Structural Materials Commons^™

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 …

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 …

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 …

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 …

Rational Design Of Cell Configurations For High-Performance Na-O2 Batteries, Xiaoting Lin

Electronic Thesis and Dissertation Repository

Na-O₂ batteries are considered as the promising candidates for electric vehicles due to their ultrahigh theoretical energy densities. However, state-of-the-art Na-O₂ batteries suffer from serious challenges including 1) pore clogging and insufficient O₂ transportation within the air electrode; 2) degradation of air electrode, 3) Na dendrite growth; and 4) Na corrosion induced by O₂/O₂^- crossover. This thesis, therefore, focuses on rational design of cell configurations to address these problems and understanding the insight mechanisms.

3D printing of “O₂ breathable” air electrodes for Na-O₂ batteries were first developed. The unique air electrode …

Effect Of Ion Implantation On The Mechanical Properties Of The Grain And Grain Boundary Regions Of Inconel X750, Maisaa Nezar Tawfeeq

Electronic Thesis and Dissertation Repository

Annulus gas spacers in CANada Deuterium Uranium (CANDU) nuclear reactors are made from the heat-treated Inconel X750 Nickel-based alloy. This alloy is designed to have high strength and creep resistance at elevated temperature. Unlike other reactor designs, the CANDU reactor has a high thermal neutron fluence, which results in an enhancement of the radiation damage and the internal production of helium and hydrogen. They are thus susceptible to microstructural instability and mechanical property degradation with time. Studies of ex-service spacers have indicated that they display intergranular embrittlement and lower ultimate tensile strength compared to nonirradiated Inconel X750. The primary degradation …

Enhanced Carbon Fiber-Epoxy Composites For Rowing Racing Shells, Rayehe Samimi

Electronic Thesis and Dissertation Repository

This thesis investigates the thermomechanical properties of two commercial composites using carbon fiber reinforcement in epoxy resins for manufacturing marine based rowing racing shells. The main goal of this project was to investigate how to control the resin properties and curing temperatures to improve the final product properties including adhesion, toughness modulus and tensile strength. Moreover, an efficient curing process was required by our supporting company to be used at low temperatures to enhance the curing characteristics and to provide improved mechanical properties. Accordingly, the current research tries to improve the manufacturing curing process and build up high performance structure …

3d Printing Of Functional Materials: Surface Technology And Structural Optimization, Dongxing Zhang

Electronic Thesis and Dissertation Repository

There has been a surge in interest of 3D printing technology in the recent 5 years with respect to the equipment and materials, because this technology allows one to create sophisticated and customized parts in a manner that is more efficient regarding both material and time consumption. However, 3D printing has not yet become a mainstream technology within the established manufacturing routes. One primary factor accounting for this slow progress is the lack of a broad variety of 3D printable materials, resulting in limited functions of 3D printed parts.

To bridge this gap, I present an integrated strategy to fabricate …

In Mold Flow Of Long Fibers In Compression Molding Process, Gleb Meirson

Electronic Thesis and Dissertation Repository

Long Fiber Thermoplastics (LFT) are promising new materials with high physical properties and low density. These high properties are obtained by embedding very long fibers (~100 mm) into a thermoplastic matrix. Such a high fiber length dictates the use of a compression molding process for manufacturing as the length of discontinuous fibers in injection molding is limited by pellet length.

LFT composites are of great interest for the automotive industry. These materials are already used in some interior and exterior car parts such as bumpers, seat structures, door module etc. This research is inspired by the desire to manufacture load …

Numerical Studies For Improving Fracture Toughness Resistance Curve Testing Using Single-Edge (Notched) Tension Specimens, Yifan Huang

Electronic Thesis and Dissertation Repository

The fracture toughness resistance curve, i.e. the J-integral resistance curve (J-R curve) or the crack tip opening displacement resistance (CTOD-R) curves, is widely used in the integrity assessment and strain-based design of energy pipelines with respect to planar defects (i.e. cracks). This thesis deals with issues related to the experimental determination of the J(CTOD)-R curves using the newly-developed single-edge (notched) tension (SE(T)) specimens. In the first study, the plastic geometry factor, i.e. the η_pl factor, used to evaluate J in a J-R curve test based on …

Application Of Treated Oil Sands Drill Cuttings Waste In Micropiles Construction, Moustafa Ahmed Raafat Mohamed Aboutabikh

Electronic Thesis and Dissertation Repository

A micropile is constructed by drilling a hole, placing a steel reinforcing element, grouting it using neat cement. However, cement production consumes energy and generates carbon dioxide. Implementing waste materials in construction applications represents a sustainable solution for many waste management problems. On the other hand, oil sands drill cuttings waste represents one of the most difficult challenges for the oil sands mining sector. Reducing the amount oil sands drill cutting waste sent to landfill offers one of the best solutions for waste management. This thesis presents an innovative solution for application of treated oil sands waste (TOSW) in grout …

Application Of 3d Printing Technology In Porous Anode Fabrication For Enhanced Power Output Of Microbial Fuel Cells, Bin Bian

Electronic Thesis and Dissertation Repository

Microbial fuel cells (MFCs) are widely researched for application in wastewater treatment. However, the current anodes used in MFCs often suffer from high fabrication cost and uncontrollable pore sizes. In this thesis, three-dimensional printing technique was utilized to fabricate anodes with different micro pore sizes for MFCs. Copper coating and carbonization were applied to the printed polymer anodes to increase the conductivity and specific surface area. Voltages of MFCs with various anodes were measured as well as other electrochemical tests such as linear sweep voltammetry and electrochemical impedance spectroscopy. 3D copper porous anode produced higher maximum voltages and power densities …

The Effect Of Cutting Blade Geometry And Material On Carbon Fiber Severing As Used In High-Volume Production Of Composites, Michael Francis Anthony Adamovsky

Electronic Thesis and Dissertation Repository

Automotive manufacturers have started to actively look into weight savings options for mass production of vehicles that meet new government regulations. Falling prices of carbon fibers have made carbon fiber composites a promising material to be used. The study has focused on the fiber-severing unit incorporated in a high-volume composite production line in an attempt to better define the impact of blade geometry and material on the wear as experienced while cutting carbon fiber. A method to quantify the effect of usage on the cutting ability of a blade has been developed, as well as methods to measure blade wear. …

Production And Applications Of Formaldehyde-Free Phenolic Resins Using 5-Hydroxymethylfurfural Derived From Glucose In-Situ, Yongsheng Zhang

Electronic Thesis and Dissertation Repository

The phenol-formaldehyde (PF) resin manufacturing industry is facing a growing challenge with respect to concerns over human health, due to the use of carcinogenic formaldehyde and sustainability due to the use of petroleum-based phenol in PF resin manufacture. Glucose and its derivative, 5-hydroxymethylfurfural (5-HMF), have proven to be potential substitutes for formaldehyde in the synthesis of phenolic novolac resins.

This thesis investigated a number of glucose and 5-HMF resin systems including the curing of phenol-glucose novolac resin (PG) with a bis-phenol-A type epoxy. The curing process was modeled according to the Sestak-Berggren equation (S, B) using Málek methods. This was …

Mechanistic Failure Criterion For Unidirectional And Random Fibre Polymer Composites, Jamaloddin Jamali

Electronic Thesis and Dissertation Repository

Polymer composite design in energy absorbing components requires a failure criterion that can predict the energy involved in its fracture under different modes of loading. Present mixed mode criteria are mainly empirical or semi-empirical, and are only suitable for a small range of composite types.

The purpose of this study was to develop a mechanistic failure criterion that is applicable to a wide range of polymer composites. An energy based mechanistic failure criterion is proposed to characterize the toughness of unidirectional (UD) and randomly oriented short fibre composites (random fibre composites).

In UD and random composites, the criterion predicts the …

Finite Element Analyses Of Single-Edge Bend Specimens For J-R Curve Development, Yifan Huang

Electronic Thesis and Dissertation Repository

The fracture toughness resistance curve such as the J-integral resistance curve (J-R curve) is widely used in the integrity assessment and strain-based design of energy pipelines with respect to planar defects (i.e. cracks). Two studies about the development of the J-R curve are carried out and reported in this thesis. In the first study, the plastic geometry factor, i.e. the η_pl factor, used to evaluate J in a J-R curve test based on the single-edge bend (SE(B)) specimen is developed based on the three-dimensional (3D) finite element analysis (FEA). The main …

Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad

Electronic Thesis and Dissertation Repository

A formulation used to simulate the solidification process of magnesium alloys is developed based upon the volume averaged finite volume method on unstructured collocated grids. To derive equations, a non-zero volume fraction gradient has been considered and resulting additional terms are well reasoned. For discretization the most modern approximations for gradient and hessians are used and novelties outlined. Structure-properties correlations are incorporated into the in-house code and the proposed formulation is tested for a wedge-shaped magnesium alloy casting. While the results of this study show a good agreement with the experimental data, it was concluded that a better understanding of …

Early-Age Shrinkage Of Ultra High-Performance Concrete: Mitigation And Compensating Mechanisms, Ahmed Mohammed Soliman

Electronic Thesis and Dissertation Repository

The very high mechanical strength and enhanced durability of ultra high-performance concrete (UHPC) make it a strong contender for several concrete applications. However, UHPC has a very low water-to-cement ratio, which increases its tendency to undergo early-age shrinkage cracking with a risk of decreasing its long-term durability. To reduce the magnitude of early-age shrinkage and cracking potential, several mitigation strategies have been proposed including the use of shrinkage reducing admixtures, internal curing methods (e.g. superabsorbent polymers), expansive cements and extended moist curing durations. To appropriately utilize these strategies, it is important to have a complete understanding of the driving forces …