Abstract
The escalating challenges of global climate change have accelerated a paradigm shift toward the use of lightweight materials in automotive applications as a strategy to reduce energy consumption and mitigate greenhouse gas emissions. Effective lightweighting not only requires mass reduction but also ensures safety, performance, energy efficiency, cost-effectiveness, and environmental sustainability. Achieving these demands calls for an integrated approach that combines advanced material utilization, recycled resources incorporation, and innovative structural design. Advanced materials such as metal alloys and carbon-based polymer composites offer promising solutions for weight reduction while maintaining high performance. The use of recycled materials provides environmental and economic advantages by converting waste into valuable resources. Optimizing their structural design enables efficient material redistribution, minimizing usage without compromising properties and structural integrity. However, the successful implementation of these material systems requires a deeper understanding of process-structure-property relationships to further enhance material functionality.
The aim of this dissertation is to explore the influence of materials distribution on the properties and structural integrity of metal alloy and polymer composites by integrating physical experiments, theoretical models, and three-dimensional numerical simulations. In the case of metal alloys, the focus is on understanding the effects of powder particle size and powder layer thickness on the laser beam attenuation and melt pool characteristics in Inconel 718 during the laser powder bed fusion process. A multi-pronged methodology combining physical and virtual experiments is employed to capture these phenomena and provide fundamental insights into the complex interaction between the high-intensity beam and the powder array. Optimizing powder distribution enables more effective control of the process conditions and melt pool behavior for enhancing productivity, reducing energy consumption, and lowering overall processing costs.
For polymer composites, the work explores the dispersion and structural arrangement of carbon-based fillers and nanofillers including carbon fibers, graphene, and carbon nanotubes within thermoplastic matrices such as ultra-high molecular weight polyethylene and polyamide matrices. These studies aim to improve multifunctional performance, including mechanical, thermal, electrical, and electromagnetic interference shielding properties, while clarifying the role of structural configurations in governing overall functionality. To promote sustainability, composite fabricated with recycled materials are explored as a pathway to achieve high-performance while reducing cost, energy consumption, and environmental impact. The integration of recycled constituents further highlights how filler distribution and layered architecture can be leveraged to design lightweight, high-performance materials with a reduced carbon footprint.
The underlaying mechanisms governing these behaviors are examined through combined physical characterizations and virtual simulations. Through these investigations, this dissertation advances the development of sustainable, cost-effective, and high-performance materials for automotive applications. The findings offer valuable insights into the trade-offs between material properties, processing techniques, and functional performance, contributing to the design of next generation lightweight, energy-efficient, and environmentally responsible materials. Recommendations for further work are offered in the final chapter of this dissertation.
