Bio-Inspired Strategies for Composite Crashworthiness: From Concept to Case Study

The rapid technological evolution in sectors such as aerospace, automotive, and energy is driving a growing demand for advanced materials that can deliver high mechanical performance while also being lightweight, safe, and reliable. These increasingly stringent requirements have pushed engineers to move beyond traditional metallic materials toward more advanced alternatives, most notably, fiber-reinforced polymer (FRP) composites. FRP offer exceptional stiffness-to-weight and strength-to-weight ratios, making them highly attractive for high-performance applications where weight savings and structural efficiency are critical. Despite these advantages, conventional FRP face significant limitations that restrict their broader application in critical or safety-sensitive scenarios. Their inherent brittleness and limited ability to absorb energy make them vulnerable to unpredictable failure under impact or dynamic loads, which poses challenges in areas such as crashworthiness, protective structures, and fatigue resistance. To overcome these drawbacks and further expand the potential of composite materials, engineers are increasingly embracing a new design paradigm — one that focuses not just on material selection, but on the development of materials with customized architectures and multifunctional properties. In this context, nature offers a profound source of inspiration. Over billions of years of evolution, biological materials have developed extremely sophisticated hierarchical structures that exhibit remarkable combinations of strength, toughness, resilience, and adaptability. Biomimicry, the practice of emulating these natural design strategies, provides a powerful framework for creating next-generation materials that meet the complex performance demands of modern industries. This dissertation applies biomimicry principles to enhance the damage tolerance and energy absorption of FRP composite structures. Specifically, the hierarchical microarchitecture of bone tissue is replicated using carbon and glass fibers to improve damage tolerance. At the same time, the intricate, lightweight morphology of diatom exoskeletons — characterized by their honeycomb-like geometry — is leveraged to increase energy absorption using additive manufacturing techniques and elastomeric materials. These bio-inspired strategies are integrated with finite element simulations, data-driven optimization, and experimental testing to develop novel design approaches for advanced composites with superior mechanical performance and multifunctional potential.