control methods allow …

Heat Transfer Intensification In Microchannel Heat Sinks (Mchs) - Wavy Channels Embedded With Pin Fins, Anas Mohammad Amin Alkhazaleh

Theses

This work conceptualizes heat sinks for electronics employing wavy/sinusoidal microchannels embedded with pin fins and subsequently analyzes their performance in terms of thermal resistance, pressure drop, maximum chip temperature, and the associated pumping power due to the pressure drop. The conceptualized wavy Microchannel Heat Sink (MCHS) is mathematically modeled using a combination of governing equations including energy equations, continuity equations, and Navier- Stokes equations. The performance of the wavy microchannel heat sink embedded with pin fins is evaluated based on a parametric study covering multiple parameters; microchannel’s amplitude, frequency, hydraulic diameter, pin fins’ diameter, and location, and Reynolds number. The …

Modelling And Control Of A Two-Link Rigid-Flexible Manipulator, Rahma Saeed Rasheed Alnajjar

Theses

The literature lacks data on the reliability of 3D models created by Autodesk Inventor software and imported to MATLAB Simulink software in comparison to mathematically generated models. In this contribution, a two-link rigid-flexible manipulator modelled in two different methods was demonstrated, one of which is using Lagrange equations and Finite Element Method to generate a mathematical model of the manipulator, and the other is creating a 3D model with the aid of Autodesk Inventor then import to MATLAB Simulink, both models were subsequently controlled by three types of controllers, conventional PID controller, LQR controller, and LQG controller. The research demonstrated …

Numerical Investigation Of Mesh-Based Enhancement Of Vapor Bubble Condensation, Omar Darwish Ali Alqadi Alhammadi

Theses

The aim of this work is to study the vapor bubble condensation process and the enhancement technique via affecting bubbles dynamic using a mesh-based structure. The bubble dynamics and thermal behavior are studied by considering the heat and mass transfer through the bubble’s interface area between the vapor and liquid regions and the resulting condensation effects. The thermal characteristics of bubbles are observed considering the initial and final liquid temperatures. Additionally, the bubble dynamics are studied in terms of several parameters including the relative velocity of the bubble, bubble deformation, interfacial area, and the bubble diameters. The relation between the …

Bending-Torsion Flutter Analysis Of A Viscoelastic Tapered Wing Carrying An Engine And Subjected To A Follower Thrust Force, Youssef Shaaban Abdelfattah Matter

Theses

Flutter, a dynamic divergent instability, is one of the significant phenomena of Aeroelasticity. This dangerous aeroelastic phenomenon can occur to any flexible structure subjected to aerodynamic forces such as aircraft wings, bridges, buildings, etc. It is important to analyze the flutter in order to predict the speed and frequency at which it occurs so that structural damages and failures can be avoided. This thesis is concerned with non-dimensional parametric modeling of the flutter of a viscoelastic tapered wing with an attached engine. The main objectives of this thesis are to determine regions of stability and boundaries of flutter speed and …

Development Of Piezoelectric Energy Harvesting System For Low-Frequency Vibrations, Mai Rabie Mahmoud Ismail

Theses

Harvesting energy from vibration sources has attracted the interest of researchers for the past three decades. Researchers have been working on the potential of achieving self-powered MEMS scale devices. Piezoelectric cantilever harvesters have caught the attention in this field because of the excellent combination of high-power density and compact structure. The main objective of this thesis is to develop a novel and optimum piezoelectric harvester system using lumped parameter model (LPM) for given vibration sources. The finite element model (FEM) is used in this work as an original approach to be utilized for optimal design optimization. Three types of validations …

Thermo Hydraulic Performance Of Polymer Double-Pipe Heat Exchanger For Single-Phase Heating/Cooling Application, Ahmed Mohamed Gafar

Theses

This thesis details the model-based study carried out for understanding the thermal and hydraulic performance of double pipe heat exchangers with and without pin-fins; both counter and parallel flow configurations are considered in the study. The pin-fins are located on the outer wall of the inner pipe thereby extending into the annulus and in this study, the hot fluid is assumed to pass through the annulus. The model consists of multiple governing equations such as continuity equations, Navier-Stokes equations, and energy equations. A fluent module of Ansys Workbench is used for conducting the model-based study. Double pipe heat exchangers constructed …

Material Handling System For An Advanced Flexible Manufacturing Environment, Con Cronin

Theses

A Flexible Manufacturing System (FMS) is a method of production that is designed to easily adapt to changes in the type and quantity of the product being manufactured. Machines and computerised systems can be configured to manufacture a variety of parts and to handle the changing levels of production that is required. The aim of this project was to investigate the current manufacturing processes of Kostal Ireland GmbH with the aim of developing a bespoke prototype material handling system to achieve flexible manufacturing. Kostal Ireland GmbH currently do not have the ability to change their manufacturing operations easily when a …

Cycloidal-Drive Joint Design For Wearable Exoskeletons, Abhi J. Rawal

Theses

This thesis's scope was to construct a highly back drivable and compact joint design that can be used for wearable exoskeletons specifically designed to assist with rehabilitation. A compact cycloidal gear transmission was designed to satisfy the compactness requirement while ensuring the minimum torque is required for backdriving the mechanism. The joint was designed based on the compact cycloidal drive specifications, and the backdrivability test was performed to measure the minimum torque required (1.20 Nm) to backdrive. The joint design incorporates various important features such as rotation lock feature to prevent hyperextension, a housing design that offers the benefit of …

Tomato Puree Convective Heat Transfer Simulation Using Boussinesq Approximation, Matteo Fabbri

Theses

With the advance of new technologies, the food industries are requiring systems that allow to produce the desired products with faster rates at cheaper costs. In this case, the study was initiated with the purpose to better understand what happens inside a package containing tomato puree when this is heated above 343 K in a tunnel pasteurizer. If the fluid must reach the thermal and microbiological condition of “pasteurization”, the system must guarantee that the temperature (around 343° Kelvin) is kept for a certain time allowing to pasteurize even the cooler package’s fluid-particle. The faster the system can heat the …

Mechanics Of Binder-Particle Interactions In Composite Battery Electrodes, Richard Johnson

Theses

A study into the particle level mechanics of polymer binder and active material used in composite lithium-ion batteries (LIB) has been conducted. Silicon is highly sought after material that can be used as an active material in a composite anode. Its high theoretical capacity can result in batteries that can store more energy than current LIBs, but high volume expansion of Si during charge/discharge cycles leads to rapid capacity fade and poor cyclic life. Understanding the stress that is generated in the binder and the active material due to the volume expansion has not been fully understood. In this study …

Mechanical Characterization And Fracture Behavior Of Magnesium Zk60a Alloy (Uns M16600), Mohamed Kamal I. H. Temraz

Theses

This research work focuses on studying the mechanical and fracture behavior of one of magnesium ZK60A (UNS M16600) extrusion. The material has many industrial applications and its characteristic should be measured for proper component or system design. Several tests were conducted following the standard procedures to determine the mechanical characteristics of the material. In addition, the fracture toughness of the material has been measured using the fracture toughness-thickness curve. A stress intensity factor K was used as a fracture parameter to determine the plane strain fracture toughness KIC of ZK60A magnesium alloy using a single edge notch bend (SENB) specimen …

Effect Of Turbostratic Orientations And Confined Fluid On Mechanical Strength Of Bi-Layer Graphene: A Molecular Dynamics Study, Nil B. Dhankecha

Theses

The rise of graphene as a reinforcement material in the last decade has been exponential owing to its superior mechanical properties. This one atom thick 2D material is applicable in many industries related to nanomechanical, nanoelectronics and optical devices. Despite its strength and superior properties, single-layer graphene tends to be unstable in a free-standing form. This led to active use of bi-layer and multilayered graphene in many of the above-stated applications. Though properties of single-layer graphene have been extensively investigated both computationally as well as experimentally for over a decade, bilayer graphene and its turbostratic form are still under research. …

Feedback Control For Leader Follower Architecture Of Unmanned Arial And Ground Vehicles, Mahmoud El Mahmoud

Theses

This thesis presents development of a feedback controller for a cooperative mission using unmanned aerial vehicle and unmanned ground vehicle. This developed controller offers a solution to the time delayed collaborative autonomous systems for multiple robot systems. There are many motivating applications for these missions including exploration, search and rescue in damaged areas. The architecture developed in this thesis consists of an unmanned ground vehicle as a leader and an unmanned aerial vehicle as a follower. To be specific, the unmanned ground vehicle navigates through a damaged environment and leads the mission. The unmanned aerial vehicle follows the leader and …

Design And Fabrication Of A Remote-Controlled Plane For The Advanced Class Sae Aero Design Competition, Simon Esau

Theses

The goal of the present research is to optimize the radio-controlled airplane design for the Society of Automotive Engineers International (SAE) Aero Design Advanced Class competition. The SAE Aero Design Advanced Class seeks to further research and development of an aeronautic system that can deliver cargo and passengers to form a colony on Mars. Mission success is achieved by attending to the rules, constraints, and requirements of the competition. System-level engineering is applied to meet these diverse requirements and create a robust final product. The radio-controlled airplane submitted for competition can theoretically be scaled to carry colonists, habitats, and supplies …

Mechanical Design Automation: A Case Study On Plastic Extrusion Die Tooling, Allen Prasad Varghese

Theses

The Skills Gap in Mechanical Engineering (ME) Design has been widening with the increasing number of baby boomers retiring (Silver Tsunami) and the lack of a new generation to acquire, practice and perfect their knowledge base. This growing problem has been addressed with several initiatives focused on attracting and retaining young talent; however, these types of initiatives may not be timely for this new group to be trained by an established Subject Matter Expert (SME) group. Automated Engineering Design provides a potential pathway to address not only the Skills Gap but also the transfer of information from SMEs to a …

Control Of Separated Flow Using A Dielectric Barrier Discharge Plasma Actuator, Mahdi Hasan

Theses

Historically, Dielectric Barrier Discharge (DBD) plasma actuators have shown to be an effective method to control adverse pressure gradient induced boundary layer separation. In this study, a numerical investigation was carried out to explore the effects of a DBD plasma actuator on a three-dimensional incompressible, separated flow. The well-validated National Aeronautics and Space Administration (NASA) wall-mounted hump configuration studied in the simulations, were run at a Reynolds Number of 936,000, based on chord length, and a freestream Mach number of 0.1. The baseline code, CALC-LES, developed by the Chalmers University of Technology was modified to include the effects of the …

Modelling Of Oxygen Diffusion In Cork, Swapnil Shivputra Rane

Theses

The primary objective of this project is to better understand gas diffusion through natural cork structures by comparing simulations of gas diffusion through natural cork to experimental measurements of oxygen gas diffusion through the same structure. The cork's internal structure is measured using x-ray computed tomography (CT). From the measured internal structure, a simple mapping is assumed converting the measured x-ray computed tomography images into a 3D map of local diffusion coefficient. Specifically, it is assured that the x-ray CT pixel value is inversely proportional to the diffusion coefficient of oxygen through the cork. A diffusion model for the cork …

Thermal And Structural Characterization Of Macro-Encapsulated Phase Change Material Integrated Into Concrete Cubes, Yasir Rashid

Theses

High-energy consumption in buildings is a research issue of great importance today, with solid-liquid phase change materials (PCMs) proving an excellent candidate for passive means to reduce energy consumption. In the current research, a novel protective coating was developed from geopolymer to encapsulate a PCM to prevent leakage in the liquidous phase. The PCM was characterized using a customized temperature history method (THM) and standard differential scanning calorimetry (DSC). Two different porous materials, polyurethane foam and lightweight expanded clay aggregate (LECA), were selected to hold the PCM and act as a matrix in which to develop PCM capsules. Ingredients of …

Predicting Energy And Water Consumption On Dairy Farms Through Statistical Analysis And Machine-Learning Methods, Philip Shine

Theses

With the abolishment of milking quotas across all European Union member states in April 2015, dairy farmers must adjust their farming practises to minimise milk production costs to adequately prepare for potential periods of reduced revenue. Milk production is an intense energy and water consuming process. Coupled with challenging European greenhouse gas reduction targets and legislation regarding the prevention of groundwater pollution and deterioration, increasing the production of milk in Ireland must be met with the sustainable consumption of on-farm energy and direct water resources, to ensure the future monetary and environmental sustainability of Ireland’s dairy industry. Thus, this body …

Development Of A Dynamic Cfd Model For Offshore Oscillating Water Columns With Non-Linear Interactions, Ken O'Connell

Theses

This thesis focuses on the development of a state of the art modelling technique for offshore Oscillating Water Column (OWC) type Wave Energy Converters (WEC) using Computational Fluid Dynamics (CFD). Current literature indicates a limited amount of work has been completed on studying these devices containing non-linear time dependent flow phenomenon. Initially, a 2D Numerical Wave Tank (NWT) is studied to reduce discretisation error in order to reproduce accurately propagating waves. Further development into a 3D domain permits the geometrical requirements of an OWC type spar buoy to be included.

In parallel, a single Degree of Freedom (DOF) model is …