Investigation of Mode I and Mode II fracture behavior of aluminum-FTP composite structures bonded with new generation liquid thermoplastic Elinium® resin

Fiber-reinforced thermoplastic composites have garnered significant attention across various industries due to their recyclability, reprocessability, and high strength-to-weight ratios. However, the high melt viscosity of thermoplastic polymer matrices and challenges in fiber impregnation limit their application areas. On the other hand, thermoplastic monomers like Elium® resin offer innovative solutions by enabling fiber impregnation at room temperature through methods such as vacuum infusion and resin transfer molding, with ongoing advancements in the development of Elium® matrix-based fiber-reinforced composites via various manufacturing techniques. Fully understanding the mechanical performance of Elium® matrix composites is crucial before their widespread use in industrial applications. This thesis investigates the fracture behavior of structures composed of Elium® matrix composites reinforced with glass, carbon, and basalt fibers combined with aluminum components. To evaluate the mechanical performance of these composite-aluminum structures, double cantilever beam (DCB) and end-notched flexure (ENF) tests, along with single lap joint tensile tests, were conducted. These tests assessed interlaminar crack propagation behavior under Mode-I and Mode-II conditions, the energy released during crack initiation and propagation, and interfacial mechanical performance, allowing comparisons among different reinforcement types. In particular, the single lap joint tensile tests revealed shear stresses and load-carrying capacities at the aluminum-composite interface. Additionally, fracture damage images of the composites were analyzed using microscopy and compared across samples. With its properties of low viscosity, thermoformability, and recyclability, Elium® resin emerges as a promising matrix material for innovative and sustainable composite systems. This study provides valuable insights into the fracture mechanics of Elium® matrix composites and aims to enhance their suitability for damage-resistant applications. The findings contribute to the development of sustainable composite materials, supporting the industrial adoption of high-performance, recyclable composites.