The future of aerostructures relies heavily on advances in materials and structures in view of affordability, safety, and environmental compatibility. Reinforced polymer composite materials have shown tremendous promise over the past few decades for use in lightweight aircraft structures due to their high strength-to-weight ratios, which results in significant energy savings. However, these structures are often exposed to multi-physics conditions, like dynamic impact, fatigue loading, extreme temperatures, and moisture, among others, that make them vulnerable to degradation and damage, thereby severely reducing the composite's damage tolerance and durability. With emerging demands to improve vehicle performance and reduce cost, there is a critical need for novel avenues to mitigate or minimize their susceptibility to damage and failure. Introducing architecture within composites, which rely on combining solid distribution, base material properties, and morphologies, has shown great potential for achieving effective material properties unattainable by traditional composites. To that end, we conduct foundational research in advanced manufacturing to establish unique process-structure-property relationships for enabling architectures within polymer composites. Our underlying research theme is to elucidate how manufacturing-dictated internal micro-architecture influences the macroscale damage tolerance and durability of polymer composites.
In this talk, I will present our pioneering work on additive manufacturing of patterns/architectures for enhancing interlaminar properties in layered composites and bonded joints. I will demonstrate how differential bonding of patterns at the interlaminar regions can cause tortuous crack paths, which increases fracture toughness. This approach has great potential for reducing the susceptibility to delamination at free edges and under low-velocity impact loading in fiber-reinforced composites. Our process can be integrated within polymer composite manufacturing, like automated fiber placement, used for aircraft construction.