Engineering Commons^™

Head Impact Effects In Small Remotely Piloted Aircraft System (Srpas) Collisions: Gender Specific Risks And Vulnerable Population Protection, Md Farhan Hoque Sagar

Electronic Thesis and Dissertation Repository

This study focuses on supporting the development of safety regulations for vulnerable populations during drone to head impacts. First, the small female head and neck model was compared to cadaveric data. Then, combined with lab’s previous work, gender-based disparities in head impact responses were highlighted, with small females experiencing higher injury risk metrics, despite lower skull von Mises stress. Beyond small females, children of various ages and their head responses during impacts were also analyzed. In addition to the previously developed quadcopter drone model, a new Mavic Pro drone model was developed, and this model was integrated with human head …

Experimental And Simulation Study Of Reactive Silver Ink Droplet Evaporation, Weipeng Zhang

Electronic Thesis and Dissertation Repository

The evaporation of particle-free silver ink droplets on heated substrates directly impacts the morphology of the resultant silver particles and films. In this thesis, COMSOL Multiphysics simulations of the solvent (water-ethylene glycol mixture) droplet evaporation process are used to explain the microflows, mass transfers, and heat distribution responsible for the experimental observations. The reactive ink incorporates fluoro-surfactant FS-31 and poly (acrylamide) (PAM) to suppress the coffee-ring effect that negatively impacts the electrical conductivity. Experiments show that the droplet evaporation process results in varied silver particle morphology, depending on the locations within the droplet, leading to uneven surfaces. Large particles (3 …

Numerical Modeling And Simulation On Deformation And Failure Behaviors Of Polymeric Materials, Heng Feng

Electronic Thesis and Dissertation Repository

Featured by biocompatibility, high compliance and capacity in sustaining large deformation, dielectric elastomers (DEs) and hydrogels have gained extensive research popularity for their potential applications in the fields of soft robots, biomimetics, tissue engineering, drug delivery, and energy harvesting. The design of such soft and smart material-based devices and structures requires deep understanding and accurate simulation of their constitutive behaviors, which is challenged by their nonlinear material properties due to unique microstructures and multi-physics coupling. Meanwhile, in different application contexts, those structures are also susceptible to different failure modes, imposing further challenges in simulating and predicting their performance. To fulfill …

Effect Of Ion Irradiation On The Rate Dependence Of Plastic Deformation Of Extruded Zr-2.5%Nb, Konrad P. Mazurkiewicz

Electronic Thesis and Dissertation Repository

The purpose of this thesis is to examine the properties of Zr-2.5%Nb pressure tube material in the transverse direction. Through testing at room temperature, material properties such as the strain hardening, strain rate sensitivity and apparent activation volume were investigated. The effects of Zr⁺ ion-implantation occurring at 300°C, simulating irradiation-induced damage, and the strain rate of loading on these properties were also investigated.

Two methods of testing were performed: in-situ micro-pillar compressions and nanoindentation testing. Ion-implantation was observed to increase material strength and hardness. However, certain implanted micro-pillars displayed early localized failure that reduced strength. This finding warrants further …

Use Of Electrochemical Techniques And Statistical Analysis To Investigate The Pitting Probability Of Copper, Sina Matin

Electronic Thesis and Dissertation Repository

The development of a safe permanent disposal plan is essential for the long-term disposal of used fuel bundles. Nuclear Waste Management Organization (NWMO) has been investigating the deep geologic disposal of nuclear waste which offers the optimum passive safety system with a negligible probability of release of radionuclides into the environment.

The proposed used fuel containers (UFC) for the permanent disposal of high-level nuclear waste in Canada is comprised of a carbon steel vessel coated with a 3 mm corrosion-resistant copper layer deposited using a combination of electrodeposition and cold spray deposition. Although copper is often considered to be thermodynamically …

Development Of Pulsed Laser Deposited Tio2, Zno And Azo Thin Uv-Protection Films For Enhanced Perovskite Photostability, Kate Lochhead

Electronic Thesis and Dissertation Repository

Perovskite solar cells are an emerging sustainable energy conversion technology with the potential to provide relief from the global energy crisis. However, the UV-induced degradation of perovskites has been a barrier to commercialization. Thin film encapsulation represents a promising solution for extending device lifetimes. Three materials with suitable bandgaps for blocking UV light are identified: TiO₂, ZnO and AZO. Herein, the optical properties of TiO₂, ZnO and AZO thin films grown by room-temperature pulsed laser deposition are optimized by varying the oxygen partial pressure during deposition. UV-Vis spectroscopy reveals facile bandgap tuning via the concentration of …

Mechanical Property Of Body-Thoroughly Enhanced Austenitic Stainless Steel And High-Mn Steel By Industry-Applicable 3-Axis Stress-Released Impact, Busheng Zhang

Electronic Thesis and Dissertation Repository

As two important austenitic steels, the austenitic stainless steel (SS) and austenitic high-Mn steel have been seeking a decent yield strength to match their versatile exceptional advantages. However, the traditional, severe, and high-strain-rate plastic deformation techniques currently used to strengthen the austenitic steels, are limited by their ability to produce ultrastrong steel, bulk sized steel, and the fracturing risk they pose to the steel, respectively. In this research, we propose an industry-applicable 3-axis stress-released impact process, which addresses the challenges facing the current techniques and successfully prepares the body-thorough ultrastrong and ductile austenitic steels without fracturing risk.

The bulk 316L …

Enhanced Performance Of 3d Electroactive Polymer Transducers Via Hierarchical Structures, Frederick B. Holness

Electronic Thesis and Dissertation Repository

Conjugated polymers (CPs) are a class of polymers that exhibit a change in size or shape in response to electrical stimuli. The unique combination of electrical and mechanical properties facilitates the fabrication of novel devices in a broad range of applications including: sensors, actuators, and lab-on-a-chip systems. The alternating single and double bonds along the polymer chain of CPs enables their electroactive properties but is also responsible for processability associated with CPs that has limited fabrication methods. Recently a photosensitive CP composite enabling additive manufacturing (AM) of 3D CP structures was developed. However, the introduction of a copolymer for mechanical …

Near-Ir Laser Ablation Of Simulated Radiologically Contaminated Oxides On Carbon Steel Feeder Pipes, Thao Viet Do

Electronic Thesis and Dissertation Repository

As nuclear power plants age and retire from service, many countries face significant challenges concerning the safe long-term storage and disposal of large volumes of low and intermediate level radioactive wastes (L&ILW). The volumes of metallic waste are of particular concern, as when metal corrodes it produces hydrogen that could lead to pressure build-up in interim storage and disposal. In Canada, a significant fraction of the metallic wastes for Canada Deuterium Uranium (CANDU) nuclear reactors are out-of-core reactor components, such as carbon steel (CS) feeder pipes. The radioactive contamination is expected to be largely confined to the surface oxide layers …

Damage In Non-Crimp Fabric Carbon Fiber Reinforced Epoxy Composites Under Various Mechanical Loading Conditions, Aaditya Pradeep Suratkar

Electronic Thesis and Dissertation Repository

Composite materials have emerged in the recent years as a frontrunning lightweight replacement for metals for structural applications in lightweight automobiles. However, the key adoption criteria for composites in lightweight vehicles is their crashworthiness, i.e., the amount of energy a structure made with composites would absorb in a crash event. The energy is absorbed in composites through various damage modes such as matrix cracks, delamination, fiber breakage, etc. Therefore, adoption of a certain composite material system requires thorough understanding of the initiation and propagation of damage until failure in that system under various mechanical loading conditions, which is also the …

Hydration Kinetics, Microstructure, And Mechanical Strength Development Of Cement-Based Composites Incorporating Phase Change Materials, Afshin Marani

Electronic Thesis and Dissertation Repository

The research conducted in this thesis investigates the effects of phase change materials (PCMs) on the hydration kinetics and strength development of cement-based composites using extensive experimental and numerical analyses. Purposefully, the effect of microencapsulated PCMs (MPCMs) on the strength development of cement-based mortars and concretes was evaluated using powerful machine learning models trained with the largest available experimental data. Furthermore, a novel ternary machine learning approach was proposed to optimize the mixture design of mortars and concretes based on the thermos-physical properties of the MPCMs. The results obtained from machine learning simulations suggest the assessment of the effects of …

On The Effects Of Additive Manufacturing Process Parameters On The Performance Of Hastelloy-X: A Neutron Diffraction Experiment And Crystal Plasticity Finite Element Model, Ahmed Aburakhia

Electronic Thesis and Dissertation Repository

Additive manufacturing (AM) is increasingly becoming one of the favourable manufacturing techniques in various industries, such as transportation and energy. The reason for the extensive use of AM lies in the ability to use a wide range of process parameters for manufacturing engineering parts with complex geometries that cannot be effectively manufactured using traditional methods such as casting or forging. Understanding the role of process parameters is crucial for developing predictive models, as well as for manufacturing engineering components with the desired properties.

This research aims to characterize the influence of AM process parameters on the deformation mechanisms of Hastelloy-X, …

Development Of High Performance Cathodes: From Liquid To Solid-State Batteries, Sixu Deng

Electronic Thesis and Dissertation Repository

Lithium-ion batteries (LIBs) are critical for the development of electric vehicles (EVs) because of their higher operating voltages compared to other energy storage technologies. However, the development of start-of-the-art LIBs touched the ceiling because of three main challenges: safety risks, limited energy density, and high cost. Accordingly, all-solid-state lithium-ion batteries (ASSLIBs) have recently emerged as promising alternative batteries for next-generation EVs because of their ability to overcome the drawbacks of conventional LIBs. Whether in conventional liquid LIBs or ASSLIBs, cathode materials are crucial in determining the overall performance. Hence, this thesis focuses on understanding the degradation mechanism of cathode interfaces …

Sol-Gel Derived Bioceramic Poly(Diethyl Fumarate – Co – Triethoxyvinylsilane) Composite, Aref Sleiman

Electronic Thesis and Dissertation Repository

Synthetic bone graft materials have become an increasingly popular choice for bone augmentation. Ceramic-based and polymer-based bone graft materials constitute the two main classes of synthetic bone graft materials. This study investigated the synthesis of novel bioactive composites for their potential use as bone graft biomaterials. Poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic class II organic/inorganic hybrid biomaterials were synthesized via a sol gel process. These biomaterials were then reacted with an ammonium phosphate solution to prepare their respective composites. For the first time, we successfully synthesized sol-gel derived bioceramic poly(diethyl fumarate-co-triethoxyvinylsilane) composites. In vitro bioactivity evaluation of poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic composites in simulated body fluid …

Material Characterization Of Compression Molded Composites, Broderic Clement-Thorne

Electronic Thesis and Dissertation Repository

Composite materials are widely used in the automotive industry to keep cost and weight down. The ability to simulate the fabrication of parts is an important way to use resources effectively. The molding process can also have very dramatic effects on material properties. These properties are determined by the microstructure of the polymer composite material, including the length, concentration, and orientation of the fibers used as reinforcement. Therefore this study seeks to characterize the material properties of a long glass fiber reinforced polyamide composite, the effects of molding conditions on those material properties, and characterization of the microstructure of the …

Composite Compression Co-Moulding: A Warpage Reduction Investigation, David Knezevic

Electronic Thesis and Dissertation Repository

To accommodate the increasing need for vehicle emission reduction, automotive manufacturers are presently looking at the next generation of lightweight materials. Glass fibre-reinforced thermoplastic composites belong to this group and exhibit mechanical properties that resemble traditional metals but at a reduced weight and with improvements on other characteristics. Unfortunately, they are affected by processing-related warpage, especially when fabricated by means of the Long Fibre-reinforced Thermoplastics – Direct (LFT-D) manufacturing process, a technology that is valuable because of its high throughput and flow lengths. This occurs for many reasons but reinforcing LFT-D with Glass Mat Thermoplastics (GMT) – another material format …

Characterization Of Material For Composite Automotive Components, Thomas J. Chang

Electronic Thesis and Dissertation Repository

A composite had been widely used for the lightweighting purpose amid increasing environmental concerns. Among composite manufacturing processes, compression molding is widely used for automotive parts. During compression molding, the mold geometry and molding process conditions significantly influence the fiber configuration and the mechanical performance.

Hence, this thesis aims to characterize the microstructural and mechanical properties of the complex shaped composite automotive components: outer seatback and inner seatback. Both parts were compression molded using commercial glass mat thermoplastic sheet with long glass fibers (30mm-50mm) embedded in the polyamide resin. The microstructural characterization results showed that the microstructural properties are influenced …

Development Of Advanced Solid-State Electrolytes And Interfaces For High-Performance Sulfide-Based All-Solid-State Lithium Batteries, Feipeng Zhao

Electronic Thesis and Dissertation Repository

All-solid-state lithium batteries (ASSLBs) have become increasingly attractive due to the demand of high-energy-density and high-safety lithium-ion batteries for electric vehicles (EVs). As the core component of ASSLBs, solid-state electrolytes (SSEs) are regarded as essential to determine the electrochemical performance of ASSLBs. The inorganic SSEs is one of the most important categories in all developed SSEs, representing the advance of superionic lithium conductors as well as the cornerstone to construct flexible polymer/inorganic composite SSEs. The sulfide-based inorganic SSE is one of the most promising SSEs that is receiving a lot of attentions, because only sulfide SSEs can show ultrahigh ionic …

Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications, William Anderson

Electronic Thesis and Dissertation Repository

Due to sensor size and supporting circuitry, in vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this thesis is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in biomechanical applications. The capacitive transducer membrane of the FXTH87 was modified, and a relationship was reported between applied compressive deformation and sensor signal value. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. Finite element analysis was an effective tool to …

Material Property Characterization For Elastomers Within The Framework Of Finite-Deformation Viscoelasticity, Shan Gao

Electronic Thesis and Dissertation Repository

Elastomers are polymeric materials that consist of highly mobile long-molecule chains jointed together through crosslinking. The behavior of elastomers is commonly manifested by hyperelasticity and viscosity due to their molecular structure. Any variation of the material microstructure may have an impact on the macroscopic properties of elastomers. Therefore, characterizing the material properties of elastomers with appropriate constitutive models is essential to facilitating their potential applications. Although various constitutive models have been developed to describe the hyperelastic and viscoelastic behaviors of elastomers, it is still challenging to quantify the material properties of elastomers since there exist restrictions and limitations of the …

Discontinuous Fiber Vacuum Assisted Compression Molding, Bennet Heidenreich

Electronic Thesis and Dissertation Repository

Discontinuous short fiber carbon reinforced polymer (CFRP) composites were manufactured, and tested to demonstrate feasibility, and to document material properties. Different variations of manufacturing techniques were tested including continuous fiber reinforcement, metal inserts, and randomization of the dry fibers before processing. The process produced parts with strength to weight ratios similar to 6061-T6 aluminum without continuous fiber reinforcement, and 53% higher when small volumes of continuous reinforcement are added. Randomization of fibers produced no significant change in strength of the material, but did increase compression stiffness of the mixture while molding, increasing tool deflection. A pin joint was tested, and …

Non-Linear Effects Of Solution Parameters And Gamma Radiation On Nickel Oxidation Dynamics, Razieh Karimihaghighi

Electronic Thesis and Dissertation Repository

Nickel is the main component in nickel-based superalloys which are known for their superior corrosion resistance and mechanical properties. These alloys are used in nuclear power plants, mainly for thin-walled heat exchanger tubing where these materials are exposed to a continuous flux of ionizing radiation. The long-term corrosion behaviour of these alloys at high temperatures and in the presence of gamma-radiation is not well understood. Moreover, the mechanism by which nickel improves the corrosion resistance of these alloys is also not known. Therefore, a mechanistic understanding of the nickel oxidation process is required to develop a predictive corrosion model for …

Study Of Recyclable And Repairable Dynamic Covalent Polymers For Sustainable 3d Printing Development, Mingyue Zheng

Electronic Thesis and Dissertation Repository

3D printing technology with valuable features, including cost-saving, easy access, and unlimited structure design, has attracted significant attention and been employed for production use. This technology has also been considered as a sustainable manufacturing method and quickly developed in recent years. However, the development of sustainable 3D printing is still facing challenges, especially in waste management. Thanks to the flexibility of 3D printing and diversified printing mechanisms, the big step forward can be approachable by the transformation from materials. This dissertation presents a variety of strategies designed for sustainable 3D printing development based on the combination of dynamic covalent chemistry …

Characterization Of The Mechanical Performance Of The Ae44-2 And Ae44-4 High Pressure Die Cast Mg-Rare Earth Alloys, Bolin Fu

Electronic Thesis and Dissertation Repository

This thesis aims to study the local mechanical properties of high pressure die cast (HPDC) AE44-2 and AE44-4 alloys at 25˚C and 200˚C and their microstructures. The chemical composition of the precipitates and grain size, the effect of cooling rate on the grains, the relationship between the grain size and mechanical properties, and the creep resistance of these two HPDC alloys were studied and discussed.

In this thesis, the spherical micro-indentation, constant Berkovich indentation tests, and tensile tests were performed on the specimens at 25˚C and 200˚C to probe their stress-strain response and creep behavior. This study used a new …

Development Of Water-Soluble Polyesters For Tissue Engineering Applications, Trent Gordon

Electronic Thesis and Dissertation Repository

The development of tunable polymers has become increasingly important for both tissue engineering and drug delivery. This thesis investigates the development of water-soluble polyesters that contain both natural and synthetic components. These polymers offer tunable chemical structures, as well as functional groups for the conjugation of crosslinking moieties or cell signaling molecules. The first series of polymers was synthesized from poly(ethylene glycol) (PEG) and aspartic acid (Asp) via a titanium catalyzed transesterification method to provide polymers with molar masses of 12 kg/mol. After deprotection, the pendent functional groups of Asp were reacted with methacrylic, maleic, and itaconic anhydride to introduce …

Evaluation Of Warpage For Composite Automotive Components, Eric J. Martin

Electronic Thesis and Dissertation Repository

Thermoplastic composite parts are manufactured using compression molding for the purposes of assembly in a car seat sub-assembly. Concerns about the dimensional accuracy of the parts prompted an investigation into the part warpage. The warpage of the parts needs to be evaluated for the purposes of determining processing conditions which are linked to part warpage, in order to reduce part warpage.

Laser line probes (LLP) are becoming a more attractive tool for the purposes of part inspection. LLPs quickly acquire point cloud data from complex surfaces and are a non-contact method of measurement; these qualities make LLPs the best tool …

Material Properties And Heat Transfer Parameters In Compression Molding Of Glass Mat Thermoplastics, Cheng Xu

Electronic Thesis and Dissertation Repository

The compression molding of glass mat thermoplastics (GMT) allows high volume manufacture of composite parts with a short production cycle. Computer simulation is often used to assist process development and optimization. Reliable simulation depends on input of material property parameters and accurate prediction of heat transfer. This thesis developed experimental methods to characterize material property and heat transfer process parameters. Results were obtained by applying the methods to a selected commercial GMT sheet. Heat transfer coefficients including convection coefficients during pre-heating and transfer, as well as contact conductance at sheet-mold interface were estimated by a parameter-fitting approach. Viscoelastic parameters of …

Machine Learning Prediction Of Mechanical And Durability Properties Of Recycled Aggregates Concrete, Itzel Rosalia Nunez Vargas

Electronic Thesis and Dissertation Repository

Whilst recycled aggregate (RA) can alleviate the environmental footprint of concrete production and the landfilling of colossal amounts of demolition waste, there need for robust predictive tools for its effects on mechanical and durability properties. In this thesis, state-of-the-art machine learning (ML) models were deployed to predict properties of recycled aggregate concrete (RAC). A systematic review was performed to analyze pertinent ML techniques previously applied in the concrete technology field. Accordingly, three different ML methods were selected to determine the compressive strength of RAC and perform mixture proportioning optimization. Furthermore, a gradient boosting regression tree was used to study the …

Measurement And Modeling Of Micro Residual Stresses In Pure Zirconium And Zr-2.5nb Polycrystals, Abdulla Alawadi

Electronic Thesis and Dissertation Repository

In CANada Deterium Uranium (CANDU) nuclear reactors, Zr-2.5Nb alloy pressure tubes separate the hot water and cold moderator. Pressure tubes are susceptible to the diffusion of hydrogen from water and formation of a brittle phase called zirconium hydrides. The diffusion and formation of hydrides are affected by the state of stresses within the tubes. As such, it is of great significance to understand the source of the stresses that develop within the tubes. This thesis focuses on the characterization of the micro and nano scale residual stresses that develop in pure zirconium and Zr-2.5Nb polycrystals. With using three-dimensional synchrotron X-ray …

Electronic And Local Structures Of Pt-Based Bimetallic Alloy And Core-Shell Systems, Jiatang Chen

Electronic Thesis and Dissertation Repository

This thesis investigates the electronic structure of Pt for catalysis applications. The importance of the Pt 5d band is discussed in terms of the bonding capability of Pt. The oxygen reduction reaction in proton exchange membrane fuel cells is chosen as the catalytic reaction model to illustrate the effect of Pt 5d states on Pt-O interaction. Pt-based bimetallic systems are introduced as a solution for the high price and limited resources of Pt. Despite lower usage of Pt, the tuning capability to optimize the Pt 5d band in bimetallic catalysts is supposed to provide superior catalytic activity. Advanced synchrotron X-ray …