As the use of carbon fiber reinforced polymers (CFRP) increases in aerospace struc- tures it is important to use this material in an efficient manner such that both the weight and cost of the structure are minimized while maintaining its performance. To com- bat undesirable vibrational characteristics of a structure an optimization program was developed which takes advantage of the orthotropic nature of composite materials to maximize eigenfrequency bandgaps. The results from the optimization process were then fabricated and subjected to modal testing. The experiments show that local fiber angle optimization is a valid method for modifying the natural frequencies of a structure with the theoretical results generally predicting the performance of the optimized composite plates.

As the use of carbon fiber reinforced polymers (CFRP) increases in aerospace struc- tures it is important to use this material in an efficient manner such that both the weight and cost of the structure are minimized while maintaining its performance. To com- bat undesirable vibrational characteristics of a structure an optimization program was developed which takes advantage of the orthotropic nature of composite materials to maximize eigenfrequency bandgaps. The results from the optimization process were then fabricated and subjected to modal testing. The experiments show that local fiber angle optimization is a valid method for modifying the natural frequencies of a structure with the theoretical results generally predicting the performance of the optimized composite plates.

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<p> There is a current interest in exploring novel microstructural architectures that take advantage of the response of independent phases. Current guidelines in materials design are not just based on changing the properties of the different phases but also on modifying its base architecture. Hence, the mechanical behavior of composite materials can be adjusted by designing microstructures that alternate stiff and flexible constituents, combined with well-designed architectures. One source of inspiration to achieve these designs is Nature, where biologically mineralized composites can be taken as an example for the design of next-generation structural materials due to their low density, high-strength, and toughness currently unmatched by engineering technologies.</p><p><br></p> <p>The present work focuses on the modeling of biologically inspired composites, where the source of inspiration is the dactyl club of the Stomatopod. Particularly, we built computational models for different regions of the dactyl club, namely: periodic and impact regions. Thus, this research aimed to analyze the effect of microstructure present in the impact and periodic regions in the impact resistance associated with the materials present in the appendage of stomatopods. The main contributions of this work are twofold. First, we built a model that helped to study wave propagation in the periodic region. This helped to identify possible bandgaps and their influence on the wave propagation through the material. Later on, we extended what we learned from this material to study the bandgap tuning in bioinspired composites. Second, we helped to unveil new microstructural features in the impact region of the dactyl club. Specifically, the sinusoidally helicoidal composite and bicontinuous particulate layer. For these, structural features we developed finite element models to understand their mechanical behavior.</p><p><br></p> <p>The results in this work help to elucidate some new microstructures and present some guidelines in the design of architectured materials. By combining the current synthesis and advanced manufacturing methods with design elements from these biological structures we can realize potential blueprints for a new generation of advanced materials with a broad range of applications. Some of the possible applications include impact- and vibration-resistant coatings for buildings, body armors, aircraft, and automobiles, as well as in abrasion- and impact-resistant wind turbines.</p><br>