Engineering Commons^™

Development Of Superior Energy Absorbing Devices With Adaptive Capabilities Utilizing Hybrid Cutting/Clamping Deformation Modes, John Magliaro

Electronic Theses and Dissertations

The primary objective of this research was to investigate cutting deformation modes, employing higher-bladed cutters (i.e. 6 or more evenly space blades), with an emphasis on superior energy absorbing capabilities in comparison to axial crushing, the current state-of-the-art. A series of test cases involving AA6061 extrusions were identified utilizing analytical models of the steady-state cutting force and mean crushing force and selecting geometries where the ratio of the former force normalized with respect to the latter exceeded unity. Quasi-static testing confirmed that the total energy absorbing capacity could be exceeded while simultaneously reducing the peak force under quasi-static loading for …

Predictive Model Of Air Dam Deflection Under Aerodynamic Loads, Chang Kyun Kang

Electronic Theses and Dissertations

Plastic components are widely used on the exterior body of automotive vehicles. When the vehicle is moving, these components experience deformation caused by air flow. Simultaneously, the deformation affects the flow of air around the vehicle. This research is focused on developing virtual simulation techniques for determining the vehicle air dam behaviour under aerodynamic loads. The main objective of this research is to develop a fluid-structure interaction (FSI) methodology for predicting deflection of the air dam.

Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) codes are coupled so that fluid pressure and air dam displacement parameters are exchanged. The …

Development Of Superior Energy Absorbing Devices With Adaptive Capabilities Utilizing Hybrid Cutting/Clamping Deformation Modes, John Magliaro

Electronic Theses and Dissertations

The primary objective of this research was to investigate cutting deformation modes, employing higher-bladed cutters (i.e. 6 or more evenly space blades), with an emphasis on superior energy absorbing capabilities in comparison to axial crushing, the current state-of-the-art. A series of test cases involving AA6061 extrusions were identified utilizing analytical models of the steady-state cutting force and mean crushing force and selecting geometries where the ratio of the former force normalized with respect to the latter exceeded unity. Quasi-static testing confirmed that the total energy absorbing capacity could be exceeded while simultaneously reducing the peak force under quasi-static loading for …

Quantification Of Velocity At The Sparkplug In A Lab Scale Combustion Chamber, Mayur Panduranga Kodikal

Electronic Theses and Dissertations

Lean burn has been considered an effective strategy to improve the thermal efficiency of spark-ignition engines. Under lean or diluted conditions, however, the combustion speed is reduced. Therefore, to speed up the combustion, in-cylinder turbulence is induced which may impede the spark initiation. This research aims to quantify the turbulence in a constant volume optical combustion chamber.

An Improved Delayed Detached Eddy Simulation (IDDES) study was done to understand the turbulence characteristics of the flow in the optical chamber. Spark anemometry was used to obtain a relationship between the spark plasma evolution and freestream velocity. Finally, this technique has been …

Development Of A Stochastic Reactor Model Network Towards Combustion Systems, Nupur Gupta

Electronic Theses and Dissertations

Due to their negative health implications, the reduction of emissions from combustion processes is imperative. In order to reduce emissions, predicting and understanding their thermo-chemical formation in different types of combustion systems are necessary. Modern combustion systems, such as internal combustion engines and gas turbine engines, require innovative numerical methodologies that aid in the understanding of underlying chemical kinetics and mixing time-scales, all while being computationally inexpensive. However, current inclusive methodologies for predicting emissions and ignition events rely on computationally expensive computational fluid dynamics. The main objective of this thesis is to present a newly developed stochastic reactor model network …

Finite Element Analysis Of Surface Hardening Treatments Of Steels For Automotive Powertrain Applications, Filippo Jones

Electronic Theses and Dissertations

Surface hardening is a procedure that is usually performed on steel components, in order to impart in these the strength and surface hardness that are necessary for their correct operation, whilst maintaining a reasonable value of ductility in the overall component.

The latter is usually composed of a sequence of heat treatments: carburizing, quenching and tempering. Each of these have different effects that, if correctly combined, can lead to the desired final mechanical properties in the component.

Carburizing is a process that increases the amount of carbon concentration at the component surface. Quenching is a quick decrease in temperature that …

Thermal Efficiency Analysis On Lean Burn Spark Ignition Engine, Joshua Patrick Jayaseelan

Electronic Theses and Dissertations

Advanced spark ignition (SI) engines can operate under lean conditions in order to improve the efficiency and reduce the emissions. Under extensive lean conditions, the ignition and complete combustion of the charge mixture is a challenge, because of the reduced cylinder charge reactivity, leading to combustion instabilities, thus making the empirical investigations in the vicinity of and beyond the lean limit of current engines, unviable. With further improvements to the ignition and combustion control, the lean operation limit may be extended in future engines. To circumvent this limitation to an extent, in this work, the potential of extremely lean mixtures …

Reaction Wheels Fault Isolation Onboard 3-Axis Controlled Satellite Using Enhanced Random Forest With Multidomain Features, Mofiyinoluwa Oluwatobi Folami

Electronic Theses and Dissertations

With the increasing number of satellite launches throughout the years, it is only natural that an interest in the safety and monitoring of these systems would increase as well. However, as a system becomes more complex it becomes difficult to generate a high-fidelity model that accurately describes all the system components. With such constraints using data-driven approaches becomes a more feasible option. One of the most commonly used actuators in spacecraft is known as the reaction wheel. If these reaction wheels are not maintained or monitored, it could result in mission failure and unwarranted costs. That is why fault detection …

Numerical Studies On Liquid Water Transport In Pemfc Cathode With Biomimetic Flow Field Designs, Duy-Khang Dang

Electronic Theses and Dissertations

The performance and durability of proton exchange membrane fuel cells (PEMFCs) are greatly influenced by their water management capability. Therefore, novel flow field designs have been developing by researchers for the improvement of PEMFCs. Among those designs, novel biomimetic designs or so-called nature-inspired designs have captured special attention from researchers due to their capability of distributing fluids effectively with their prominent characteristics such as low pressure drops and efficient fluid distribution. This thesis presents a numerical investigation of the liquid water transport in PEMFC cathode with various biomimetic flow field designs. It includes a symmetrical biomimetic flow field design based …

Optimization Of Chemical Compositions Of Al-Si-Cu-Ni-Sr Alloys With High Strengths And Electrical Conductivities, Yuxian Li

Electronic Theses and Dissertations

Mechanical strengths and electrical conductivity are the very important engineering properties of lightweight metallic materials used in the automotive industry, especially for battery-powered electric vehicles (BEV). However, the main issue is that high strength and high electrical conductivity are mutually exclusive due to physical nature of these properties. The aim of this study is to develop new cast aluminum alloys for the production of rotor bar in the rotor with high as-cast strength and electrical conductivity. A design of experiment (DOE) technique, Taguchi method, was used to develop high as-cast strength and electrical conductivity alloys with various element addition of …

A Data-Driven Approach Using Long-Short Term Memory For Fault Prognosis And Remaining Useful Life Estimation Of Satellite Reaction Wheel, Md Sirajul Islam

Electronic Theses and Dissertations

Artificial satellites are objects or a body that are stationed in the orbit of another object. The purpose of artificial satellites includes monitoring, information transfer, studying a different planet, space exploration, and fulfilling many other modern-day needs. For the increased demand, the number of artificial satellites revolving around the earth is also increasing. Due to cost efficiency, bulk manufacturing capability, and ease to launch in the orbits, small satellites are the topic of interest. Reaction wheels are widely used in the attitude control system of small satellites. Unfortunately, reaction wheels failure restricts the efficacy of a satellite, and it is …

The Impact Of High Voltage Electrode Diameter On Spark Discharge Process, Jiaming Zhang

Electronic Theses and Dissertations

The ever-growing demands to meet the exhaust emission regulations and fuel economy requirements, drive the development of modern spark ignition (SI) engines towards lean or diluted conditions at boosted intake pressure and with intensified charge motions. Boosted in-cylinder pressure conditions require additional energy to initiate the spark discharge, thereby challenging the ignition system. Additionally, the geometry of the spark plug has a profound influence on the spark discharge characteristics. The main objective of this research is to study the impact of high voltage electrode diameter on breakdown voltage and equivalent spark gap resistance at elevated background pressures (1-25 bar abs.). …

Development Of A Pneumatically Controllable Microdroplet Generator With Electrical Sensing, Gnanesh Nagesh

Electronic Theses and Dissertations

Microfluidic droplet generation is popular in lab-on-a-chip based biochemical analysis because it can provide precise and high throughput fluids in the form of small droplets. This thesis presents a T-junction microdroplet generator with pneumatic actuation for regulating droplet size and a capacitance-based sensor with real-time sensing capability for characterizing droplet composition and size. The multi-layer device developed in this thesis is compatible with rapid manufacturing using a desktop-based laser cutter to fabricate the fluidic and pneumatic layers. A finite element based numerical model was developed to predict the best operating and geometric parameters for droplet generation. It was revealed that …

Interfacial Heat Transfer In Squeeze Casting Of Cast Al Alloy A380 And Mg Alloy Az91 And Wrought Alloy Az31, Luyang Ren

Electronic Theses and Dissertations

The weight reduction of vehicles and airplanes in the automotive and aerospace industries is urgently needed due to the government regulation and market demand. To satisfy engineering performance of lightweight auto and aero components, high strength light alloys such as aluminum (Al) or magnesium (Mg) alloys are usually adopted. This study was intended to explore a solution for casting high strength cast and wrought Al and Mg alloys. Before light alloys can be utilized for mass production, critical processing parameters need to be accurately determined. The interfacial heat transfer coefficient is one of the most important factors in casting processes. …

Pseudo-Zero Velocity Re-Detection Double Threshold Zero-Velocity Update Method For Inertial Sensor-Based Pedestrian, Tianyi Zhao

Electronic Theses and Dissertations

Zero-velocity update method is widely used in inertial measurement unit based pedestrian navigation systems for mitigating sensor drifting error. In the basic pedestrian dead reckoning system, especially in a foot-tie PDR system, zero-velocity update method and a Kalman filter are two core algorithms. In the basic PDR system, ZUPT usually uses a single threshold to judge the gait of pedestrians. A single threshold, however, makes ZUPT unable to accurately judge the gait of pedestrians in different road conditions. In this thesis paper, we propose a new, redesigned zero-velocity update method without using additional equipment and filter algorithms to further improve …

Comparative Investigations From Tribological And Corrosion Properties Of Alumina And Nickel-Alumina Coatings On Cast Iron, Jiayi Sun

Electronic Theses and Dissertations

Plasma Electrolytic Aluminating (PEA) Alumina coating on cast iron has a high wear/ corrosion resistance, but porous structure could cause pitting corrosion. Nickel is a widely used anti-corrosion material, but the wear resistance of nickel could still be developed. To explore advantages and disadvantages of combination of these two materials, electroless Nickel plating was applied on PEA Alumina coating. Electroless plated Ni grew from the interface of the alumina coating and cast iron and then sealed the micropores of the alumina coating in a nickel acetate bath, which could protect cast iron substrate from the pitting corrosion. In addition, some …