Engineering Commons^™

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 …